STOP — Contraindicated
FDA contraindication — absolutely do not combine. Sildenafil must not be used within 24 hours of any nitrate. No dose adjustment can make this safe.
Evidence level: STRONG
Viagra (sildenafil) and nitroglycerin together can cause a life-threatening drop in blood pressure. Both drugs widen blood vessels through similar mechanisms, and the combined effect can cause your blood pressure to drop so low that it becomes a medical emergency.
Sildenafil inhibits PDE5, increasing cGMP and causing vasodilation. Nitrates also increase cGMP via nitric oxide. Combined effect causes severe, potentially fatal hypotension. FDA sildenafil label contraindicates nitrate use.
NEVER take Viagra/sildenafil if you use nitroglycerin or any nitrate medication. If you have chest pain and have taken sildenafil in the past 24 hours, tell the paramedics immediately — they must NOT give you nitroglycerin.
Take Sildenafil and Nitroglycerin as prescribed by your healthcare provider. If both are taken daily, maintain consistent timing for each. Ask your pharmacist about optimal spacing — they have access to comprehensive interaction databases and can provide personalized timing guidance.
Higher risk for: elderly, those with liver or kidney impairment, polypharmacy (5+ medications), recent medication changes, or those with multiple chronic conditions. Consult your pharmacist for specific risk factors.
Severe dizziness, fainting, dangerously low blood pressure, rapid heartbeat (compensatory), chest pain, stroke symptoms, shock
Carry a medical alert noting sildenafil use. Discuss alternative ED treatments that do not interact with nitrates. If taking nitrates, discuss with cardiologist before any PDE5 inhibitor use.
Discuss safer alternatives with your healthcare provider. They can recommend substitutions based on your specific health goals while minimizing interaction risks. Always bring a complete list of everything you take to your appointments.
Viagra (sildenafil) and nitroglycerin together can cause a life-threatening drop in blood pressure. Both drugs widen blood vessels through similar mechanisms, and the combined effect can cause your blood pressure to drop so low that it becomes a medical emergency.
Take Sildenafil and Nitroglycerin as prescribed by your healthcare provider. If both are taken daily, maintain consistent timing for each. Ask your pharmacist about optimal spacing — they have access to comprehensive interaction databases and can provide personalized timing guidance.
Severe dizziness, fainting, dangerously low blood pressure, rapid heartbeat (compensatory), chest pain, stroke symptoms, shock
Discuss safer alternatives with your healthcare provider. They can recommend substitutions based on your specific health goals while minimizing interaction risks. Always bring a complete list of everything you take to your appointments.
Carry a medical alert noting sildenafil use. Discuss alternative ED treatments that do not interact with nitrates. If taking nitrates, discuss with cardiologist before any PDE5 inhibitor use.
Or browse the full interaction database (121,000+ pairs).