MTM Pharmacotherapy Review & Drug Interactions

Question 1

Which of the following medications is most likely to cause a serious drug interaction with warfarin?

Accepted Answer

Amiodarone

Answer

Amiodarone is a potent inhibitor of CYP2C9, the primary enzyme responsible for metabolizing warfarin. When taken together, amiodarone significantly increases warfarin's concentration in the blood, leading to an elevated risk of severe bleeding. Close monitoring and warfarin dose adjustments are critical when these medications are co-administered.

Question 2

What is the primary concern when combining an ACE inhibitor with a potassium-sparing diuretic?

Accepted Answer

Hyperkalemia

Answer

Both ACE inhibitors and potassium-sparing diuretics independently increase serum potassium levels. When these two drug classes are combined, their additive effects significantly elevate the risk of hyperkalemia, a dangerous condition characterized by excessively high potassium levels in the blood. This can lead to serious cardiac arrhythmias.

Question 3

Which medication is a strong CYP3A4 inhibitor that can increase serum levels of statins?

Accepted Answer

Ketoconazole

Answer

Ketoconazole is a strong inhibitor of the CYP3A4 enzyme, which is responsible for the metabolism of many statins (e.g., simvastatin, atorvastatin). By inhibiting this enzyme, ketoconazole prevents the breakdown of statins, leading to increased systemic exposure and higher serum levels. This significantly raises the risk of statin-related adverse effects, particularly myopathy and rhabdomyolysis.

Question 4

Which pharmacokinetic interaction occurs when omeprazole is taken with clopidogrel?

Accepted Answer

Reduced clopidogrel efficacy

Answer

Omeprazole, a proton pump inhibitor, inhibits the CYP2C19 enzyme, which is crucial for converting clopidogrel into its active antiplatelet metabolite. This inhibition reduces the activation of clopidogrel, thereby decreasing its antiplatelet efficacy. Consequently, patients taking both medications may have an increased risk of cardiovascular events like stent thrombosis.

Question 5

Which class of antidepressants is most associated with significant drug-drug interactions?

Accepted Answer

MAO inhibitors

Answer

Monoamine oxidase inhibitors (MAOIs) are known for their numerous and potentially severe drug-drug interactions due to their broad effects on neurotransmitter metabolism. They can lead to hypertensive crises when combined with tyramine-rich foods or sympathomimetic drugs, and cause life-threatening serotonin syndrome when co-administered with other serotonergic agents.

(MTM) Medication Therapy Management Board Certification Practice Test

(MTM) Medication Therapy Management Board Certification Practice Test

MTM Pharmacotherapy Review & Drug Interactions