Ms. Evelyn Reed, a 72-year-old female weighing 60 kg, presents to your pharmacy for a prescription of fluconazole 150 mg single dose for a vaginal candidiasis. Her current medications include atorvastatin 20 mg daily, ramipril 5 mg daily, and warfarin 4 mg daily for atrial fibrillation (INR currently 2.3). Which of the following is the most appropriate action for the pharmacist to take?

Question: Ms. Evelyn Reed, a 72-year-old female weighing 60 kg, presents to your pharmacy for a prescription of fluconazole 150 mg single dose for a vaginal candidiasis. Her current medications include atorvastatin 20 mg daily, ramipril 5 mg daily, and warfarin 4 mg daily for atrial fibrillation (INR currently 2.3). Which of the following is the most appropriate action for the pharmacist to take?

Answer options:

• Dispense the fluconazole and advise Ms. Reed to monitor for signs of bleeding. ✅ Contact the prescriber to recommend an alternative antifungal such as nystatin vaginal suppositories.
• Dispense the fluconazole and advise Ms. Reed to increase her warfarin dose by 1 mg for the next 3 days.
• Dispense the fluconazole and recommend a follow-up INR in 2 weeks.

Correct answer: Contact the prescriber to recommend an alternative antifungal such as nystatin vaginal suppositories.

Explanation: Fluconazole is a potent inhibitor of CYP2C9, which is a primary enzyme metabolizing warfarin. Co-administration can significantly increase INR and the risk of bleeding. Recommending a topical or alternative antifungal that does not have this interaction, such as nystatin vaginal suppositories, is the safest approach.