Moderate
Amlodipine × Sildenafil
Calcium channel blockers (dihydropyridines)×Phosphodiesterase type 5 inhibitors (PDE5)
Mechanism
Additive hypotension via different mechanisms – calcium channel blockade (amlodipine) + PDE5 blockade (sildenafil). Clinically significant in patients with prior hypotension.
Symptoms
Lower blood pressure, postural dizziness, fatigue. Older patients: fall risk.
Management
The combination is acceptable in stable hypertension. Take the first sildenafil dose lying down; do not exceed 25–50 mg. Warn the patient about orthostatic hypotension.
Check the full regimen, not just this pair
Opens the checker with these two drugs prefilled. Add the rest of the regimen and recompute additive risks.