What happens if you take Viagra (sildenafil) with nitroglycerin?
Taking Viagra (sildenafil) together with nitroglycerin can cause a dangerous drop in blood pressure. Nitroglycerin lowers blood pressure by increasing blood flow, and sildenafil can also lower blood pressure. Used together, the combined effect can lead to symptomatic hypotension (such as dizziness, fainting, or collapse) [1].
Why is the combination risky?
Sildenafil increases the effect of nitric oxide signaling in blood vessels, which is the same pathway nitroglycerin uses to relax blood vessels. That overlap can make blood pressure fall more than either medicine alone [1].
What do clinicians usually recommend?
Most prescribing information and cardiovascular guidance advise against using sildenafil with nitrates (including nitroglycerin) because of the hypotension risk [1]. If chest pain occurs and nitrates are needed, patients should seek urgent medical care rather than self-medicating with sildenafil [1].
What if nitroglycerin is needed for chest pain—can sildenafil be taken later?
The core safety issue is the timing between sildenafil and nitrate exposure. Because nitrates can be prescribed for acute angina, the practical advice is not to combine them and to treat nitrate-needed situations as an emergency decision point for a clinician [1]. (Exact safe timing depends on the specific sildenafil dose and clinical factors; follow the guidance on the sildenafil label or your clinician’s instructions [1].)
Are other heart medicines involved?
This specific concern is about nitrates (like nitroglycerin). Other antihypertensives or “blood pressure-lowering” drugs can also contribute to low blood pressure, but the highest-alert interaction is with nitrates when sildenafil is in the system [1].
Sources:
1. Drugs.com. “Sildenafil (Viagra) and Nitroglycerin Interactions.” https://www.drugs.com/drug-interactions/sildenafil-with-nitroglycerin-2061-0-2099-0.html