Unit 5, CNS Drugs Flashcards
When a patient with a lower back injury begins experiencing muscle spasms, the provider orders cyclobenzaprine 10mg three times a day. What information will the provider include when teaching this patient about this drug?
a. This drug carries some risk of developing hallucinations and psychotic symptoms.
b. This medication may cause your urine to turn brown, black, or dark green.
c. You may experience blurred vision, dry mouth, or constipation
d. You will need to have liver function tests performed while taking this medication.
C
Cyclobenzaprine has significant anticholinergic effects and patients should be warned about dry mouth, blurred vision, and constipation. Tizanidine, not cyclobenzaprine, can cause hallucinations and psychotic symptoms. Methocarbamol, not cyclobenzaprine, may turn urine brown, black, or green, which is a harmless side effect. Tizanidine and metaxalone, not cyclobenzaprine, can cause liver toxicity and require monitoring
A provider is considering prescribing tizanidine for a patient who is experiencing localized muscle spasms after an injury. What information in the patient’s health history will be concerning enough to the provider to warrant selecting a different drug?
a. Chronic 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. Baseline liver enzymes should be obtained before dosing a d 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.
A provider has prescribed dantrolene for the following patients. Which patient will the provider monitor most closely for risk of injury?
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 patient with cerebral palsy has severe muscle spasticity and muscle weakness which makes it difficult to take anything by mouth. The provider will prescribe and educate the patient on which medication for home therapy?
a. Baclofen
b. Dantrolene
c. Diazepam
d. Metaxalone
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 is, therefore, a good choice for patients who can not take medications by mouth. Dantrolene causes muscle weakness and must be given by mouth or intravenously, so it would not be a good option for this patient. Diazepam is not the first-line drug of choice. Metaxalone is used to treat localized muscle spasms caused by injury and is not used for cerebral palsy.
A patient with cerebral palsy who has been receiving baclofen for 3 months is admitted to the
hospital for evaluation of new-onset seizures. What assessment question will the provider ask
to help identify the most likely cause of these seizures?
a. “Have you taken any extra doses of baclofen?”
b. “Are you aware of the most common adverse effect of baclofen?”
c. “Did you know that seizures are an idiopathic response to baclofen?”
d. Have you missed any doses of baclofen?”
D
Baclofen does not appear to cause physical dependence, but abrupt discontinuation has been associated with adverse reactions. Abrupt withdrawal of oral baclofen can cause visual
hallucinations, paranoid ideation, and seizures and should be considered when a patient develops these symptoms. Seizures are not a symptom of baclofen toxicity.
A provider provides teaching for a patient with a newly diagnosed partial complex seizure disorder who will begin therapy with an antiepileptic drug (AED). Which statement by the patient indicates to the provider an understanding of the teaching?
a. “I may need to try several drugs before finding one is effective.”
b. “I will know that the drug is effective if I am seizure-free for two months.”
c. “Serious side effects may occur, and if they do, I should stop taking the medication.”
d. “When the drug level is 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 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 wtith therapeutic drug levels, because not all medications work for all patients.
A patient who has been taking an antiepileptic drug for several weeks reports little change in seizure frequency, what action will the provider take to provide effective care?
a. Ask the patient to complete a seizure frequency chart for the past few weeks.
b. Write an order for serum drug levels.
c. Reinforce to the patient the need to take the medications as prescribed.
d. 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. 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 provider counsels a patient who is prescribed phenytoin 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 who takes phenytoin for seizures asks the provider for a prescription for oral contraceptives. What recommendation will the provider make to help assure the effectiveness of the contraception method?
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 adhere strictly to oral contraceptive schedules because phenytoin causes birth defects.
d. She should not take oral contraceptives, because they reduce the effectiveness of phenytoin.
B
Because phenytoin can reduce the effects of oral contraceptives 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 with a seizure disorder has an appointment with you due to an increase in seizure frequency. The prescriber considers adding carbamazepine 100 mg twice daily to the patient’s medication regimen but notes that the patient is already taking lamotrigine 375 mg twice daily. What changes will the prescriber make to the patient’s medication regimen?
a. Reduce the carbamazepine dose to 50 mg twice daily.
b. Reduce the lamotrigine dose to 225 mg twice daily.
c. Increase the carbamazepine dose to 200 mg twice daily.
d. Increase the lamotrigine dose to 500 mg twice daily.
D
Carbamazepine induces hepatic drug-metabolizing enzymes and can increase the rate at which
lamotrigine is metabolized; therefore, the lamotrigine dosage will need to be increased.
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.
The patient who is on memantine therapy has a slight elevation in the creatinine clearance. What action will the provider take in response to this laboratory result?
a. Add sodium bicarbonate to the patient’s drug regimen.
b. Order a serum creatinine level to validate the creatinine clearance.
c. Discontinue the memantine.
d. Reduce the dose of memantine.
D
Patients with severe renal impairment may require discontinuation, but with a slight elevation, a dosage reduction is indicated.
Adding sodium bicarbonate would alkalinize the urine and
increase memantine levels, causing toxicity.
It is not necessary to discontinue or decrease the dose of the memantine with mild or moderate renal impairment.
A serum creatinine level is
less sensitive than creatinine clearance for monitoring renal function in older adults and it
cannot be used to validate creatinine clearance findings.
Which of the following are neurotransmitters of the CNS (choose all that apply).
a. Dopamine
b. Epinephrine
c. Acetylcholine
d. Norepinepherine
e. Seratonin
f. Histamines
ALL answers are correct.
Acetylcholine, Epinephrine, and Norepinephrine function as neurotransmitters in both the peripheral and central nervous systems.
Dopamine has some activity in the PNS but is primarily a CNS neurotransmitter
Seratonin and Histamines are neurotransmitters in the CNS only
CNS drugs have different effects when taken long-term compared to the initial effects they produce. This is due to:
a. Drug tolerance
b. Adaptations in the brain
c. Physical dependence
d. Changes in the permeability of the blood-brain barrier
B
The difference in the effect of drugs when taken long-term in comparison to the initial effects they produce is due to adaptations the brain makes in response to ongoing exposure to drugs. The adaptations are usually beneficial but sometimes can be detrimental.
An example of beneficial adaptive changes is Phenobarbital. Sedation is an initial effect that decreases over time along with the development of full seizure control.
Drug tolerance refers to a decreased drug response that occurs with prolonged use
Physical dependence is s state in which abrupt discontinuation of the drug will precipitate a withdrawal syndrome.
While certain drugs are able to cross the blood-brain barrier more easily than others, neither short nor long-term use of drugs alters the permeability of the blood-brain barrier.
An infant who receives a drug that does not produce CNS side effects in adults exhibits drowsiness and sedation. The nurse understands that this is because of differences in which physiologic system in infants and adults?
a. Blood-brain barrier
b. First-pass effect
c. Gastrointestinal absorption
d. Renal filtration
A
The blood-brain barrier is not fully developed at birth, making infants much more sensitive to CNS drugs than older children and adults. CNS symptoms may include sedation and drowsiness. The first-pass effect and GI absorption affect metabolism and absorption of drugs, and renal filtration affects elimination of drugs, all of which may alter drug levels
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.
