Article
Who should not take viagra?
Anyone on nitrates must not take Viagra; caution also for severe heart disease, very low blood pressure and certain eye conditions.
Some people should not take Viagra: above all, anyone using nitrates for heart conditions, for whom the combination can cause a dangerous drop in blood pressure. Others — with severe heart disease, very low blood pressure, certain eye conditions or specific drug combinations — need caution or should avoid it. This article explains who should not take it and why a prescription matters.
It is a topic in our erectile dysfunction section.
The absolute no: nitrates
The most important rule is that Viagra must never be combined with nitrates (used for angina and chest pain). Together they can cause a severe, potentially fatal fall in blood pressure. This is an absolute contraindication and the main reason Viagra is prescription-only.
Heart and blood pressure
Men with serious or unstable heart disease, recent heart attack or stroke, or very low blood pressure should avoid Viagra or use it only after careful assessment. The question is whether the heart can safely handle both the drug and the exertion of sex.
| Group | Guidance |
|---|---|
| On nitrates | must not take it |
| Severe/unstable heart disease | avoid or assess carefully |
| Very low blood pressure | caution or avoid |
| Certain eye conditions | discuss with doctor |
Eye and other conditions
Men with a rare inherited eye disease (retinitis pigmentosa) or a history of sudden vision loss (NAION) should be cautious. Severe liver or kidney problems may require dose adjustment. These are reasons a doctor reviews your history before prescribing.
Drug interactions
Besides nitrates, alpha-blockers, some antifungals and HIV medicines can interact with Viagra, needing dose changes or avoidance. This is why disclosing every medicine and supplement to your doctor is essential. See alpha-blockers with Viagra.
The safe path
Because these risks are individual, only a doctor can confirm whether Viagra is safe for you. That is precisely what the prescription requirement protects against, and why buying without one is dangerous. For heart patients specifically, see Viagra after bypass surgery.
Alpha-blockers: alpha-blockers with Viagra. Heart bypass: Viagra after bypass. Side effects: how long side effects last.
Frequently asked questions
- Who should not take Viagra?
- Above all, anyone on nitrates; also those with severe heart disease, very low blood pressure or certain eye conditions.
- Why are nitrates so dangerous with it?
- Together they can cause a severe, potentially fatal drop in blood pressure.
- How do I know if it's safe for me?
- Only a doctor can confirm it, which is why a prescription is required.