Pharmacy Drug Interactions 2

Question 1

A patient on warfarin starts taking aspirin. What is the primary concern?

Accepted Answer

Increased risk of bleeding

Answer

Aspirin inhibits platelet aggregation and may displace warfarin from protein binding sites, significantly increasing bleeding risk when combined.

Question 2

Which drug, when combined with an SSRI, can cause serotonin syndrome?

Accepted Answer

Tramadol

Answer

Tramadol inhibits serotonin reuptake; combining it with SSRIs can lead to excessive serotonin accumulation, causing serotonin syndrome.

Question 3

Grapefruit juice is known to inhibit which enzyme, causing elevated plasma levels of many drugs?

Accepted Answer

CYP3A4

Answer

Grapefruit juice inhibits intestinal CYP3A4, reducing first-pass metabolism of many drugs (e.g., statins, calcium channel blockers), increasing their plasma concentrations.

Question 4

Concurrent use of an ACE inhibitor and a potassium-sparing diuretic increases the risk of:

Accepted Answer

Hyperkalemia

Answer

Both ACE inhibitors (reduce aldosterone) and potassium-sparing diuretics (block aldosterone or sodium channels) retain potassium, leading to dangerous hyperkalemia.

Question 5

Ciprofloxacin should not be taken within 2 hours of antacids containing aluminum or magnesium because:

Accepted Answer

Cations chelate ciprofloxacin, reducing absorption

Answer

Divalent and trivalent cations (Al³⁺, Mg²⁺, Ca²⁺, Fe²⁺, Zn²⁺) chelate fluoroquinolones, forming insoluble complexes that dramatically reduce oral absorption.

Pharmacy Practice Test

Pharmacy Practice Test

Pharmacy Drug Interactions 2