Psychiatric-Mental Health Nurse Practitioner Exam Medications 4 — Questions and Answers
Question 1: A patient on carbamazepine for bipolar disorder develops diplopia, ataxia, and elevated carbamazepine levels despite no dose change. What is the most likely explanation?
- Carbamazepine autoinduction of CYP3A4 has reversed
- A new drug inhibited CYP3A4, raising carbamazepine levels (Correct answer)
- Renal failure reduced carbamazepine clearance
- The patient developed carbamazepine-induced hypothyroidism
Correct answer: A new drug inhibited CYP3A4, raising carbamazepine levels
Carbamazepine is metabolized by CYP3A4; adding a CYP3A4 inhibitor (e.g., erythromycin, fluconazole) raises carbamazepine levels and can precipitate toxicity.
Question 2: Which statement about lamotrigine dosing in the context of valproate co-administration is correct?
- Valproate induces lamotrigine metabolism, requiring higher lamotrigine doses
- Valproate inhibits lamotrigine glucuronidation, requiring slower titration and lower target doses (Correct answer)
- Valproate has no effect on lamotrigine pharmacokinetics
- Lamotrigine reduces valproate levels by 50%, requiring valproate dose increases
Correct answer: Valproate inhibits lamotrigine glucuronidation, requiring slower titration and lower target doses
Valproate inhibits UGT enzymes responsible for lamotrigine glucuronidation, doubling lamotrigine half-life; the combination requires halved lamotrigine doses and slower titration to prevent Stevens-Johnson syndrome.
Question 3: A 70-year-old patient with dementia-related psychosis is prescribed haloperidol. What critical warning must be communicated to the family?
- Haloperidol causes irreversible memory loss in elderly patients
- Antipsychotics are associated with increased mortality in elderly patients with dementia-related psychosis (Correct answer)
- Haloperidol must be stopped after 4 weeks to prevent dependence
- The drug requires mandatory REMS enrollment for patients over 65
Correct answer: Antipsychotics are associated with increased mortality in elderly patients with dementia-related psychosis
All antipsychotics carry a black box warning of increased mortality (primarily cardiovascular and infectious causes) when used in elderly patients with dementia-related psychosis.
Question 4: Which of the following describes the appropriate use of flumazenil in benzodiazepine overdose?
- It is the first-line treatment and should be given to all benzodiazepine overdose patients
- It should be avoided in patients with chronic benzodiazepine use due to risk of precipitating seizures (Correct answer)
- It provides sustained reversal lasting 8-12 hours, eliminating need for monitoring
- It reverses opioid co-ingestion as well, making it useful in mixed overdoses
Correct answer: It should be avoided in patients with chronic benzodiazepine use due to risk of precipitating seizures
Flumazenil can precipitate life-threatening withdrawal seizures in benzodiazepine-dependent patients and should be used cautiously; it is not routinely recommended in chronic users.
Question 5: A patient stabilized on sertraline begins rifampin for tuberculosis treatment. Which clinical outcome should the PMHNP anticipate?
- Elevated sertraline levels causing serotonin syndrome
- Reduced sertraline efficacy due to CYP3A4 and CYP2C19 induction (Correct answer)
- Increased QTc prolongation risk from the combination
- No clinically significant interaction between these agents
Correct answer: Reduced sertraline efficacy due to CYP3A4 and CYP2C19 induction
Rifampin is a potent inducer of multiple CYP enzymes including CYP3A4 and CYP2C19, significantly increasing sertraline metabolism and potentially causing recurrence of depression.
Question 6: What is the primary rationale for prescribing propranolol as an adjunct in a patient with performance anxiety (situational social anxiety)?
- Propranolol crosses the blood-brain barrier and directly reduces limbic hyperactivity
- Propranolol blocks peripheral beta-adrenergic receptors, reducing somatic symptoms like tremor and palpitations (Correct answer)
- Propranolol increases GABA activity in the cerebellum, reducing physiological arousal
- Propranolol inhibits norepinephrine synthesis at the adrenal medulla
Correct answer: Propranolol blocks peripheral beta-adrenergic receptors, reducing somatic symptoms like tremor and palpitations
Propranolol reduces the peripheral autonomic manifestations of anxiety (tremor, tachycardia, sweating) by blocking beta-1 and beta-2 adrenergic receptors without significant CNS sedation.
Question 7: A patient on venlafaxine for 2 years abruptly stops the medication. Which symptom cluster is most characteristic of what will occur within 24-48 hours?
- Rebound hypertension, diaphoresis, and fever consistent with adrenergic storm
- Dizziness, electric shock sensations ('brain zaps'), nausea, and irritability (Correct answer)
- Bradycardia, hypotension, and somnolence consistent with cholinergic excess
- Acute psychosis, hallucinations, and severe insomnia
Correct answer: Dizziness, electric shock sensations ('brain zaps'), nausea, and irritability
Venlafaxine has a short half-life and discontinuation syndrome (FINISH mnemonic) is common, characterized by flu-like symptoms, insomnia, nausea, sensory disturbances, and hyperarousal.
Psychiatric-Mental Health Nurse Practitioner Exam Medications 4
A patient on carbamazepine for bipolar disorder develops diplopia, ataxia, and elevated carbamazepine levels despite no dose change.
What is the most likely explanation?