D
Morphine and its antagonist, naloxone, both act directly at the same receptors. Morphine causes activation, and naloxone prevents activation. Neither morphine nor naloxone acts to alter transmitter reuptake, release, or storage.
A nurse is teaching a group of nursing students about neuropharmacology. Which statement by a student about peripheral nervous system (PNS) drugs indicates a need for further teaching?
a.
“Drugs affecting axonal conduction have a variety of uses.”
b.
“Drugs that alter synaptic transmission can be highly selective.”
c.
“Many PNS drugs act by altering synaptic transmission.”
d.
“These drugs work by influencing receptor activity.”
A
Local anesthetics are the only drugs shown to work by altering axonal conduction. Any drug affecting axonal conduction would be nonselective, because axonal conduction of impulses is essentially the same in all neurons. In contrast, drugs that affect synaptic transmission can be highly selective, because each transmitter has different effects on receptor sites. Most PNS drugs work on synaptic transmission processes. Through their effects on transmitters, they influence receptor activity.
A nurse is teaching a group of nurses about neuropharmacology. The nurse asks which classes of drugs act by reducing axonal conduction. Which response by a participant is correct? a. Antihypertensives b. Antipsychotics c. Local anesthetics d. Antidepressants
C
Local anesthetics are the only drugs shown to work by reducing axonal conduction. Antihypertensives, antipsychotics, and antidepressants do not act by reducing axonal conduction.
A nurse is administering drug X to a patient. The drug information states that the drug acts by activating receptors in the peripheral nervous system by increasing transmitter synthesis. The nurse understands that the effect of this drug is to: a. activate axonal conduction. b. enhance transmitter storage. c. increase receptor activation. d. synthesize supertransmitters.
C
Drugs that increase transmitter synthesis increase receptor activation. Other drugs that alter transmitter synthesis can decrease synthesis and would cause decreased receptor activation. Drugs that affect transmitter production do not exert their effects on axonal conduction. The amount of transmitter produced does not directly affect transmitter storage. Some drugs that alter transmitter synthesis cause the synthesis of transmitter molecules that are more effective than the transmitter itself.
A nurse learns about a drug that interferes with transmitter storage in the PNS. The transmitter affected by this drug causes an increased heart rate. What response will the nurse expect to see when this drug is administered? a. Bradycardia b. Positive inotropic effects c. Prolonged receptor activation d. Tachycardia
A
Drugs that interfere with transmitter storage reduce receptor activation, because disruption of storage decreases the amount of transmitter available for release. Because this transmitter increases the heart rate, the result will be a decrease in the heart rate. Inotropic effects control the force of contraction, not the rate of contraction. Decreased transmitter storage would result in decreased receptor activation. Tachycardia would occur if transmitter availability were increased.
A patient receiving botulinum toxin injections to control muscle spasticity asks how the drug works. The nurse knows that this drug affects the transmitter acetylcholine by: a. inhibiting its release. b. interfering with its storage. c. preventing its reuptake. d. promoting its synthesis.
A
Acetylcholine is a neurotransmitter that activates receptors that increase skeletal muscle contraction. Botulinum toxin inhibits the release of this transmitter. It does not interfere with storage, reuptake, or synthesis of acetylcholine.
A patient has allergies and takes an antihistamine. The patient wants to know how the drug works. The nurse understands that antihistamines work because they are what? a. Activators b. Agonists c. Antagonists d. Antidotes
C
Antihistamines bind to receptors to prevent activation by histamine; this makes antihistamines antagonist drugs. Antihistamines do not activate receptors. Agonist drugs activate receptors; they are not antidotes.
A nursing student asks about drugs that interfere with the termination of transmitter action. Which statement by the nurse is correct?
a.
“Drugs act on this process by altering the diffusion of the transmitter away from the synaptic gap.”
b.
“Drugs can interfere with termination by either increasing or decreasing reuptake of the transmitter.”
c.
“Drugs in this category lead to decreased activation by the transmitter in the synapse.”
d.
“These drugs reduce either reuptake or degradation of the transmitter, causing an increase in receptor activation.”
D
Drugs that interfere with termination of transmitter action do so by blocking transmitter reuptake or inhibiting transmitter degradation, resulting in increased receptor activation, because more of the transmitter remains available. Diffusion of the transmitter occurs naturally, but it is a slow process with little clinical significance. Drugs that alter this process cause a decrease in reuptake, not an increase. The effect of drugs that interfere with termination of transmitter action is increased activation.
The nurse understands that patients are given beta1 agonists to treat \_\_\_\_\_ failure. a. heart b. kidney c. respiratory d. liver
A
A beta1 agonist increases the patient’s heart rate and blood pressure and is used in heart failure. Beta1 agonists would not be used for kidney, respiratory, or liver failure.
A nurse is teaching a patient about a medication that alters sympathetic nervous system functions. To evaluate understanding, the nurse asks the patient to describe which functions the sympathetic nervous system regulates. Which answer indicates the need for further teaching? a. “The digestive functions of the body” b. “The cardiovascular system” c. “The fight-or-flight response” d. “Body temperature”
A
The sympathetic nervous system does not regulate digestive functions of the body—the parasympathetic nervous system does; further education is needed. The sympathetic nervous system regulates the cardiovascular system, the fight-or-flight response, and the body temperature; no further education is needed.
A patient is wheezing and short of breath. The nurse assesses a heart rate of 88 beats per minute, a respiratory rate of 24 breaths per minute, and a blood pressure of 124/78 mm Hg. The prescriber orders a nonspecific beta agonist medication. Besides evaluating the patient for a reduction in respiratory distress, the nurse will monitor for which side effect? a. Hypotension b. Tachycardia c. Tachypnea d. Urinary retention
B
Beta agonists are used for asthma because of their beta2 effects on bronchial smooth muscle, causing dilation. Beta1 effects cause tachycardia and hypertension. Beta receptors do not exert effects on the bladder.
A nurse is teaching a group of nursing students about neurotransmitters. Which statement by a student about acetylcholine indicates a need for further teaching?
a.
“It activates three cholinergic receptor subtypes.”
b.
“It has effects in the parasympathetic, sympathetic, and somatic nervous systems.”
c.
“It is used at most junctions of the peripheral nervous system.”
d.
“Its transmission is terminated by reuptake into the cholinergic nerve terminal.”
D Acetylcholine (ACh) is destroyed by acetylcholinesterase, an enzyme that degrades ACh into two inactive products: acetate and choline. Choline is taken up into the nerve terminal. ACh activates three receptor sites: nicotinicN, nicotinicM, and muscarinic. ACh has effects throughout the peripheral nervous system (PNS) and is used at most junctions in the PNS.How well did you know this? Not at all
A nurse is administering an agonist drug that acts on postganglionic neurons of the sympathetic nervous system. Which response will the nurse expect to see? a. Decreased sweating b. Bronchodilation c. Increased cardiac output d. Pinpoint pupils
C Norepinephrine (NE) is the most common neurotransmitter released by all postganglionic neurons of the sympathetic nervous system except those going to sweat glands where ACh is the neurotransmitter. NE acts on alpha1, alpha2, and beta1 receptors to increase the force and rate of cardiac contraction, thus increasing cardiac output. ACh would increase sweating. Bronchodilation occurs when epinephrine activates beta2 receptors on bronchial smooth muscle. NE affects alpha1 receptors to dilate the pupils.How well did you know this? Not at all
Many medications list side effects that include dry mouth, constipation, and urinary retention. What kind of effects are these? a. Alpha adrenergic b. Anticholinergic c. Beta adrenergic d. Sympathetic
B
Cholinergic stimulation by ACh causes increased salivation, increased gastrointestinal (GI) motility, and relaxation of the bladder trigone and sphincter. Anticholinergic medications inhibit these responses, causing dry mouth, constipation, and urinary retention. Alpha-adrenergic agents effect processes in the sympathetic nervous system, causing peripheral vasoconstriction and pupil dilation, among other effects. The effects of beta-adrenergic medications are seen mostly in the heart and blood vessels. The sympathetic nervous system has both cholinergic and adrenergic transmitters.
A nurse is explaining activation of beta2 receptors to some student nurses during a clinical rotation at the hospital. Which statement by a student demonstrates a need for further teaching?
a.
“Beta2 activation results in bronchodilation.”
b.
“Beta2 activation results in contraction of uterine muscle.”
c.
“Beta2 activation results in glycogenolysis.”
d.
“Beta2 activation results in vasodilation of skeletal muscles.”
B
Beta2 activation would result in relaxation of uterine smooth muscle, not contraction; this statement indicates a need for further teaching. Bronchodilation is an effect of beta2 activation; no further teaching is needed. Beta2 activation does result in glycogenolysis; no further teaching is needed. Beta2 activation does result in vasodilation of skeletal muscle; no further teaching is needed.
A pregnant patient is in premature labor. Which class of drug will she be given? a. Alpha1 agonist b. Anticholinergic c. Beta2 agonist d. Beta2 antagonist
C
Beta2 agonists cause relaxation of uterine muscle, slowing or stopping the contractions that precipitate labor. An alpha1 agonist would have effects on the heart and arterioles. Anticholinergic drugs generally are given for their effects on the urinary and GI tracts and do not affect uterine muscle. A beta2 antagonist would cause increased constriction of uterine muscle.
A patient is to receive a beta agonist. Before administration of this medication, which assessment finding would most concern the nurse? a. Pulse oximetry reading of 88% b. Blood pressure of 100/60 mm Hg c. Respiratory rate of 28 breaths per minute d. Heart rate of 110 beats per minute
D
A beta agonist dilates respiratory smooth muscle, but as a side effect, it can stimulate the heart. A heart rate of 110 beats per minute is a concern, because this medication may further increase the already elevated heart rate. A pulse oximetry reading of 88% is a concern, but the medication causes bronchodilation and increased oxygenation; this should increase the pulse oximetry reading. A blood pressure of 100/60 mm Hg is on the low side, but this medication may actually cause an increase in blood pressure as a side effect; this should not concern the nurse before administration of the medication. A respiratory rate of 28 breaths per minute is elevated; however, this medication should increase oxygenation by bronchodilation, and the patient’s respiratory rate should decrease once oxygenation has improved. Therefore, this should not concern the nurse.
A prescriber has ordered pilocarpine (Pilocar). A nurse understands that the drug stimulates muscarinic receptors and would expect the drug to have which action?
a.
Reduce excessive secretions in a postoperative patient
b.
Lower intraocular pressure in patients with glaucoma
c.
Inhibit muscular activity in the bladder
d.
Prevent hypertensive crisis
B
Pilocarpine is a muscarinic agonist used mainly for topical therapy of glaucoma to reduce intraocular pressure. Pilocarpine is not indicated for the treatment of excessive secretions and mucus; in fact, pilocarpine is used to treat dry mouth. Pilocarpine does not inhibit muscular activity in the bladder. Pilocarpine is not used to prevent hypertensive crisis.
A patient has developed muscarinic antagonist toxicity from ingestion of an unknown chemical. The nurse should prepare to administer which medication? a. Atropine (Sal-Tropine) IV b. Physostigmine (Antilirium) c. An acetylcholinesterase activator d. Pseudoephedrine (Ephedrine)
B
Physostigmine is indicated for muscarinic antagonist toxicity. Atropine is a drying agent and would only complicate the drying action that arises from the muscarinic antagonist. An acetylcholinesterase activator would only contribute to dryness that arises from the muscarinic antagonist. Ephedrine is not indicated for muscarinic antagonist toxicity.
A prescriber has ordered bethanechol (Urecholine) for a postoperative patient who has urinary retention. The nurse reviews the patient’s chart before giving the drug. Which part of the patient’s history would be a contraindication to using this drug? a. Asthma as a child b. Gastroesophageal reflux c. Hypertension d. Hypothyroidism
A
Bethanechol is contraindicated in patients with active or latent asthma, because activation of muscarinic receptors in the lungs causes bronchoconstriction. It increases the tone and motility of the gastrointestinal (GI) tract and is not contraindicated in patients with reflux. It causes vasodilation and would actually lower blood pressure in a hypertensive patient. It causes dysrhythmias in hyperthyroid patients.
A patient will begin using a transdermal preparation of a muscarinic antagonist for overactive bladder (OAB). The nurse teaches the patient what to do if side effects occur. Which statement by the patient indicates the need for further teaching?
a.
“I can use sugar-free gum for dry mouth.”
b.
“I may need laxatives for constipation.”
c.
“I should keep the site covered to prevent other people from getting the medicine.”
d.
“I will take Benadryl for any itching caused by a local reaction to the patch.”
D
Benadryl is an antihistamine, and even though it is not classified as a muscarinic antagonist, it has anticholinergic effects. Giving it with a muscarinic antagonist greatly enhances these effects, so it should not be used. Muscarinic antagonists cause dry mouth, and patients should be taught to use sugar-free gum or candies to help with this. Muscarinic antagonists can cause constipation, and laxatives may be used. Medication applied topically can be transferred to others who come in contact with the skin, so the site should be covered.
An older adult patient who lives alone and is somewhat forgetful has an overactive bladder and reports occasional constipation. Which treatment will the nurse anticipate for this patient?
a.
Behavioral therapy
b.
Oxybutynin (Ditropan XL) extended-release tablets
c.
Oxybutynin (Oxytrol) transdermal patch
d.
Percutaneous tibial nerve stimulation (PTNS)
C
The transdermal patch is applied weekly and may be the best option for a patient who is more likely to forget to take a daily medication. The transdermal preparation has fewer side effects than the systemic dose so is less likely to increase this patient’s constipation. Behavioral therapy should be tried first in patients who can participate. However, it is not the best option for a forgetful patient who lives alone, because it requires scheduled voiding and timing of fluid intake. The extended-release tablets must be given daily, and this patient may not remember to take them. PTNS is used after behavioral and drug therapies have failed.
A patient received atropine intravenously before surgery. The recovery room nurse notes that the patient is delirious upon awakening, has a heart rate of 96 beats per minute, a respiratory rate of 22 breaths per minute, and a blood pressure of 110/78 mm Hg. The nurse notifies the anesthesiologist, who will order:
a.
activated charcoal to minimize intestinal absorption of the antimuscarinic agent.
b.
an acetylcholinesterase inhibitor to compete with the antimuscarinic agent at receptors.
c.
an antipsychotic medication to treat the patient’s central nervous system symptoms.
d.
ipratropium bromide (Atrovent) to counter the respiratory effects of the antimuscarinic agent.
B
This patient is showing signs of antimuscarinic toxicity, caused by the atropine given during surgery. The most effective antidote is physostigmine, which inhibits acetylcholinesterase, allowing acetylcholine to build up at cholinergic junctions and compete with the antimuscarinic agent for receptor binding. Activated charcoal is only useful if an antimuscarinic agent has been ingested, because it impedes absorption from the GI tract. Because this patient’s psychotic symptoms are caused by an antimuscarinic agent, physostigmine should be given to treat the cause; an antipsychotic medication would only treat the symptom. Ipratropium bromide is an antimuscarinic agent and would only compound the effects. This patient’s respiratory rate is only mildly elevated.
Bethanechol (Urecholine) is used to treat urinary retention but is being investigated for use in which other condition? a. Gastric ulcers b. Gastroesophageal reflux c. Hypotension d. Intestinal obstruction
B
Bethanechol is being investigated for treatment for gastroesophageal reflux disease (GERD) because of its effects on esophageal motility and the lower esophageal sphincter. Bethanechol stimulates acid secretion and could intensify ulcer formation. Bethanechol can cause hypotension. Because bethanechol increases the motility and tone of intestinal smooth muscle, the presence of an obstruction could lead to bowel rupture.
A patient receives topical atropine to facilitate an eye examination. The nurse will tell the patient to remain in a darkened room or to wear sunglasses for several hours until the effects of the medication wear off. This teaching is based on the nurse’s knowledge that muscarinic antagonists cause: a. elevation of intraocular pressure. b. miosis and ciliary muscle contraction c. paralysis of the iris sphincter. d. relaxation of ciliary muscles.
C
By blocking muscarinic receptors in the eye, atropine causes paralysis of the iris sphincter, which prevents constriction of the pupil; consequently, the eye cannot adapt to bright light. This also causes an elevation in intraocular pressure, which increases the risk of glaucoma. However, it is not an indication for wearing darkened glasses. Muscarinic agonists cause miosis; atropine causes mydriasis. The effect of relaxing ciliary muscles focuses the eye for far vision, causing blurred vision.
A nurse is caring for a patient who has myasthenia gravis. The prescriber has ordered neostigmine (Prostigmin). An important initial nursing action before administration of the medication includes assessing: a. the ability to raise the eyelids. b. level of fatigue. c. skeletal muscle strength. d. swallowing ability.
D
Many patients hospitalized for myasthenia gravis do not have the muscle strength to swallow well and need a parenteral form of the medication; therefore, assessing the patient’s ability to swallow is an important initial safety measure. Evaluating the patient’s ability to raise the eyelids, level of fatigue, and skeletal muscle strength are all important assessments both before drug administration and during drug treatment, because they indicate the effectiveness of the drug and help determine subsequent doses.
A nurse working in the emergency department is assigned to a child who is arriving by ambulance after being involved in a spill of organophosphate insecticides. What will the nurse expect to be the initial priority for treating this child?
a.
Administering diphenhydramine to control secretions
b.
Giving diazepam to control seizures
c.
Providing mechanical ventilation and oxygen
d.
Reporting the spill to the Environmental Protection Agency
C
All of these courses of action may be part of the treatment. However, the initial concern is to prevent death from apnea caused by laryngospasm, bronchoconstriction, and paralysis leading to apnea; therefore, maintaining an airway is the most important consideration. Pralidoxime is the specific antidote and should be given next. Atropine is used to control secretions. Diazepam is given when seizures occur. Reporting the accident to the proper authorities is not a priority during a life-threatening emergency.
A patient who has myasthenia gravis will be taking neostigmine (Prostigmin). What will the nurse emphasize when teaching this patient about the medication?
a.
“Stop taking the drug if you have diarrhea.”
b.
“Take a supplementary dose before exercise.”
c.
“Use atropine if you have excessive salivation.”
d.
“Withhold the dose if ptosis occurs.”
B
Neostigmine doses must be adjusted continually, and patients usually need supplemental doses before exertion; therefore, patients must be taught how to modify doses as needed. Increased gastrointestinal (GI) secretions can cause loose stools; this is a known adverse effect that does not warrant stopping the drug. Atropine will help with excessive salivation but should not be used routinely, because it can mask the early signs of anticholinesterase overdose. Ptosis is one of the symptoms of myasthenia gravis and is an indication for taking neostigmine.
Two nurses are discussing the major differences between physostigmine (Antilirium) and neostigmine (Prostigmin). One nurse correctly makes which statement about physostigmine (Antilirium)?
a.
“It is not effective for treating poisoning by muscarinic blocking drugs.”
b.
“It can readily cross the blood-brain barrier.”
c.
“It does not cause any side effects.”
d.
“It can be given by all routes.”
B
The basic pharmacology of physostigmine is nearly identical to that of neostigmine, except that physostigmine readily crosses membranes, including the blood-brain barrier; neostigmine does not. Physostigmine and neostigmine are both effective for treating poisoning by muscarinic blocking drugs. Neither physostigmine nor neostigmine is devoid of side effects. Physostigmine can be given only intramuscularly (IM) or intravenously (IV); neostigmine is given orally (PO), IM, IV, and subcutaneously (subQ).
A nurse is helping a nursing student who is administering a medication to a patient with myasthenia gravis. Which statement by the student indicates the need for further teaching?
a.
“I will ask the patient to sip some water before giving the medication.”
b.
“I will let the patient sleep after giving the medication, because rest is important.”
c.
“I will record muscle strength assessments before and after I give the medication.”
d.
“I will report excessive salivation to the patient’s prescriber.”
B
An important assessment indicating the medication’s effectiveness is evaluating a patient’s ability to raise the eyelids. Letting the patient sleep, even though rest is important, would prevent the nurse from making this assessment. To make sure the patient can safely swallow a pill, the nurse must evaluate swallowing ability by asking the patient to take a sip of water. Muscle strength assessments before and after medication administration help the nurse evaluate the medication’s effectiveness. Excessive salivation may be a sign of drug toxicity and should be reported.
A patient with myasthenia gravis who is taking a cholinesterase inhibitor is being admitted to the intensive care unit and is on mechanical ventilation. The prescriber has ordered a challenge dose of edrophonium to distinguish between a myasthenic crisis and a medication overdose. The nurse will expect to do what?
a.
Administer neostigmine if muscle strength decreases.
b.
Be prepared to administer atropine if muscle weakness increases.
c.
Give a second dose of edrophonium if no improvement is seen.
d.
Give pralidoxime (Protopam) if cholinergic symptoms worsen.
B
Edrophonium is an ultra-short-acting cholinesterase inhibitor used to distinguish between a myasthenic crisis and a cholinesterase inhibitor overdose, because weakness or paralysis can occur with both. If the symptoms are intensified and muscle weakness increases, the crisis is cholinergic, meaning that the patient is having toxic effects from the cholinesterase inhibitor and needs atropine as an antidote. Neostigmine would be given if the patient shows improved muscle strength, because that would indicate that the patient’s symptoms are the result of a myasthenic crisis. A second dose of edrophonium would only worsen the symptoms. Pralidoxime is used to treat poisoning caused by irreversible cholinesterase inhibitors
A nurse is teaching a new emergency department nurse about emergency medications. When asked to describe the uses of pralidoxime (Protopam), the new nurse makes which correct statement?
a.
“It exerts its greatest effects at muscarinic and ganglionic sites.”
b.
“It is used to treat poisoning by reversible cholinesterase inhibitors.”
c.
“It may not be effective if not given immediately.”
d.
“It reverses the effects of organophosphate insecticides in the central nervous system.”
C
Pralidoxime must be given soon after organophosphate poisoning has occurred because of a process called aging, in which the bond between the organophosphate inhibitor and cholinesterase increases in strength, making pralidoxime ineffective. For some of these poisons, aging can occur within minutes. Pralidoxime has its greatest effects at the neuromuscular junction, not the muscarinic and ganglionic sites. It is used to treat poisoning by irreversible cholinesterase inhibitors. It does not cross the blood-brain barrier and thus does not have effects in the CNS.
A patient is experiencing toxic side effects from atropine, including delirium and hallucinations. Which medication will the nurse expect to administer? a. Donepezil (Aricept) b. Edrophonium (Reversol) c. Neostigmine (Prostigmin) d. Physostigmine
D
Physostigmine is the drug of choice for treating poisoning from atropine and other drugs that cause muscarinic blockade. Donepezil is used to treat Alzheimer’s disease. Edrophonium is used to distinguish between a myasthenic crisis and a cholinesterase inhibitor overdose. Neostigmine does not cross the blood-brain barrier and would not effectively treat this patient’s CNS symptoms.
A nurse is teaching a group of nursing students about irreversible cholinesterase inhibitors. Which statement by a student indicates understanding of the teaching?
a.
“Diazepam is given to reverse inhibition of cholinesterase when overdose occurs.”
b.
“Irreversible cholinesterase inhibitors are rapidly absorbed by all routes.”
c.
“These agents are often used to treat glaucoma.”
d.
“Toxic doses of these agents produce an anticholinergic crisis.”
B
Almost all of these agents are highly lipid soluble, making them readily absorbed from all routes of administration. Diazepam is used during overdose but only to control seizures and not to reverse effects. The only clinical use for these agents is to treat glaucoma, but this use is limited. Toxic doses of these agents produce a cholinergic, not an anticholinergic, crisis.
A nurse is caring for an intubated patient who is receiving pancuronium for neuromuscular blockade. The patient’s eyes are closed, and the patient is not moving any extremities. The heart rate is 76 beats per minute, and the blood pressure is 110/70 mm Hg. The nurse caring for this patient will do what?
a.
Request an order for an antihistamine to prevent a further drop in blood pressure.
b.
Request an order for serum electrolytes to evaluate for hyperkalemia.
c.
Review the patient’s chart for a history of myasthenia gravis (MG).
d.
Talk to the patient while giving care and explain all procedures.
D
Pancuronium is a competitive neuromuscular blocker and is used to paralyze skeletal muscles by neuromuscular blockade. The first muscles affected are those of the eyelids, so patients given this medication cannot open their eyes. Inability to move the extremities is an expected effect. Because these medications do not have central nervous system (CNS) effects, the patient is conscious and awake; therefore, caregivers should continue to talk to the patient while providing care. Atracurium, not pancuronium, can cause hypotension secondary to histamine release. High potassium levels would reduce paralysis. Patients with a history of MG would have increased paralysis. Nothing indicates that this patient is experiencing extreme effects from this medication.
While preparing a patient for a procedure in which a neuromuscular blocking agent will be used, the nurse reviews the patient’s preprocedure laboratory values. Which abnormality would cause the most concern? a. Hyponatremia b. Hypercalcemia c. Hypomagnesemia d. Hypokalemia
D
Low potassium levels can enhance paralysis, whereas high potassium levels can reduce paralysis. Because electrolyte status can influence the depth of neuromuscular blockade, it is important to maintain normal electrolyte balance. There are no indications that sodium, calcium, and/or magnesium have effects similar to those of potassium in relation to neuromuscular blocking agents.
Which of the following areas of the body shows the effects of tubocurarine last? a. Levator muscle of the eyelids and the muscles of mastication b. Muscles in the lower extremities c. Muscles controlling the glottis d. Muscles of respiration and the diaphragm
D
Although tubocurarine can paralyze all skeletal muscles, not all muscles are affected at once. The last muscles affected by tubocurarine are the muscles of respiration, including the intercostals, and the diaphragm. The first to become paralyzed are the levator muscle of the eyelids and the muscles of mastication. Paralysis occurs next in the muscles of the limbs, abdomen, and glottis.
A patient will receive atracurium (Tracrium) during surgery for neuromuscular blockade. The nurse caring for this patient will correctly perform which of the following actions?
a.
Assess the patient for signs of CNS depression.
b.
Ensure that dantrolene is available in case of a serious adverse reaction.
c.
Monitor the patient’s blood pressure closely.
d.
Review the preprocedure laboratory values related to renal and hepatic function.
C Atracurium is used for muscle relaxation during surgery. Unlike other drugs in this class, it can cause hypotension secondary to antihistamine release. Cholinesterase inhibitors can reverse this reaction. Drugs in this class do not cause CNS depression. Dantrolene is the agent used to treat malignant hyperthermia, which is triggered by succinylcholine. Atracurium is eliminated primarily by plasma cholinesterase and not by the renal or hepatic routes
While preparing a patient for a second esophageal dilation procedure, the nurse explains that succinylcholine (Anectine) will be used for muscle relaxation. The patient is anxious and reports not being able to swallow for several hours after the previous procedure. What will the nurse do?
a.
Be prepared to provide mechanical ventilation after the procedure.
b.
Have dantrolene available, because this patient is at increased risk for side effects.
c.
Reassure the patient that this is expected after neuromuscular blockade.
d.
Request an order for a pseudocholinesterase level.
D
Succinylcholine is used for muscle relaxation during short procedures, such as esophageal dilation, because of its short duration. The effects wear off minutes after the drug is withdrawn, because plasma pseudocholinesterase quickly degrades it. Patients who have prolonged effects may have low plasma pseudocholinesterase levels and should be evaluated if this is suspected. Mechanical ventilation may be necessary if the drug is given, but the prudent nurse would rather avoid this by taking preventive measures instead of treating the adverse reaction after the fact. Dantrolene should always be available when succinylcholine is used because of the risk of malignant hyperthermia; however, nothing indicates that this particular patient is at greater risk than others. Prolonged neuromuscular blockade is not a normal reaction.
A nurse is reviewing nursing actions for emergency treatment of malignant hyperthermia with a group of nursing students. Which statement by a student indicates a need for further teaching?
a.
“Analgesics should be given to help with muscle pain.”
b.
“Dantrolene helps to slow the metabolic activity in skeletal muscles.”
c.
“If malignant hyperthermia occurs, the succinylcholine must be stopped immediately.”
d.
“The patient may need an intravenous infusion of cold saline.”
A
Malignant hyperthermia is a rare but potentially fatal adverse reaction that can be triggered by succinylcholine. Muscle pain is an expected adverse effect of succinylcholine that is thought to be caused by the muscle contractions that occur during induction; analgesics can be given, but this effect usually occurs 10 to 12 hours after the procedure and is not an emergency. Dantrolene is given because it slows metabolic activity in skeletal muscles, resulting in decreased heat production. Succinylcholine should be stopped immediately if malignant hyperthermia occurs. Cold saline, given intravenously, often is necessary to lower a patient’s temperature.
A patient receives a neuromuscular blocking agent before a procedure. The patient’s eyes close. The nurse knows this is a sign that the patient: a. has fallen asleep. b. has received a toxic dose of the medication. c. is beginning to feel the drug’s effects. d. may need mechanical ventilation.
C
Neuromuscular blocking agents relax skeletal muscle to produce flaccid paralysis; the first muscles to be affected are the levator muscle of the eyelids and the muscles of mastication. These agents do not affect the CNS. Because the drug has just taken effect, a toxic dose is not yet a concern. Mechanical ventilation is necessary when the drug affects the intercostal muscles and the diaphragm, interfering with respiration.
Small doses of tubocurarine are administered when patients are suspected of having a myasthenia gravis crisis. If the patient develops increased muscle weakness in response to the tubocurarine, the nurse should prepare to administer what kind of drug? a. Cholinesterase inhibitor b. Dopamine agonist c. Ganglionic blocker d. Neuromuscular blocking agent
A
If the patient displays increased muscle weakness, this is an adverse effect of the tubocurarine, and respiratory depression may ensue. A dopamine antagonist would not be indicated to reverse the effects of the tubocurarine. Ganglionic blockers interrupt impulse transmission through ganglia of the autonomic nervous system; they are nonselective and no longer have therapeutic uses. A neuromuscular blocking agent would increase muscle paralysis and make the condition worse.
A patient with hepatitis requires endotracheal intubation. Which agent does the nurse expect to be administered to facilitate this procedure? a. Atropine b. Cisatracurium (Nimbex) c. Rocuronium (Zemuron) d. Vecuronium (Norcuron)
B
Cisatracurium is used for muscle relaxation during intubation. It is eliminated by spontaneous degradation, not by hepatic metabolism or renal excretion. Atropine is not used for muscle relaxation; it is an anticholinergic drug used to control secretions during procedures. Rocuronium is eliminated by hepatic metabolism. Vecuronium is excreted in bile and can cause prolonged paralysis in patients with liver dysfunction.
A nurse is teaching a group of nursing students about neuromuscular blocking agents. For what may these agents be used? (Select all that apply.) a. Analgesia b. Electroshock therapy c. Malignant hyperthermia d. Mechanical ventilation e. Surgery
B, D, E
Neuromuscular blocking agents are used to produce muscle paralysis in procedures including electroconvulsive therapy (ECT), intubation and ventilation, and surgery. They do not produce analgesia. They are not used to treat malignant hyperthermia.
A nurse is teaching a nursing student about the two classes of adrenergic agonist drugs. Which statement by the nursing student indicates understanding of the teaching?
a.
“Catecholamines may be given orally.”
b.
“Catecholamines often require continuous infusion to be effective.”
c.
“Noncatecholamines do not cross the blood-brain barrier.”
d.
“Noncatecholamines undergo rapid degradation by monoamine oxidase.”
B
Catecholamines undergo rapid degradation by monoamine oxidase (MAO) and catechol-O-methyltransferase (COMT). Consequently, they have a brief duration of action, and continuous infusion often is required to maintain the drug’s effects. Catecholamines cannot be used orally. Catecholamines do not cross the blood-brain barrier; noncatecholamines do. Noncatecholamines are not degraded by MAO.
Dopamine is administered to a patient who has been experiencing hypotensive episodes. Other than an increase in blood pressure, which indicator would the nurse use to evaluate a successful response? a. Decrease in pulse b. Increase in urine output c. Weight gain d. Improved gastric motility
B
Dopamine would cause an increase in urine output, because cardiac output is increased as a result of the increase in blood pressure. The effectiveness of dopamine would not be measured by a decrease in pulse, because dopamine’s primary effect is to increase blood pressure. Dopamine’s effectiveness would not be evaluated by a weight gain. Dopamine’s effectiveness would not be evaluated by improved gastric motility.
A nursing student asks the nurse about receptor specificity of adrenergic agonist medications. What will the nurse say?
a.
“As the dosage of these medications increases, drugs in this class are more selective.”
b.
“Dopamine is selective for dopamine receptors and has no effects on alpha or beta receptors.”
c.
“Epinephrine is the most selective alpha-adrenergic agonist medication.”
d.
“Specificity is relative and is dose dependent.”
D Receptor specificity is relative, not absolute, and is dose dependent. At low doses, selectivity is maximal, and selectivity declines as the dose increases. Dopamine is the only drug in this class that acts on dopamine receptors, but it also has effects on alpha and beta receptors. Epinephrine is the least selective of this class
A patient brought to the emergency department requires sutures. The prescriber orders a local anesthetic with epinephrine. The nurse understands that epinephrine is ordered to: a. prevent hypertension induced by the anesthetic. b. prolong absorption of the anesthetic. c. reduce anesthetic-induced nausea. d. reduce the pain of an injection.
B
Epinephrine prolongs absorption of the anesthetic, because it is an alpha1 agonist. It is frequently combined with a local anesthetic for this purpose. Local anesthetics do not induce hypertension; therefore, epinephrine would not be needed to prevent it. Epinephrine does not act as an antiemetic and would not reduce anesthetic-induced nausea. Epinephrine is not used to reduce the pain of an injection.
A nurse is administering intravenous dopamine (Intropin) to a patient in the intensive care unit. Which assessment finding would cause the most concern? a. Blood pressure of 100/70 mm Hg b. Increased urine output c. Edema at the IV insertion site d. Headache
C
The nurse would be concerned if the patient’s peripheral IV were edematous, because this could signal infiltration of the solution into the tissues. Dopamine can cause necrosis if it extravasates. Dopamine is indicated to increase the patient’s blood pressure; this blood pressure reading is acceptable. When dopamine is effective at increasing cardiac output, it also causes an increase in urine output. Headache is not a contraindication to the use of dopamine.
A patient with asthma uses albuterol (Ventolin) for wheezing. The nurse assesses the patient and notes vital signs of HR, 96 beats per minute; RR, 18 breaths per minute; and BP, 116/78 mm Hg. The patient has clear breath sounds and hand tremors. What will the nurse do?
a.
Ask the patient how often the inhaler is used.
b.
Check the patient’s blood glucose level.
c.
Request an order for isoproterenol (Isuprel) to reduce side effects.
d.
Stop the medication and report the tremors to the provider.
A
Tachycardia is a response to activation of beta1 receptors. It can occur when large doses of albuterol are used and selectivity decreases. The nurse should question the patient about the number of inhalations used. Isoproterenol can cause hyperglycemia in diabetic patients. Isoproterenol has more side effects than albuterol. Tremors are an expected side effect and are not an indication for stopping the drug.
A nurse is teaching parents how to use an Epi-Pen for their child, who has a peanut allergy. Which statement by the parents indicates understanding of the teaching?
a.
“After using the Epi-Pen, we must go to the emergency department.”
b.
“The Epi-Pen should be stored in the refrigerator, because epinephrine is sensitive to heat.”
c.
“The teacher should call us when symptoms start so that we can bring the Epi-Pen to school.”
d.
“We should jab the device into the thigh until it is empty of solution.”
A
After using the Epi-Pen, it is important that the individual get medical attention as quickly as possible. The effects of epinephrine fade in 10 to 20 minutes, and the anaphylactic reaction can be biphasic and prolonged. Epinephrine is sensitive to heat, but storing the device in the refrigerator can compromise the injection mechanism; the device should be stored at room temperature in a dark place. Individuals who need an Epi-Pen must have the device with them at all times; any delay in treatment can be fatal, because anaphylaxis can occur within minutes after exposure. The Epi-Pen contains 2 mL of epinephrine, but only 0.3 mL is injected; the device will not be empty with a successful injection.
Because they cause vasoconstriction, alpha1-adrenergic agonists are especially useful for:
a.
extending the duration of local anesthetics.
b.
producing mydriasis to facilitate ophthalmic examinations.
c.
slowing the heart rate in tachycardic patients.
d.
treating hypotension.
A
The vasoconstrictive effects of alpha1-adrenergic agonists, such as epinephrine, help delay absorption of a local anesthetic, prolonging the anesthetic’s effects. These agents can increase blood pressure but are not the primary drugs used except in emergency situations. Alpha1 receptors in the radial muscles of the iris, not vasoconstriction, cause mydriasis. Reflex bradycardia is a side effect and not a clinical use of these agents.
A patient is admitted to the intensive care unit for treatment of shock. The prescriber orders isoproterenol (Isuprel). The nurse expects this drug to increase tissue perfusion in this patient by activating:
a.
alpha1 receptors to cause vasoconstriction.
b.
alpha1 receptors to increase blood pressure.
c.
beta1 receptors to cause a positive inotropic effect.
d.
beta2 receptors to cause bronchodilation.
C
Isoproterenol is used for shock because of its actions on beta1 receptors in the heart. It has a positive inotropic effect, which improves cardiac output and thus increases tissue perfusion. Isoproterenol does not affect alpha1 receptors. Although it activates beta2 receptors to cause bronchodilation, this is not indicated for the treatment of shock.
A pregnant patient with diabetes and hypertension is given isoproterenol (Isuprel) to delay preterm labor. Which side effect might the nurse expect? a. Bronchospasm b. Decreased urine output c. Hyperglycemia d. Hypotension
C
In diabetic patients, isoproterenol can cause hyperglycemia by promoting beta2-mediated glycogenolysis. It is also used to treat asthma and causes bronchodilation, not bronchospasm. It acts on beta1 receptors in the heart to increase cardiac output, which may increase urine output. It increases blood pressure.
A nursing student asks why albuterol, which is selective for beta2 receptors, causes an increased heart rate in some patients. How does the nurse respond?
a.
“Adrenergic agonists can lose their selectivity when given at higher doses.”
b.
“Bronchodilation lowers blood pressure, which causes a reflex tachycardia.”
c.
“Some patients metabolize the drug differently and have unusual side effects.”
d.
“Systemic effects are intensified with inhaled doses.”
A
Although albuterol affects the beta2 receptors, at higher doses it may also activate beta1 receptors, causing an increase in the heart rate. Bronchodilation does not lower the blood pressure, and activation of beta1 receptors actually may increase it. Tachycardia is a common side effect. The inhaled route reduces the likelihood of systemic side effects.
A patient is receiving dobutamine (Dobutrex) as a continuous infusion in the immediate postoperative period. The patient also is receiving a diuretic. What adverse drug reactions are possible in this patient? (Select all that apply.) a. Angina b. Dysrhythmias c. Hypotension d. Oliguria e. Tachycardia
A, B, E
Angina, dysrhythmias, and tachycardia are the most common adverse effects of dopamine; general anesthetics can increase the likelihood of dysrhythmias. Dopamine elevates blood pressure by increasing cardiac output. Diuretics complement the beneficial effects of dopamine on the kidney, so urine output would be increased, not decreased.
A nurse is teaching nursing students about the use of alpha-adrenergic antagonists. Which statement by the student indicates the need for further teaching?
a.
“Alpha-adrenergic antagonists block alpha1 receptors on arterioles and veins.”
b.
“Dilation of arterioles has a direct effect on arterial pressure.”
c.
“Dilation of veins by alpha-adrenergic antagonists improves cardiac output.”
d.
“Venous dilation by alpha-adrenergic antagonists indirectly lowers arterial pressure.”
C
Cardiac output is decreased as a result of the venous dilation caused by alpha-adrenergic antagonists. Alpha-adrenergic antagonists block alpha1 receptors on both arterioles and veins. When alpha1 receptors on arterioles are blocked by alpha-adrenergic antagonists, a direct effect on arterial pressure occurs. When alpha1 receptors on veins are blocked by alpha-adrenergic antagonists, an indirect effect on arterial pressure occurs
A patient with pheochromocytoma is admitted for surgery. The surgeon has ordered an alpha-blocking agent to be given preoperatively. What does the nurse understand about this agent?
a.
It is ordered to prevent perioperative hypertensive crisis.
b.
It prevents secretion of catecholamines by the adrenal tumor.
c.
It reduces contraction of smooth muscles in the adrenal medulla.
d.
It is given chronically after the surgery to prevent hypertension.
A
Manipulation of the adrenal tumor in patients with pheochromocytoma can cause a massive catecholamine release. Alpha-adrenergic antagonists are given to reduce the risk of acute hypertension during surgery. These agents do not prevent secretion of catecholamines; they block catecholamine receptor sites. They do not act on the tissue of the adrenal medulla. They are given chronically in patients who have inoperable tumors.
A patient with type I diabetes is taking NPH insulin, 30 units every day. A nurse notes that the patient is also taking metoprolol (Lopressor). What education should the nurse provide to the patient?
a.
“Metoprolol has no effect on diabetes mellitus or on your insulin requirements.”
b.
“Metoprolol interferes with the effects of insulin, so you may need to increase your insulin dose.”
c.
“Metoprolol may mask signs of hypoglycemia, so you need to monitor your blood glucose closely.”
d.
“Metoprolol may potentiate the effects of the insulin, so the dose should be reduced.”
C
Because metoprolol may mask the signs of hypoglycemia, the patient should monitor the blood glucose closely and report changes to the prescriber. Metoprolol does have an indirect effect on diabetes mellitus and/or insulin requirements in that it may mask the signs of hypoglycemia, causing the patient to make a healthcare decision based on the drug-to-drug interaction rather than actual physiologic factors. The patient should not increase the insulin, because metoprolol will cause a decrease in blood glucose, increasing the risk of a hypoglycemic reaction. The patient should not reduce the dose of insulin when taking metoprolol, because this might alter serum glucose levels.
The nurse is discussing home management with a patient who will begin taking an alpha-adrenergic antagonist for hypertension. Which statement by the patient indicates understanding of the teaching?
a.
“I need to stop the medication if my heart rate increases.”
b.
“I should not drive while taking this medication.”
c.
“I should take the first dose at bedtime.”
d.
“I will stop taking the medication if I feel dizzy.”
C Orthostatic hypotension is a common side effect of this class of drugs and is most severe with the first dose. Administering the first dose at bedtime eliminates the risk associated with this first-dose effect. Tachycardia is an expected side effect; if severe, it can be treated with other medications. Patients should not drive during the first 12 to 24 hours after taking these agents, because fainting and dizziness may occur, but they may drive after that. Dizziness is not an indication for stopping the drug; patients who experience dizziness are instructed to sit or lie down until symptoms pass.
A nurse prepares to administer propranolol (Inderal) to a patient recovering from acute myocardial infarction. The patient’s heart rate is 52 beats per minute, and the rhythm is regular. What action should the nurse take next?
a.
Administer the drug as prescribed.
b.
Request an order for atropine.
c.
Withhold the dose and document the pulse rate.
d.
Withhold the dose and notify the prescriber.
D
A beta blocker, such as propranolol, should not be given if the pulse is lower than 60 beats per minute; therefore, the nurse should withhold the dose and notify the prescriber. Administering the dose as prescribed would not be appropriate, because the patient’s pulse rate is too slow at this time. The dose should be withheld and the prescriber notified. The patient’s heart rate is slow, and atropine may be necessary if the bradycardia persists, but the first step is to withhold the dose of propranolol. Withholding the dose and documenting the pulse rate is an appropriate but incomplete nursing intervention. The nurse must notify the prescriber to obtain further orders related to the medication.
A patient has benign prostatic hyperplasia (BPH) and will receive alfuzosin (Uroxatral). What is an important nursing action when administering this drug?
a.
Administer the first dose at bedtime to minimize the first-dose effect.
b.
Prepare the patient for potential ejaculatory dysfunction.
c.
Request an order for a diuretic to counter the effects of sodium retention.
d.
Review the patient’s chart for liver function tests (LFTs).
D
Alfuzosin is indicated for BPH only and is contraindicated in patients with moderate to severe hepatic impairment; therefore, LFTs would be an important assessment. It does not interfere with ejaculation. It does not reduce blood pressure and does not cause sodium retention or increased blood volume, so diuretics are not necessary. It does not cause orthostatic hypotension, so first-dose effect precautions are not necessary.
A nurse is discussing phentolamine (OraVerse) with a nursing student. Which statement by the student indicates the need for further teaching?
a.
“Phentolamine can be used to block both epinephrine- and norepinephrine-mediated vasoconstriction.”
b.
“Phentolamine can be used to treat pheochromocytoma.”
c.
“Phentolamine is a competitive adrenergic agonist that acts selectively on alpha1 receptors.”
d.
“Side effects of phentolamine may include tachycardia and hypotension.”
C
Phentolamine has actions on both alpha1 and alpha2 receptors; it is not selective for alpha1 receptors only. It blocks both epinephrine- and norepinephrine-mediated vasoconstriction. It is used to treat pheochromocytoma. Side effects include tachycardia and hypotension.
A patient taking a beta blocker complains of shortness of breath. The patient has respirations of 28 breaths per minute, a blood pressure of 162/90 mm Hg, and a pulse of 88 beats per minute. The nurse auscultates crackles in all lung fields. The nurse understands that these assessments are consistent with: a. bronchoconstriction. b. left-sided heart failure. c. rebound cardiac excitation. d. sinus bradycardia.
B
The signs and symptoms describe left-sided heart failure, in which the blood normally handled by the left ventricle and forced out through the aorta into the body backs up into the lungs, producing respiratory signs and symptoms. The patient’s signs and symptoms are not indicative of bronchoconstriction, which would cause wheezing and diminished breath sounds. Rebound cardiac excitation occurs when the beta blocker is withdrawn, not during administration of the drug. The patient’s heart rate is elevated, so sinus bradycardia is not present.
A male patient is being treated for benign prostatic hyperplasia and has stopped taking his alpha-adrenergic antagonist medication because of ejaculatory difficulties. Which medication does the nurse expect the provider to prescribe? a. Alfuzosin (Uroxatral) b. Prazosin (Minipress) c. Silodosin (Rapaflo) d. Tamsulosin (Flomax)
A
Alfuzosin is used for BPH and does not interfere with ejaculation. All of the other drugs have ejaculatory side effects. Prazosin may be useful for BPH, but it is not approved for this use.
A patient is taking a beta-adrenergic antagonist medication for angina pectoris and asks the nurse how the drug works to relieve the discomfort associated with this condition. Which statement by the patient after the nurse’s teaching indicates understanding of the drug’s effects?
a.
“It causes bronchodilation, which increases oxygen flow.”
b.
“It helps reduce the heart’s oxygen needs.”
c.
“It improves blood flow to the heart.”
d.
“It increases cardiac output.”
B
Blockade of beta1 receptors in the heart reduces cardiac work by reducing the heart rate, the force of contraction, and the velocity of impulse conduction through the AV node. Beta blockers result in bronchoconstriction, not bronchodilation. They do not increase blood flow to the heart. Cardiac output is decreased, not increased.
A nurse is caring for a newborn 1 day after delivery. The infant’s mother used betaxolol during pregnancy. The nurse will expect to monitor this infant for which condition? a. Hyperglycemia b. Hyperthyroidism c. Respiratory distress d. Tachycardia
C
Use of beta blockers during pregnancy can affect a newborn for several days after birth. Newborns are at risk for bradycardia, respiratory distress, and hypoglycemia. Hyperglycemia, hyperthyroidism, and tachycardia are not expected residual effects
A patient will begin taking propranolol (Inderal) for hypertension. Which statement by the nurse is important when teaching this patient about the medication?
a.
“Check your hands and feet for swelling and report that to your provider.”
b.
“It is safe to take this medication with a calcium channel blocker.”
c.
“Stop taking the drug if you become short of breath.”
d.
“Take your pulse and do not take the medication if your heart rate is fast.”
A
Patients taking propranolol can develop heart failure because of the suppression in myocardial contractility. Patients should be taught to watch for signs, which include shortness of breath, night coughs, and swelling of the extremities. Use of these agents with calcium channel blockers is contraindicated, because the effects are identical and excessive cardiosuppression can occur. Shortness of breath should be reported to the provider, but abrupt cessation of the drug can cause rebound cardiac excitability. Propranolol reduces the heart rate and should not be given if the pulse is less than 60 beats per minute.
A patient with migraines is started on a beta blocker. The nurse explains the benefits of taking the medication for migraines. Which statement by the patient indicates an understanding of the medication’s effects?
a.
“I need to take it every day to reduce the frequency of migraines.”
b.
“I will take it as needed to get relief from migraines.”
c.
“I will take it to shorten the duration of my migraines.”
d.
“I will take this drug when a migraine starts.”
A
When taken prophylactically, beta blockers can reduce the frequency of migraine attacks. Beta blockers do not provide complete relief from migraines. They do not reduce the duration of migraines. They are not effective for treating migraines once the migraine has begun.
Which are adverse effects of alpha blockade? (Select all that apply.) a. Hypertension b. Reflex tachycardia c. Nasal congestion d. Ejaculation e. Hypernatremia
B, C, E
Adverse effects of alpha blockade include reflex tachycardia, nasal congestion, and hypernatremia. Other adverse effects include orthostatic hypotension and inhibition of ejaculation. Hypertension and ejaculation are not adverse effects of alpha blockade.
A prescriber has ordered clonidine (Catapres) for a patient who has hypertension. The nurse teaches the patient about side effects of this drug. Which statement by the patient indicates understanding of the teaching?
a.
“I should chew sugar-free gum or drink water to reduce dry mouth.”
b.
“I should not drive as long as I am taking this drug.”
c.
“I should stand up slowly when taking this medication.”
d.
“I should stop taking this drug if I feel anxious or depressed.”
A
Xerostomia is a common side effect of clonidine and is often uncomfortable enough that patients stop using the drug. Counseling patients to chew sugar-free gum and take frequent sips of liquid can help alleviate this discomfort. Drowsiness is common, but this side effect becomes less intense over time. Patients should be counseled to avoid hazardous activities in the first weeks of therapy if they feel this effect. The hypertensive effects of clonidine are not posture dependent, as they are with the peripheral alpha-adrenergic blockers, so orthostatic hypotension is minimal with this drug. Clonidine causes euphoria, hallucinations, and sedation in high doses and can cause anxiety or depression, although the last two effects are less common. The drug should not be stopped abruptly because of the risk of rebound hypertension, so patients experiencing unpleasant central nervous system (CNS) effects should consult their provider about withdrawing the medication slowly.
A prescriber has ordered methyldopa for a patient with hypertension. The nurse teaches the patient about drug actions, adverse effects, and the ongoing blood tests necessary with this drug. The nurse is correct to tell the patient what?
a.
“If you have a positive Coombs’ test result, you will need to discontinue the medication, because this means you have hemolytic anemia.”
b.
“Methyldopa can be used for its analgesic effects and for its hypertensive effects.”
c.
“Xerostomia and orthostatic hypotension are serious side effects and indications for withdrawing the medication.”
d.
“You will need to contact the provider and stop taking the medication if your eyes look yellow.”
D
Hepatotoxicity is a serious adverse effect of methyldopa and is an indication for withdrawal of the drug to prevent fatal hepatic necrosis. Jaundice is a sign of liver toxicity. Patients should undergo periodic liver function tests while taking the drug. Liver function usually improves when the drug is withdrawn. A positive Coombs’ test result is not an indication for withdrawal of the drug in itself. About 5% of patients with a positive Coombs’ test result develop hemolytic anemia; withdrawal of the drug is indicated for those patients. Methyldopa does not have analgesic effects. Xerostomia and orthostatic hypotension are known side effects of methyldopa but usually are not serious.
A patient complains to the nurse that the clonidine (Catapres) recently prescribed for hypertension is causing drowsiness. Which response by the nurse to this concern is appropriate?
a.
“Drowsiness is a common side effect initially, but it will lessen with time.”
b.
“You may also experience orthostatic hypotension along with the drowsiness.”
c.
“You may be at risk for addiction if you have central nervous system side effects.”
d.
“You should discontinue the medication and contact your prescriber.”
A
CNS depression, evidenced in this patient by drowsiness, is common in about 35% of the population. These responses become less intense with continued drug use. Orthostatic hypotension is less likely with clonidine, because its antihypertensive effects are not posture dependent. The experience of drowsiness does not indicate abuse potential. The patient should not discontinue the medication abruptly because of the potential for rebound hypertension; the patient should contact the prescriber before stopping the medication.
A nurse is teaching nursing students about the pharmacology of methyldopa. Which statement by a student indicates the need for further teaching?
a.
“Methyldopa results in alpha2 agonist activation, but it is not itself an alpha2 agonist.”
b.
“Methyldopa is not effective until it is converted to an active compound.”
c.
“Methyldopa reduces blood pressure by reducing cardiac output.”
d.
“Methyldopa’s principal mechanism is vasodilation, not cardiosuppression.”
C
Methyldopa does not reduce the heart rate or cardiac output, so its hypotensive actions are not the result of cardiac depression. The drug is not, in itself, an alpha2 agonist. When taken up into brainstem neurons, it is converted into methylnorephinephrine, which is an alpha2 agonist; it is not effective until converted to this active compound. Its hypotensive effects are the result of vasodilation, not cardiosuppression.
A nurse is teaching a patient about a new prescription for reserpine (Serpasil) for hypertension. Which statement by the patient indicates the need for further teaching?
a.
“Depressive side effects are common and will improve over time.”
b.
“I should report gastrointestinal side effects to the provider.”
c.
“I should stand up slowly when getting up and lie down if I feel dizzy.”
d.
“Therapeutic effects may not be optimal for a couple of weeks.”
A
Reserpine can produce severe depression, which may persist for months during drug therapy and after the drug is withdrawn. Reserpine can stimulate the secretion of gastric acid, which can cause ulcers; it also can increase the tone and motility of intestinal smooth muscle, which can cause cramps and diarrhea. Reserpine can cause orthostatic hypotension, so patients should be counseled to rise slowly when standing up and to sit or lie down if they feel dizzy. Reserpine works by depleting norepinephrine, and the processes necessary for this may take 1 to 2 weeks.
A patient who has been taking clonidine (Catapres) for several weeks complains of drowsiness and constipation. What will the nurse do?
a.
Recommend that the patient take most of the daily dose at bedtime.
b.
Suggest asking the provider for a transdermal preparation of the drug.
c.
Suspect that the patient is overusing the medication.
d.
Tell the patient to stop taking the drug and call the provider.
A
CNS depression is common with clonidine, but this effect lessens over time. Constipation is also a common side effect. Patients who take most of the daily amount at bedtime can minimize daytime sedation. Transdermal forms of clonidine do not alter adverse effects. Patients who are abusing clonidine often experience euphoria and hallucinations along with sedation, but they generally find these effects desirable and would not complain about them to a healthcare provider. Clonidine should not be withdrawn abruptly, because serious rebound hypertension can occur.
A patient with hypertension has a previous history of opioid dependence. Which medication would the nurse question? a. Clonidine (Catapres) b. Guanabenz (Wytensin) c. Methyldopa d. Reserpine (Serpasil)
A
Patients who abuse cocaine, opioids, and other such drugs also frequently abuse clonidine, so this agent would not be the best choice for this patient. The other drugs do no share this abuse potential.