NCCPA Pharmacology 2 — Questions and Answers
Question 1: A patient on warfarin is started on fluconazole. What is the expected effect on INR?
- INR decreases due to enzyme induction
- INR increases due to CYP2C9 inhibition (Correct answer)
- INR is unchanged as there is no interaction
- INR decreases due to reduced warfarin absorption
Correct answer: INR increases due to CYP2C9 inhibition
Fluconazole inhibits CYP2C9, which metabolizes warfarin, leading to elevated warfarin levels and increased INR.
Question 2: Which beta-blocker is most cardioselective and preferred in a patient with reactive airway disease who requires beta-blockade?
- Propranolol
- Carvedilol
- Metoprolol succinate (Correct answer)
- Labetalol
Correct answer: Metoprolol succinate
Metoprolol succinate has the highest beta-1 selectivity among common beta-blockers, making it preferable in patients with reactive airway disease.
Question 3: A patient taking lithium develops polyuria and polydipsia. Which medication can reduce lithium-induced nephrogenic diabetes insipidus?
- Furosemide
- Amiloride (Correct answer)
- Hydrochlorothiazide
- Spironolactone
Correct answer: Amiloride
Amiloride blocks ENaC channels in collecting ducts, reducing lithium entry into renal tubular cells and alleviating nephrogenic DI.
Question 4: Which opioid analgesic is contraindicated in patients with renal failure due to accumulation of a toxic metabolite?
- Fentanyl
- Hydromorphone
- Meperidine (Correct answer)
- Methadone
Correct answer: Meperidine
Meperidine's metabolite normeperidine accumulates in renal failure and can cause seizures and CNS excitation.
Question 5: A patient on isoniazid develops peripheral neuropathy. What is the recommended treatment?
- Vitamin B12 supplementation
- Pyridoxine (vitamin B6) supplementation (Correct answer)
- Folate supplementation
- Thiamine supplementation
Correct answer: Pyridoxine (vitamin B6) supplementation
Isoniazid causes pyridoxine deficiency by inhibiting its activation, and supplementation with vitamin B6 prevents and treats peripheral neuropathy.
Question 6: Which class of antibiotics inhibits bacterial cell wall synthesis by binding to penicillin-binding proteins?
- Fluoroquinolones
- Macrolides
- Beta-lactams (Correct answer)
- Aminoglycosides
Correct answer: Beta-lactams
Beta-lactam antibiotics (penicillins, cephalosporins, carbapenems) bind to penicillin-binding proteins and inhibit transpeptidation of peptidoglycan.
Question 7: A patient with gout is started on allopurinol. What is its mechanism of action?
- Increases uric acid excretion by the kidney
- Inhibits xanthine oxidase, reducing uric acid synthesis (Correct answer)
- Blocks urate reabsorption in the proximal tubule
- Neutralizes uric acid crystals in joints
Correct answer: Inhibits xanthine oxidase, reducing uric acid synthesis
Allopurinol inhibits xanthine oxidase, the enzyme that converts hypoxanthine and xanthine to uric acid, thereby reducing uric acid production.
NCCPA Pharmacology 2
A patient on warfarin is started on fluconazole.
What is the expected effect on INR?