Sildenafil
Viagra (sildenafil) is a prescription medication primarily used to treat erectile dysfunction in adult men. It belongs to a class of drugs called phosphodiesterase type 5 (PDE5) inhibitors, which work by relaxing blood vessels and increasing blood flow to the penis during sexual stimulation.
Viagra is a PDE5 inhibitor used to treat erectile dysfunction by improving blood flow to the penis.
Key facts at a glance
- RxNorm
- 190465
- Generic
- Viagra
- Class
- brand-name
- Brands
- —
- Availability
- rx
- Lactation
- unknown
- Routes
- —
- Forms
- —
- Regions
- US, EU, CN, JP
- Monitoring
- —
This page is for informational purposes only.
Do not use this information to diagnose yourself or to replace a physician's advice. Always consult a qualified healthcare provider before starting, stopping, or changing any medication. If you believe you are experiencing a medical emergency, call your local emergency number immediately.
Viagra is indicated for the treatment of erectile dysfunction (ED) in adult men. It is also available in a different formulation (Revatio) for treating pulmonary arterial hypertension.
Viagra inhibits the enzyme phosphodiesterase type 5 (PDE5), which normally breaks down a substance called cyclic guanosine monophosphate (cGMP). By preventing this breakdown, cGMP levels increase, leading to smooth muscle relaxation in the blood vessels of the penis and improved blood flow. Sexual stimulation is required for the medication to be effective.
Viagra should not be taken with nitrates or certain other medications, as this can cause a dangerous drop in blood pressure. Common side effects may include headache, flushing, upset stomach, and visual changes. It should only be taken as prescribed by a healthcare provider, and men with certain heart conditions should consult their doctor before use. The medication does not protect against sexually transmitted infections or serve as contraception.
Official drug label
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This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment.
This content is for general informational and educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the guidance of a qualified healthcare provider with any questions you have about a medical condition, and never disregard professional medical advice or delay seeking it because of something you read here.
If you think you may have a medical emergency, call your local emergency number or go to the nearest emergency department immediately.
Medically reviewed by WellAlly Editorial Team Last reviewed August 26, 2026. · Read our editorial policy