Central Nervous System Drugs (Ch. 20-35+71) Flashcards
A psychiatric nurse is teaching a patient about an antidepressant medication. The nurse tells the patient that therapeutic effects may not occur for several weeks. The nurse understands that this is likely the result of:
a.
changes in the brain as a result of prolonged drug exposure.
b.
direct actions of the drug on specific synaptic functions in the brain.
c.
slowed drug absorption across the blood-brain barrier.
d.
tolerance to exposure to the drug over time.
A
It is thought that beneficial responses to central nervous system (CNS) drugs are delayed because they result from adaptive changes as the CNS modifies itself in response to prolonged drug exposure, and that the responses are not the result of the direct effects of the drugs on synaptic functions. The blood-brain barrier prevents protein-bound and highly ionized drugs from crossing into the CNS, but it does not slow the effects of drugs that can cross the barrier. Tolerance is a decreased response to a drug after prolonged use.
A nurse is teaching a group of nursing students how the CNS adapts to psychotherapeutic medications. Which statement by a nursing student indicates a need for further teaching?
a.
“Adaptation can lead to tolerance of these drugs with prolonged use.”
b.
“Adaptation helps explain how physical dependence occurs.”
c.
“Adaptation often must occur before therapeutic effects develop.”
d.
“Adaptation results in an increased sensitivity to side effects over time.”
D
With adaptation of the central nervous system to prolonged exposure to CNS drugs, many adverse effects diminish and therapeutic effects remain. Adaptation helps explain how tolerance and physical dependence occur, as the brain adapts to the presence of the drug. Therapeutic effects can take several weeks to manifest, because they appear to work by initiating adaptive changes in the brain.
A group of nursing students asks a nurse to explain the blood-brain barrier. The nurse would be correct to say that the blood-brain barrier:
a.
prevents some potentially toxic substances from crossing into the central nervous system.
b.
causes infants to be less sensitive to CNS drugs and thus require larger doses.
c.
allows only ionized or protein-bound drugs to cross into the central nervous system.
d.
prevents lipid-soluble drugs from entering the central nervous system.
A
The blood-brain barrier can prevent some drugs and some toxic substances from entering the CNS. The blood-brain barrier in infants is not fully developed, so infants are more sensitive to CNS drugs and often require lower doses. The blood-brain barrier prevents highly ionized and protein-bound drugs from crossing into the CNS and allows lipid-soluble drugs and those that can cross via specific transport systems to enter.
A nurse is teaching a group of students about how CNS drugs are developed. Which statement by a student indicates a need for further teaching?
a.
“Central nervous system drug development relies on observations of their effects on human behavior.”
b.
“Studies of new central nervous system drugs in healthy subjects can produce paradoxical effects.”
c.
“Our knowledge of the neurochemical and physiologic changes that underlie mental illness is incomplete.”
d.
“These drugs are developed based on scientific knowledge of CNS transmitters and receptors.”
D
The deficiencies in knowledge about how CNS transmitters and receptors work make systematic development of CNS drugs difficult. Testing in healthy subjects often leads either to no effect or to paradoxical effects. Medical knowledge of the neurochemical and physiologic changes underlying mental illness is incomplete. The development of CNS drugs depends less on knowledge of how the CNS functions and how these drugs effect that process and more on how administering one of these agents leads to changes in behavior.
A patient asks a nurse to explain what drug tolerance means. The nurse responds by telling the patient that when tolerance occurs, it means the patient:
a.
has developed a psychologic dependence on the drug.
b.
may need increased amounts of the drug over time.
c.
will cause an abstinence syndrome if the drug is discontinued abruptly.
d.
will have increased sensitivity to drug side effects.
B
When tolerance develops, a dose increase may be needed, because a decreased response may occur with prolonged use. Psychologic dependence involves cravings for drug effects and does not define tolerance. Physical dependence occurs when the drug becomes necessary for the brain to function “normally,” meaning the patient should be weaned from the drug slowly to prevent an abstinence syndrome. Patients may have a decreased sensitivity to drug side effects over time as the brain adapts to the medication.
Which monoamines act as neurotransmitters in the central nervous system? (Select all that apply.) a. Acetylcholine b. Norepinephrine c. Serotonin d. Dopamine e. Epinephrine f. Histamine
B, C, D, E
Acetylcholine and histamines are not monoamines.
A patient has taken levodopa (Dopar) for Parkinson’s disease for 2 weeks but reports no improvement in the symptoms. Which response by the nurse is correct?
a.
“Another agent will be needed to manage your symptoms.”
b.
“Double the dose to see whether an effect occurs.”
c.
“It may take several months for a response to occur.”
d.
“The prescriber may need to change your drug regimen.”
C
A full therapeutic response with levodopa may take several months to develop. Until the true effect of the dose is seen, it is not necessary to change to another drug, increase the dose, or change the drug regimen.
A nurse provides teaching for a patient who is newly diagnosed with Parkinson’s disease. Which statement by the patient indicates understanding of the drug therapy for this disease?
a.
“A levodopa/carbidopa combination is used to improve motor function.”
b.
“There are several drugs available to treat dyskinesias.”
c.
“When ‘off’ times occur, I may need to increase my dose of levodopa.”
d.
“With adequate drug therapy, the disease progression may be slowed.”
A
Levodopa combined with carbidopa is the initial drug of choice to treat motor symptoms. Amantadine is the only drug recommended to treat dyskinesias. Entacapone and rasagiline are used to treat abrupt loss of effect, or “off” times. Drug therapy does not slow the progression of the disease.
A patient has been diagnosed with Parkinson’s disease (PD) and begins treatment with levodopa/carbidopa (Sinemet). After several months of therapy, the patient reports no change in symptoms. The nurse will expect the provider to: a. add a dopamine agonist. b. discuss the “on-off” phenomenon. c. increase the dose of Sinemet. d. re-evaluate the diagnosis.
D
Patients beginning therapy with levodopa/carbidopa should expect therapeutic effects to occur after several months of treatment. Levodopa is so effective that a diagnosis of PD should be questioned if the patient fails to respond in this time frame. Adding a dopamine agonist is not indicated. The “on-off” phenomenon occurs when therapeutic effects are present. Increasing the dose of levodopa/carbidopa is not indicated.
A patient with Parkinson’s disease is taking levodopa/carbidopa (Sinemet) and reports occasional periods of loss of drug effect lasting from minutes to several hours. The nurse questions the patient further and discovers that these episodes occur at different times related to the medication administration. The nurse will contact the provider to discuss:
a.
administering a catechol-O-methyltransferase (COMT) inhibitor, such as entacapone.
b.
adding the DA-releasing agent amantadine to the regimen.
c.
giving a direct-acting dopamine agonist.
d.
shortening the dosing interval of levodopa/carbidopa.
A
This patient is describing abrupt loss of effect, or the “off” phenomenon, which is treated with entacapone or another COMT inhibitor. Amantadine is used to treat dyskinesias. A direct-acting dopamine agonist is useful for gradual loss of effect, which occurs at the end of the dosing interval as the dose is wearing off. Shortening the dosing interval does not help with abrupt loss of effect.
A patient newly diagnosed with Parkinson’s disease has been taking levodopa/carbidopa (Sinemet) for several weeks and complains of nausea and vomiting. The nurse tells the patient to discuss what with the provider?
a.
Taking a lower dose on an empty stomach
b.
Taking an increased dose along with a high-protein snack
c.
Taking a lower dose with a low-protein snack
d.
Taking dopamine in addition to levodopa/carbidopa
C
Because levodopa activates the chemoreceptive trigger zone (CTZ) of the medulla, causing nausea and vomiting (N/V), the patient may need to take a lower dose temporarily until tolerance develops. A meal helps slow absorption to minimize this side effect. A high protein intake contributes to abrupt loss of effect, so meals should be low in protein. Taking a dose on an empty stomach increases absorption and also N/V. An increased dose with a high-protein snack increases N/V and also abrupt loss of effect. Dopamine increases N/V, because it activates the CTZ of the medulla.
A nurse is discussing motor symptoms with a patient with Parkinson’s disease who has been taking levodopa/carbidopa (Sinemet) and who is now having regular tics. Which statement by the patient indicates understanding of this symptom?
a.
“I may need to try a lower dose of Sinemet to reduce my tics.”
b.
“My provider may order clozapine to treat these tics.”
c.
“These tics are an indication that my dose of Sinemet is too low.”
d.
“This means I will have to have surgery to stop the symptoms.”
A
Levodopa can cause movement disorders. If they occur, a lower dose of levodopa may be required to alleviate them. Clozapine is an antipsychotic used to treat levodopa-induced psychoses. Movement disorders generally occur as the dose of levodopa increases. Surgery is a last option for treating movement disorders, after amantadine fails.
A patient who has begun taking levodopa/carbidopa (Sinemet) reports feeling lightheaded and dizzy, especially when standing up from a sitting position. What will the nurse recommend?
a.
An alpha-adrenergic antagonist medication
b.
Discussing amantadine with the prescriber
c.
Increasing the salt and water intake
d.
Taking a drug holiday
C
Postural hypotension is common early in treatment and can be reduced by increasing the intake of salt and water. An alpha-adrenergic agonist, not an antagonist, can help. Amantadine is used to treat levodopa-induced dyskinesias. Drug holidays are used when adverse effects increase with long-term use of levodopa; the drug holiday allows beneficial effects to be achieved with lower doses, which reduces the incidence of side effects.
A nursing student wants to know why a patient who has been taking levodopa (Dopar) for years will now receive levodopa/carbidopa (Sinemet). The nurse explains the reasons that levodopa as a single agent is no longer available. Which statement by the student indicates a need for further education?
a.
“Carbidopa increases the availability of levodopa in the central nervous system.”
b.
“Carbidopa reduces the incidence of nausea and vomiting.”
c.
“Combination products reduce peripheral cardiovascular side effects.”
d.
“Combination products cause fewer dyskinesias and decreased psychosis.”
D
Adding carbidopa to levodopa does not reduce the incidence of dyskinesias or psychosis. In fact, carbidopa can increase the intensity and the speed of onset of these effects. Carbidopa inhibits decarboxylation of levodopa in the intestine and peripheral tissues, leading to more levodopa in the CNS. Carbidopa cannot cross the blood-brain barrier, so it does not have this action in the CNS. Peripheral side effects are reduced, including nausea, vomiting, and cardiovascular effects.
A nurse is teaching a group of nurses about Parkinson’s medications. The nurse is correct to state that one side effect associated with pramipexole (Mirapex) that is less likely to occur with other dopamine agonists is: a. sleep attacks. b. dizziness. c. hallucinations. d. dyskinesias.
A
A few patients taking pramipexole have experienced sleep attacks, or an overwhelming and irresistible sleepiness that comes on without warning. Dizziness, hallucinations, and dyskinesias are listed as side effects of pramipexole and other dopamine agonists.
A nursing student wants to know how carbidopa can be effective for treating Parkinson’s disease if it prevents the conversion of levodopa to dopamine. The nurse explains that carbidopa: a. can be taken with high-protein meals. b. does not cross the blood-brain barrier. c. has dopamine-like effects of its own. d. reduces abrupt loss of effect.
B
Carbidopa inhibits decarboxylation of levodopa in the intestine and peripheral tissues, leading to more levodopa in the CNS. Carbidopa cannot cross the blood-brain barrier, so it does not have this action in the CNS. Carbidopa is not given with high-protein meals. Carbidopa does not have dopamine-like effects. Carbidopa does not affect abrupt loss of effect.
A 25-year-old patient has been newly diagnosed with Parkinson’s disease, and the prescriber is considering using pramipexole (Mirapex). Before beginning therapy with this drug, the nurse will ask the patient about:
a.
any history of alcohol abuse or compulsive behaviors.
b.
any previous history of hypertension.
c.
difficulty falling asleep or staying asleep.
d.
whether any family members have experienced psychoses.
A
Pramipexole has been associated with impulse control disorders, and this risk increases in patients with a history of alcohol abuse or compulsive behaviors. Pramipexole increases the risk of hypotension and sleep attacks, so a history of hypertension or insomnia would not be cautionary. Unlike with levodopa, the risk of psychoses is not increased.
A hospitalized patient with Parkinson’s disease who is receiving apomorphine to treat “off” episodes develops nausea and vomiting. The nurse will discuss the use of which medication with the patient’s provider? a. Levodopa (Dopar) b. Ondansetron (Zofran) c. Prochlorperazine (Compazine) d. Trimethobenzamide (Tigan)
D
Trimethobenzamide can be used as an antiemetic in patients treated with apomorphine. Serotonin receptor agonists (e.g., ondansetron) and dopamine receptor antagonists (e.g., prochlorperazine) cannot be used, because they increase the risk of serious postural hypotension. Levodopa only increases nausea and vomiting.
A patient with Parkinson’s disease is taking levodopa/carbidopa (Sinemet). The prescriber orders bromocriptine (Parlodel) to treat dyskinesias. The nurse notes that the patient is agitated, and the patient reports having frequent nightmares. The nurse will contact the provider to discuss: a. adding an antipsychotic medication. b. changing from bromocriptine to cabergoline (Dostinex). c. reducing the dose of bromocriptine. d. reducing the dose of levodopa/carbidopa.
C
Bromocriptine is used to treat levodopa-induced dyskinesias and has dose-dependent psychologic side effects. The nurse should suggest reducing the dose of this drug to minimize these side effects. Adding an antipsychotic medication is not indicated. Cabergoline is not approved for this use. Reducing the dose of levodopa/carbidopa is not indicated.
A nurse is caring for an older adult man who has Alzheimer’s disease (AD). The patient’s daughter wants to know if testing can be done to determine her risk for developing the disease. What will the nurse tell her?
a.
Family history and female gender are both known to increase the risk.
b.
Genetic testing can provide a definitive measure of the risk.
c.
Patients with the apolipoprotein E2 gene (ApoE2) are more likely to develop the disease.
d.
Some biologic markers can be measured, but none is known to increase the risk.
D
Although several genes, proteins, and neurologic changes are associated with the presence of Alzheimer’s disease, none has been shown to have a direct causative link. Advancing age and a positive family history are the only two known risk factors. Female gender is not a known risk; the increased incidence among females may be the result of women living longer than men. No definitive genetic tests are available. The presence of ApoE2 seems to be protective.
The spouse of a patient who acts confused and forgetful wants to know if there is a test to determine whether the patient has Alzheimer’s disease. Which response by the nurse is correct?
a.
“A diagnosis is made by administering medications and observing for potential improvement in symptoms.”
b.
“The diagnosis is based on a patient’s age, family history, serum apolipoproteins, and genetic testing.”
c.
“Magnetic resonance imaging to demonstrate brain atrophy is the definitive test to determine Alzheimer’s disease.”
d.
“Proposed diagnostic criteria include measures of cognitive function and the presence of one known biomarker.”
D
In 2010 an international group of AD experts proposed revising diagnostic criteria to add the presence of at least one AD biomarker to current measures of cognitive function after a patient has been observed to have episodic memory impairment. The diagnosis currently is made by observing memory impairment and then measuring cognitive function. Most medications used for AD do not demonstrate sustained or unequivocal improvement, so they would not be useful for diagnostic purposes. The patient’s age and family history are risk factors. The serum ApoE level and genetic testing are not used to diagnose AD. Magnetic resonance imaging (MRI) can measure one brain marker of AD; however, brain atrophy has several different causes and is not definitive
An older adult patient with Alzheimer’s disease is admitted to the hospital. The patient’s spouse reports that the patient is often confused and gets lost walking to the store, which is 3 blocks from their home. That evening, the nurse observes the patient pacing the hall and screaming. What will the nurse do?
a.
Notify the provider of this patient’s worsening symptoms.
b.
Prepare the patient’s spouse for impending death from Alzheimer’s disease.
c.
Request an increase in the medication dose to treat the exacerbation in symptoms.
d.
Tell the spouse that this is an expected progression of the disease.
D
This patient is showing signs of the natural progression of AD. Behavior problems such as these occur in 70% to 90% of patients with AD as the disease progresses. There is no need to notify the provider to report these symptoms, because they are expected. The time from onset of symptoms to death usually is 4 to 8 years, but it may be as long as 20 years; this progression does not represent the final stages. Medications are not effective for preventing disease progression, and their effects on memory and cognition are modest, so requesting an increase in the drug dose would not help in this situation.
An older adult patient has confusion, memory loss, and disorientation in familiar surroundings. The patient has been taking donepezil (Aricept) 10 mg once daily for 6 months. The patient’s symptoms have begun to worsen, and the patient’s spouse asks if the medication dose can be increased. What will the nurse tell the spouse?
a.
The dose can be increased, because the patient has been taking the drug for longer than 3 months.
b.
The dose can be increased to twice daily dosing instead of once daily dosing.
c.
The increase in symptoms is the result of hepatotoxicity from the medication’s side effects.
d.
The patient must take the drug for longer than 1 year before the dose can be increased.
A
Donepezil is given for mild, moderate, and severe AD, and dosing may be increased, although it must be titrated up slowly. For patients with moderate to severe AD who have taken 10 mg once daily for at least 3 months, the dose can be increased to 23 mg once daily. Donepezil is not given twice daily. Donepezil does not cause hepatotoxicity; hepatotoxicity occurs with tacrine, the first acetylcholinesterase (AChE) inhibitor, which now is rarely used. Dosing is increased after 3 months, not 1 year.
A patient will begin taking a cholinesterase inhibitor for early Alzheimer’s disease. The nurse is teaching the patient’s spouse about the medication. Which statement by the spouse indicates a need for further teaching?
a.
“Gastrointestinal symptoms are common with this medication.”
b.
“People taking this drug should not take antihistamines.”
c.
“This drug helps neurons that aren’t already damaged to function better.”
d.
“This drug significantly slows the progression of the disease.”
D
Cholinesterase inhibitors produce modest improvements in cognition, behavior, and function and may slightly delay disease progression; they do not have a major impact on delaying progression of the disease. Gastrointestinal symptoms are common side effects. Drugs that block cholinergic receptors, including antihistamines, can reduce therapeutic effects and should be avoided. Cholinesterase inhibitors do not affect neurons already damaged, but they do improve function in those not yet affected.
The spouse of a patient with Alzheimer’s disease asks a nurse for more information about the rivastigmine (Exelon) transdermal patch that is being used. Which statement by the spouse indicates a need for further explanation?
a.
“Doses are lower but more steady with the transdermal patch.”
b.
“Reduced side effects occur with the transdermal patch.”
c.
“We only need to change the patch every 2 weeks.”
d.
“We should remove the old patch before applying the new one.”
C
The rivastigmine transdermal patch needs to be changed daily. Sites used should not be reused for 14 days. Transdermal dosing provides lower, steady levels of the drug. Intensity of side effects is lower with the transdermal patch. The old patch must be removed prior to applying the new patch to prevent toxicity.
A nurse is teaching a group of nursing students about the use of memantine (Namenda) for Alzheimer’s disease. Which statement by a student indicates understanding of the teaching?
a.
“Memantine is indicated for patients with mild to moderate Alzheimer’s disease.”
b.
“Memantine modulates the effects of glutamate to alter calcium influx into neurons.”
c.
“Memantine prevents calcium from leaving neurons, which improves their function.”
d.
“When used with donepezil, memantine increases the amount of calcium in neuronal cells.”
B
Memantine modulates the effects of glutamate, which is involved in calcium influx into neuronal cells. Memantine is used for patients with moderate to severe AD. Memantine does not prevent calcium from leaving cells; it only affects the influx of calcium. Although the effects of memantine and donepezil appear to be synergistic, the result is not always an increase in the amount of calcium in the cells.
A nurse is caring for an older adult patient who has Alzheimer’s disease. The patient is taking a cholinesterase inhibitor drug. Which side effects would concern the nurse? a. Confusion and memory impairment b. Dizziness and headache c. Nausea, vomiting, and diarrhea d. Slowed heart rate and lightheadedness
D
Cardiovascular effects of cholinesterase inhibitor drugs are uncommon but cause the most concern. Bradycardia and fainting can occur when cholinergic receptors in the heart are activated. Confusion and memory impairment are signs of the disease and are not side effects of the drug. Dizziness, headache, nausea, vomiting, and diarrhea are all expected adverse effects, and although uncomfortable, they do not present an increased risk to the patient.
A patient is worried about the risk of developing Alzheimer’s disease, because both parents had the disease. The nurse will tell this patient that known risk factors include what? (Select all that apply.) a. Advanced age b. Alcoholism c. Family history d. Gender e. Obesity
A, C
The major known risk factor for AD is advancing age; the only other known risk factor is a family history of AD. Alcoholism, gender, and obesity are not known risk factors.
A patient shows loss of consciousness, jaw clenching, contraction and relaxation of muscle groups, and periods of cyanosis. The nurse correctly identifies this as which type of seizure? a. Tonic-clonic b. Petit mal c. Myoclonic d. Atonic
A
Tonic-clonic seizures (or grand mal seizures) are considered generalized seizures and are manifested by a loss of consciousness, jaw clenching, muscle relaxation alternating with muscle contractions, and periods of cyanosis. Absence seizures (or petit mal seizures) are characterized by loss of consciousness for a brief period and usually involve eye blinking and staring into space. Myoclonic seizures consist of sudden contractions that may be limited to one limb or may involve the entire body. Atonic seizures are characterized by sudden loss of muscle tone.
A nurse is assessing a patient who becomes motionless and seems to stare at the wall and then experiences about 60 seconds of lip smacking and hand wringing. What should the nurse do?
a.
Ask the patient about a history of absence seizures.
b.
Contact the provider to report symptoms of a complex partial seizure.
c.
Notify the provider that the patient has had a grand mal seizure.
d.
Request an order for intravenous diazepam (Valium) to treat status epilepticus.
B
This patient showed signs of a complex partial seizure, characterized by impaired consciousness beginning with a period of motionlessness with a fixed gaze, followed by a period of automatism. The entire episode generally lasts 45 to 90 seconds. Absence seizures are characterized by loss of consciousness for a brief period (about 10 to 30 seconds) and may involve mild, symmetric motor activity or no motor signs. A grand mal seizure is characterized by jaw clenching and rigidity followed by alternating muscle relaxation and contraction and then periods of cyanosis, all with a loss of consciousness. Status epilepticus is a seizure that persists for 30 minutes or longer.
A nurse is discussing partial versus generalized seizures with a group of nursing students. Which statement by a student indicates understanding of the teaching?
a.
“Febrile seizures are a type of generalized tonic-clonic seizure.”
b.
“Generalized seizures are characterized by convulsive activity.”
c.
“Partial seizures do not last as long as generalized seizures.”
d.
“Patients having partial seizures do not lose consciousness.”
A
Febrile seizures typically manifest as a tonic-clonic seizure of short duration and are a type of generalized seizure. Generalized seizures may be convulsive or nonconvulsive. Partial seizures may last longer than some types of generalized seizures. Patients with complex partial seizures and secondarily generalized seizures, which are types of partial seizures, may lose consciousness.
A nurse provides teaching for a patient with a newly diagnosed partial complex seizure disorder who is about to begin therapy with antiepileptic drugs (AEDs). Which statement by the patient indicates understanding of the teaching?
a.
“Even with an accurate diagnosis of my seizures, it may be difficult to find an effective drug.”
b.
“I will soon know that the drugs are effective by being seizure free for several months.”
c.
“Serious side effects may occur, and if they do, I should stop taking the medication.”
d.
“When drug levels are maintained at therapeutic levels, I can expect to be seizure free.”
A
Even with an accurate diagnosis of seizures, many patients have to try more than one AED to find a drug that is both effective and well tolerated. Unless patients are being treated for absence seizures, which occur frequently, monitoring of the clinical outcome is not sufficient for determining effectiveness, because patients with convulsive seizures often have long seizure-free periods. Serious side effects may occur, but withdrawing a drug precipitously can induce seizures. Not all patients have seizure control with therapeutic drug levels, because not all medications work for all patients.
A nurse is caring for a patient who has been taking an antiepileptic drug for several weeks. The nurse asks the patient if the therapy is effective. The patient reports little change in seizure frequency. What will the nurse do?
a.
Ask the patient to complete a seizure frequency chart for the past few weeks.
b.
Contact the provider to request an order for serum drug levels.
c.
Reinforce the need to take the medications as prescribed.
d.
Request an order to increase the dose of the antiepileptic drug.
B
If medication therapy is not effective, it is important to measure serum drug levels of the medication to determine whether therapeutic levels have been reached and to help monitor patient compliance. Patients should be asked at the beginning of therapy to keep a seizure frequency chart to help deepen their involvement in therapy; asking for historical information is not helpful. Until it is determined that the patient is not complying, the nurse should not reinforce the need to take the medication. Until the drug level is known, increasing the dose is not indicated.
A patient with a form of epilepsy that may have spontaneous remission has been taking an AED for a year. The patient reports being seizure free for 6 months and asks the nurse when the drug can be discontinued. What will the nurse tell the patient?
a.
AEDs must be taken for life to maintain remission.
b.
Another AED will be substituted for the current AED.
c.
The provider will withdraw the drug over a 6- to 12-week period.
d.
The patient should stop taking the AED now and restart the drug if seizures recur.
C
The most important rule about withdrawing AEDs is that they should be withdrawn slowly over 6 weeks to several months to reduce the risk of status epilepticus (SE). AEDs need not be taken for life if seizures no longer occur. Substituting one AED for another to withdraw AED therapy is not recommended. Stopping an AED abruptly increases the risk of SE.
A patient with a seizure disorder is admitted to the hospital and has a partial convulsive episode shortly after arriving on the unit. The patient has been taking phenytoin (Dilantin) 100 mg three times daily and oxcarbazepine (Trileptal) 300 mg twice daily for several years. The patient’s phenytoin level is 8.6 mcg/mL, and the oxcarbazepine level is 22 mcg/mL. The nurse contacts the provider to report these levels and the seizure. What will the nurse expect the provider to order? a. A decreased dose of oxcarbazepine b. Extended-release phenytoin c. An increased dose of phenytoin d. Once-daily dosing of oxcarbazepine
C
This patient’s phenytoin level is low; the therapeutic range is 10 to 20 mcg/mL. An increase in the phenytoin dose is necessary. The oxcarbazepine level is within the normal range of 3 to 40 mcg/mL, so changing the dose is not necessary. Extended-release phenytoin is absorbed more slowly and would not increase this patient’s serum phenytoin level. The dosing of oxcarbazepine does not need to be changed.
A nurse counsels a patient who is to begin taking phenytoin (Dilantin) for epilepsy. Which statement by the patient indicates understanding of the teaching?
a.
“I should brush and floss my teeth regularly.”
b.
“Once therapeutic blood levels are reached, they are easy to maintain.”
c.
“I can consume alcohol in moderation while taking this drug.”
d.
“Rashes are a common side effect but are not serious.”
A
Gingival hyperplasia occurs in about 20% of patients who take phenytoin. It can be minimized with good oral hygiene, so patients should be encouraged to brush and floss regularly. Because small fluctuations in phenytoin levels can affect response, maintaining therapeutic levels is not easy. Patients should be cautioned against consuming alcohol while taking phenytoin. Rashes can be serious and should be reported immediately.
A patient is to begin taking phenytoin (Dilantin) for seizures. The patient tells the nurse that she is taking oral contraceptives. What will the nurse tell the patient?
a.
She may need to increase her dose of phenytoin while taking oral contraceptives.
b.
She should consider a different form of birth control while taking phenytoin.
c.
She should remain on oral contraceptives, because phenytoin causes birth defects.
d.
She should stop taking oral contraceptives, because they reduce the effectiveness of phenytoin.
B
Because phenytoin can reduce the effects of oral contraceptive pills (OCPs) and because avoiding pregnancy is desirable when taking phenytoin, patients should be advised to increase the dose of oral contraceptives or use an alternative method of birth control. Increasing the patient’s dose of phenytoin is not necessary; OCPs do not affect phenytoin levels. Phenytoin is linked to birth defects; OCPs have decreased effectiveness in patients treated with phenytoin, and the patient should be advised to increase the OCP dose or to use an alternative form of birth control. OCPs do not alter the effects of phenytoin.
A patient is admitted to the hospital for a new onset seizure disorder, and the prescriber orders carbamazepine (Tegretol). The nurse reviewing the patient’s medical history notes that the patient is taking warfarin. The nurse will contact the provider to discuss \_\_\_\_\_ dose. a. reducing the carbamazepine b. reducing the warfarin c. increasing the carbamazepine d. increasing the warfarin
D
Carbamazepine induces hepatic drug-metabolizing enzymes and can increase the rate at which it and other drugs are metabolized, including oral contraceptives and warfarin; therefore, patients taking any of these drugs would need an increased dose. Reducing the dose of either drug is not indicated. Increasing the dose of carbamazepine may be necessary but only after serum drug levels have been checked.
A patient who is taking oral contraceptives begins taking valproic acid (Depakote) for seizures. After a week of therapy with valproic acid, the patient tells the nurse that she is experiencing nausea. What will the nurse do?
a.
Ask the patient if she is taking the valproic acid with food, because taking the drug on an empty stomach can cause gastrointestinal side effects.
b.
Contact the provider to request an order for a blood ammonia level, because hyperammonemia can occur with valproic acid therapy.
c.
Suggest that the patient perform a home pregnancy test, because valproic acid can reduce the efficacy of oral contraceptives.
d.
Suspect that hepatotoxicity has occurred, because this is a common adverse effect of valproic acid.
A
Gastrointestinal effects, including nausea, vomiting, and indigestion, are common with valproic acid and can be minimized by taking the drug with food or using an enteric-coated product. Hyperammonemia can occur when valproic acid is combined with topiramate. Signs of pregnancy usually do not occur within a week, so this is less likely. Hepatotoxicity is a rare adverse effect.
A child is diagnosed with absence seizures, and the prescriber orders ethosuximide (Zarontin). When teaching the child’s parents about dosage adjustments for this drug, the nurse will stress the importance of:
a.
frequent serum drug level monitoring.
b.
learning as much as possible about the disorder and its treatment.
c.
recording the number of seizures the child has each day.
d.
reporting dizziness and drowsiness to the provider.
C
Measurements of plasma drug levels are less important than observation of seizure activity for determining effective dosages for absence seizures, because this type of seizure is characterized by as many as several hundred occurrences a day. Keeping a chart of seizure activity is the best way to monitor drug effectiveness when treating absence seizures. Frequent drug level monitoring is important when side effects occur to ensure that drug toxicity is not occurring. Learning about the disorder is an important part of adherence. Dizziness and drowsiness are common side effects that diminish with continued use.
A patient who has been taking phenobarbital for epilepsy begins taking valproic acid (Depakote) as adjunct therapy. The nurse notes that the patient is very drowsy. What will the nurse do?
a.
Explain to the patient that tolerance to sedation eventually will develop.
b.
Notify the prescriber, and request an order to reduce the dose of phenobarbital.
c.
Notify the prescriber of the need to increase the dose of valproic acid.
d.
Request an order for liver function tests to monitor for hepatotoxicity.
B
Valproic acid competes with phenobarbital for drug-metabolizing enzymes and can increase plasma levels of phenobarbital by approximately 40%. When this combination is used, the dose of phenobarbital should be reduced. Increasing the dose of valproic acid would compound the problem. Patients taking phenobarbital alone experience sedation, which diminishes as tolerance develops. Liver toxicity is a rare adverse effect of valproic acid and is marked by symptoms of nausea, vomiting, and malaise, not drowsiness
A nurse is providing teaching to a patient newly diagnosed with partial seizures who will begin taking oxcarbazepine (Trileptal). The patient also takes furosemide (Lasix) and digoxin (Lanoxin). Which statement by the patient indicates understanding of the teaching?
a.
“I may need to increase my dose of Trileptal while taking these medications.”
b.
“I may develop a rash and itching, but these are not considered serious.”
c.
“I should report any nausea, drowsiness, and headache to my provider.”
d.
“I should use salt substitutes instead of real salt while taking these drugs.”
C
Oxcarbazepine can cause clinically significant hyponatremia in 2.5% of patients. If oxcarbazepine is combined with other drugs that reduce sodium, the patient should be monitored. Signs of hyponatremia include nausea, drowsiness, confusion, and headache, and patients should be taught to report these symptoms. Increasing the dose of oxcarbazepine is not indicated. Rashes can indicate a serious drug reaction, and providers should be notified so that the oxcarbazepine can be withdrawn. Salt substitutes would compound the problem of hyponatremia.
A child who receives valproic acid (Depakote) begins taking lamotrigine (Lamictal) because of an increase in the number of seizures. The nurse will observe this child closely for which symptom? a. Angioedema b. Hypohidrosis c. Rash d. Psychosis
C
Lamotrigine can cause life-threatening rashes, such as Stevens-Johnson syndrome and toxic epidermal necrolysis, and this risk increases with concurrent use of valproic acid. Angioedema is an adverse effect associated with pregabalin. Hypohidrosis and psychosis are associated with topiramate.
A nurse is completing a discharge plan for a 24-year-old patient who will begin taking phenytoin. Which information is important to teach this patient?
a.
She may stop taking the drug when she is seizure free for a year.
b.
Taking the medication will ensure that she no longer has seizures.
c.
She may need to discontinue the drug if serious side effects occur.
d.
She should be sure to use an effective contraceptive method.
D
Because antiepileptic drugs can harm a fetus, female patients of childbearing age should be counseled about the use of contraceptives, which may also have drug-to-drug interactions with the antiepileptic drugs. Patients should be counseled that withdrawal of a seizure medication should be done only with the advice of their prescriber and not just when a certain period of time has passed without seizures. Taking a seizure medication is not a guarantee that seizures will not occur; managing seizures often requires experimenting with several different medications. Patients should report side effects and, if they are serious, should discontinue a drug but only under the guidance of their prescriber.
A nurse is admitting a patient to the hospital. The patient reports taking oral baclofen (Lioresal) but stopped taking the drug the day before admission. The nurse would be correct to anticipate which adverse effects? a. Weakness and dizziness b. Fatigue and drowsiness c. Seizures and hallucinations d. Respiratory depression and coma
C
Abrupt discontinuation of baclofen is associated with visual hallucinations, paranoid ideation, and seizures. Central nervous system effects of baclofen include weakness, dizziness, fatigue, and drowsiness. Respiratory depression is a result of overdose of baclofen.
A patient has localized muscle spasms after suffering a leg injury in sports. Treatment options for this patient will not include: a. analgesic anti-inflammatory drugs. b. chlorzoxazone (Paraflex). c. metaxalone (Skelaxin). d. whirlpool baths.
B
Chlorzoxazone is a centrally acting muscle relaxant; however, its hepatic side effects can be severe and life threatening, and its effectiveness is minimal, so the risks of using this agent outweigh the benefits. Analgesic anti-inflammatory drugs are used as part of drug therapy in a patient with muscle spasms caused by localized muscle injury. Metaxalone is a centrally acting muscle relaxant that can be used with caution and with periodic liver function evaluation. Whirlpool baths are useful adjuncts to drug therapy.
A nurse is caring for a patient receiving intrathecal baclofen (Lioresal). The patient is unresponsive. After asking a coworker to contact the provider, the nurse anticipates performing which intervention? a. Preparing to support respirations b. Administering an antidote to baclofen c. Administering diazepam to prevent seizures d. Obtaining an electrocardiogram
A
An overdose of baclofen can produce coma and respiratory depression, so the nurse would be correct to suspect overdose in this patient. Respiratory support is essential to prevent a fatal outcome. There is no antidote for baclofen overdose. Diazepam would not be indicated, because seizures are not a result of baclofen overdose and may further depress respirations. An electrocardiogram is not indicated for this patient.
A patient has localized muscle spasms after an injury. The prescriber has ordered tizanidine (Zanaflex) to alleviate the spasms. When obtaining the patient’s health history, the nurse should be concerned about which of the following as a possible reason for considering another drug? a. Concomitant use of aspirin b. A history of hepatitis c. A history of malignant hyperthermia d. Occasional use of alcohol
B
Hepatotoxicity is a serious potential problem in a patient receiving tizanidine, because the drug can cause liver damage. Baseline liver enzymes should be obtained before dosing and periodically thereafter. Analgesic anti-inflammatory drugs commonly are used in conjunction with centrally acting muscle relaxants, so using aspirin is not a concern. This drug does not contribute to malignant hyperthermia. Patients should be advised to avoid alcohol when taking this drug, but a history of occasional alcohol use is not a contraindication.
Which patient should receive dantrolene (Dantrium) with caution?
a.
A 20-year-old woman with a spinal cord injury
b.
A 45-year-old man with a history of malignant hyperthermia
c.
A 55-year-old woman with multiple sclerosis
d.
An 8-year-old child with cerebral palsy
C
Dose-related liver damage is the most serious adverse effect of dantrolene and is most common in women older than 35 years. Dantrolene is used to treat spasticity associated with multiple sclerosis, cerebral palsy, and spinal cord injury, so all of these patients would be candidates for this agent. Dantrolene also is used to treat malignant hyperthermia.
A nurse is teaching the parent of a child with spastic quadriplegia about intrathecal baclofen (Lioresal). Which statement by the parent indicates a need for further teaching?
a.
“I can expect my child to be more drowsy when receiving this medication.”
b.
“I should not notice any change in my child’s muscle strength.”
c.
“I will contact the provider if my child is constipated or cannot urinate.”
d.
“If my child has a seizure, I should stop giving the medication immediately.”
D
Seizures may occur if oral baclofen is withdrawn abruptly; seizures are not an adverse effect of baclofen. If intrathecal baclofen is stopped abruptly, patients can experience life-threatening effects, so parents should be advised not to stop the drug abruptly. The central nervous system effects of baclofen include drowsiness and lethargy, so these effects are expected. Baclofen does not reduce muscle strength. It can cause constipation and urinary retention, and patients should be advised to contact their provider so that these conditions can be treated.
A patient with cerebral palsy has severe muscle spasticity and muscle weakness. The patient is unable to take anything by mouth. The nurse is correct to anticipate that which medication will be ordered for home therapy? a. Baclofen (Lioresal) b. Dantrolene (Dantrium) c. Diazepam (Valium) d. Metaxalone (Skelaxin)
A
Baclofen is used to treat muscle spasticity associated with multiple sclerosis, spinal cord injury, and cerebral palsy. It does not reduce muscle strength, so it will not exacerbate this patient’s muscle weakness. It can be given intrathecally, via an implantable pump, and therefore is a good choice for patients who cannot take medications by mouth. Dantrolene must be given by mouth or intravenously and so would not be a good option for this patient. It also causes muscle weakness. Diazepam is not the first-line drug of choice. Alternative routes to PO administration are IM, IV, or by rectum. Metaxalone is used to treat localized muscle spasms caused by injury and is not used for cerebral palsy.
A patient with multiple sclerosis needs pharmacologic treatment for spasticity in order to begin strengthening exercises to improve walking ability. The nurse anticipates that which medication will be ordered for spasticity? a. Baclofen (Lioresal) b. Dantrolene (Dantrium) c. Diazepam (Valium) d. Metaxalone (Skelaxin)
A
Baclofen is used to treat spasms associated with multiple sclerosis. It has no direct muscle relaxant effects, so it does not reduce muscle strength. Dantrolene works well to reduce spasms, but it also has significant effects on muscle strength. Diazepam is not the first-line drug of choice, but it could be used because it does not reduce muscle strength. Metaxalone is not indicated to treat spasms caused by multiple sclerosis.
A nurse is teaching a patient who has a second-degree burn on one arm about the use of a topical anesthetic for pain. Which statement by the patient indicates understanding of the teaching?
a.
“I will apply a thin layer of the medication to a small area of skin.”
b.
“I will cover the burn with a dressing after applying the medication.”
c.
“I will make sure to apply the medication to the entire burn area.”
d.
“I will use the medication only on the most painful, blistered areas.”
A
Topical anesthetics can be absorbed in sufficient amounts to cause serious and even life-threatening systemic toxicity, so they should be applied in the smallest amount needed to as small an area as possible. Covering the site increases the skin’s temperature, which increases absorption, so this should be avoided. Applying the medication to a large area increases systemic absorption. Applying the medication to broken skin increases systemic absorption.
A nurse is discussing the use of cocaine as a local anesthetic with a nursing student. Which statement by the student indicates understanding of this agent?
a.
“Anesthetic effects develop slowly and persist for several hours.”
b.
“Cocaine is a local anesthetic administered by injection.”
c.
“Vasoconstrictors should not be used as adjunct agents with this drug.”
d.
“When abused, cocaine causes physical dependence.”
C
Cocaine should not be combined with epinephrine or other vasoconstrictors, because it causes vasoconstriction itself, and the combination could precipitate severe hypertension. Cocaine has a rapid onset of effects, which last about 1 hour. It is used only topically for anesthesia. Although subject to widespread abuse with profound psychologic dependence, it does not cause substantial physical dependence.
A nurse is assisting a physician who is preparing to suture a superficial laceration on a patient’s leg. The physician asks the nurse to draw up lidocaine with epinephrine. The nurse understands that epinephrine is used with the lidocaine to:
a.
allow more systemic absorption to speed up metabolism of the lidocaine.
b.
increase the rate of absorption of the lidocaine.
c.
improve perfusion by increasing blood flow to the area.
d.
prolong anesthetic effects and reduce the risk of systemic toxicity from lidocaine.
D
Epinephrine causes vasoconstriction, which reduces local blood flow and delays systemic absorption of lidocaine, which prolongs local anesthetic effects and reduces the risk of systemic toxicity. Epinephrine slows the rate of absorption. Epinephrine delays systemic absorption of lidocaine, so metabolism is slowed and the effects are prolonged in the periphery. Epinephrine does not increase local blood flow.
A nurse is assisting the physician during a procedure in which a local anesthetic is administered. Within a few minutes of administration of the anesthetic, the patient has a pulse of 54 beats per minute, respirations of 18 breaths per minute, and a blood pressure of 90/42 mm Hg. The nurse should monitor the patient for further signs of: a. heart block. b. anaphylaxis. c. central nervous system excitation. d. respiratory depression.
A
When absorbed in a sufficient amount, local anesthetics can affect the heart and blood vessels. These drugs suppress excitability in the myocardium and conduction system and can cause hypotension, bradycardia, heart block, and potentially cardiac arrest. Anaphylaxis would be manifested by hypotension, bronchoconstriction, and edema of the glottis. Central nervous system excitation would be manifested by hyperactivity, restlessness, and anxiety and may be followed by convulsions. No evidence indicates respiratory depression; this patient’s respirations are within normal limits.
A nurse is caring for a patient in the immediate postoperative period after surgery in which a spinal anesthetic was used. The patient has not voided and complains of headache. The patient has a pulse of 62 beats per minute, a respiratory rate of 16 breaths per minute, and a blood pressure of 92/48 mm Hg. Which action by the nurse is appropriate?
a.
Contact the anesthetist to request an order for ephedrine.
b.
Have the patient sit up to relieve the headache pain.
c.
Lower the head of the bed to a 10- to 15-degree head-down position.
d.
Obtain an order for a urinary catheter for urinary retention.
C
Spinal anesthetics have several adverse effects, but the most significant is hypotension caused by the venous dilation that occurs from blockade of sympathetic nerves. The result is decreased blood return to the heart, which causes reduced cardiac output and a drop in blood pressure. The first step in treating this is to put the patient in a 10- to 15-degree head-down position to promote venous return to the heart. Ephedrine or phenylephrine is used if the first measure fails. Spinal headaches are common; the intervention for this is to have the patient assume a supine position. Urinary retention can occur secondary to autonomic blockade; it is a concern if the patient has not voided for 8 hours after the procedure, but not in the immediate postoperative period.
A patient receives an epidural anesthetic during labor and delivery. The nurse caring for the newborn in the immediate postpartum period will observe the infant for: a. bradycardia. b. hypoglycemia. c. jitteriness. d. tachypnea.
A
Local anesthetics can cross the placenta, causing bradycardia and central nervous system (CNS) depression in the infant. They do not affect blood glucose. Jitteriness is a sign of CNS excitation. Increased respirations are not an adverse effect in the newborn.
A nurse is preparing a patient to go home from the emergency department after receiving sutures for a laceration on one hand. The provider used lidocaine with epinephrine as a local anesthetic. Which symptom in this patient causes the most concern?
a.
Difficulty moving the fingers of the affected hand
b.
Inability to feel pressure at the suture site
c.
Nervousness and tachycardia
d.
Sensation of pain returning to the wound
C
Absorption of the vasoconstrictor can cause systemic effects, including nervousness and tachycardia. If severe, alpha- and beta-adrenergic antagonists can be given. Local anesthetics are nonselective modifiers of neuronal function and also can block motor neurons, so it is expected that patients may have difficulty with movement. The sensation of pressure also is affected and is an expected effect. As the local anesthetic wears off, the sensation of pain will return.
