Drug Interactions MCQ Quiz | Clinical Pharmacology

1. A patient on long-term warfarin therapy is prescribed rifampicin for tuberculosis. What is the most likely interaction and its consequence?

2. Which of the following is a classic example of a pharmacodynamic synergistic interaction?

3. Grapefruit juice can significantly increase the plasma concentration of which of the following drugs by inhibiting CYP3A4?

4. A patient taking a tetracycline antibiotic should be advised to avoid concomitant administration of which of the following?

5. Co-administration of an NSAID (e.g., ibuprofen) with an ACE inhibitor (e.g., lisinopril) can lead to:

6. Serotonin syndrome is a potentially life-threatening condition that can result from combining an SSRI with which of the following?

7. The mechanism by which probenecid increases the serum concentration of penicillin is:

8. A patient on digoxin for heart failure develops hypokalemia due to concomitant use of a loop diuretic. This increases the risk of:

9. St. John’s Wort, an over-the-counter herbal supplement, is a potent inducer of CYP3A4. Its use can significantly decrease the efficacy of which of the following drugs?

10. A “cheese reaction” (hypertensive crisis) can occur if a patient taking an MAOI consumes tyramine-rich foods. This is an example of what type of interaction?

11. Cimetidine is a well-known inhibitor of several cytochrome P450 isoenzymes. It can increase the levels of which of the following drugs, potentially leading to toxicity?

12. Combining sildenafil with organic nitrates (e.g., nitroglycerin) is contraindicated because of the risk of:

13. A patient taking lithium for bipolar disorder is prescribed a thiazide diuretic for hypertension. This combination may lead to:

14. Allopurinol inhibits the enzyme xanthine oxidase. This will significantly increase the toxicity of which of the following drugs?

15. What is the primary mechanism of interaction between warfarin and sulfonamides (e.g., sulfamethoxazole)?

16. The co-administration of a statin (e.g., atorvastatin) with a fibrate (e.g., gemfibrozil) increases the risk of:

17. Which of the following drugs is a classic enzyme inducer, leading to decreased levels of many other drugs?

18. A patient on theophylline for asthma is started on ciprofloxacin for a urinary tract infection. What is the likely outcome?

19. The interaction between beta-blockers and verapamil can lead to what adverse effect?

20. Metronidazole can cause a disulfiram-like reaction when taken with:

21. An interaction at the level of drug distribution often involves:

22. Combining clopidogrel with omeprazole is generally discouraged because:

23. Which term describes an interaction where the combined effect of two drugs is less than the effect of either drug alone?

24. Taking quinidine with digoxin can lead to increased digoxin levels primarily because quinidine:

25. A patient on warfarin eats large quantities of green leafy vegetables. This will most likely: