A 78-year-old female presents to your community pharmacy with a new prescription for tadalafil 5 mg daily for pulmonary arterial hypertension. Her current medications include amlodipine 10 mg daily for hypertension, furosemide 40 mg daily for edema, digoxin 0.125 mg daily for atrial fibrillation, and escitalopram 10 mg daily for depression. She states her blood pressure is usually around 110/70 mmHg. What is the most important counseling point for this patient regarding her new medication?

Question: A 78-year-old female presents to your community pharmacy with a new prescription for tadalafil 5 mg daily for pulmonary arterial hypertension. Her current medications include amlodipine 10 mg daily for hypertension, furosemide 40 mg daily for edema, digoxin 0.125 mg daily for atrial fibrillation, and escitalopram 10 mg daily for depression. She states her blood pressure is usually around 110/70 mmHg. What is the most important counseling point for this patient regarding her new medication?

Answer options:

• Take tadalafil exactly as prescribed, at the same time each day.
• Avoid grapefruit juice while taking tadalafil, as it can increase drug levels.
• Report any new or worsening vision changes immediately. ✅ Be aware of potential additive hypotensive effects with amlodipine.

Correct answer: Be aware of potential additive hypotensive effects with amlodipine.

Explanation: Tadalafil is a phosphodiesterase-5 inhibitor that can cause vasodilation and hypotension. Concomitant use with other antihypertensives, such as amlodipine, can lead to additive hypotensive effects, increasing the risk of dizziness or falls in elderly patients. This is a critical safety consideration.