Pharmacy PEBC Practice Exam

Which common drug interaction can increase the risk of bleeding when taken with warfarin?

1. Antibiotics

2. NSAIDs

3. Antidepressants

4. Diuretics

The correct answer is: NSAIDs

The correct answer is NSAIDs, as their interaction with warfarin is particularly significant when considering the risk of bleeding. Both NSAIDs and warfarin impact platelet function and affect the gastrointestinal mucosa, which can lead to an increased risk of gastrointestinal bleeding. NSAIDs, such as ibuprofen and naproxen, inhibit the enzyme cyclooxygenase (COX), which is essential for the synthesis of prostaglandins that help maintain the integrity of the gastric mucosa. When individuals on warfarin take NSAIDs, the added inhibition of platelet aggregation can exacerbate the anticoagulant effect of warfarin, compounding the risk of bleeding complications. In contrast, while antibiotics, antidepressants, and diuretics can have interactions with warfarin, their mechanisms do not typically lead to a direct increase in bleeding risk as prominently as NSAIDs. Some antibiotics may enhance the effects of warfarin due to alterations in gut flora or metabolic interactions, but this is less consistently associated with bleeding. Certain antidepressants, particularly SSRIs, have been noted to have some association with bleeding, but they do not have the same well-established risk as NSAIDs. Diuretics primarily affect fluid and electrolyte balance and are not significantly linked to