Sildenafil
Sildenafil is a prescription medication primarily used to treat erectile dysfunction in adult men. It works by inhibiting an enzyme called phosphodiesterase-5 (PDE5), which allows increased blood flow to the penis during sexual stimulation, helping to achieve and maintain an erection. The medication is also used to treat pulmonary arterial hypertension under the brand name Revatio.
Sildenafil is a medication that helps men with erectile dysfunction achieve and maintain erections by improving blood flow to the penis.
Key facts at a glance
- ATC
- G04BE03
- RxNorm
- 136411
- Generic
- Sildenafil
- Class
- atc-g04
- Brands
- Viagra, Liqrev, Vybrique, Revatio
- Availability
- rx
- Lactation
- unknown
- Routes
- oral
- Forms
- injection, suspension, tablet
- 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.
Dosage and administration
- Usual dose
- 50mg as needed
- Maximum
- consult physician
- Frequency
- approximately 1 hour before sexual activity, not more than once daily
- Instructions
- Follow physician instructions
- Duration limits
- as prescribed
- Monitoring
- standard
- Usual dose
- 10mg three times daily
- Maximum
- consult physician
- Frequency
- every 6-8 hours
- Instructions
- Follow physician instructions
- Duration limits
- as prescribed
- Monitoring
- standard
- Usual dose
- 25mg as needed
- Maximum
- consult physician
- Frequency
- approximately 1 hour before sexual activity, not more than once daily
- Instructions
- Follow physician instructions
- Duration limits
- as prescribed
- Monitoring
- standard
Overdose information
Special Populations
6 groupspregnancy
generalavoid use
avoid use during pregnancy unless benefits outweigh risks - primarily used for erectile dysfunction not indicated for pregnancy
regular fetal monitoring if used
Use of this medication in this population requires careful consideration of risks and benefits.
lactation
generalavoid if possible
sildenafil is excreted in breast milk - avoid breastfeeding during treatment
monitor infant for adverse effects
Use with caution and monitor for adverse effects.
geriatric
over 65start with lower dose
start at 25mg dose due to increased sensitivity and potential comorbidities
monitor blood pressure and cardiovascular status
Use with caution and monitor for adverse effects.
pediatric_age
under 18not recommended for erectile dysfunction
only use for pediatric pulmonary arterial hypertension under strict medical supervision - not for erectile dysfunction in minors
close monitoring for cardiovascular and developmental effects
Use with caution and monitor for adverse effects.
renal_impairment
severereduce dose to 25mg
reduce dose to 25mg with maximum 50mg dose in severe renal impairment - avoid in patients on dialysis
monitor renal function and blood pressure
Use with caution and monitor for adverse effects.
hepatic_impairment
moderate to severereduce dose to 25mg
reduce starting dose to 25mg in moderate hepatic impairment - use with extreme caution in severe hepatic impairment
monitor liver function and blood pressure
Use with caution and monitor for adverse effects.
Statistics and clinical data
FDA approval year
FDA approval for erectile dysfunction treatment
Drug class
Phosphodiesterase type 5 inhibitor classification
Common uses
Primary therapeutic indications
Brand names
marketed brand names for sildenafil
Sildenafil is primarily prescribed for erectile dysfunction (ED), the inability to get or keep an erection sufficient for satisfactory sexual performance. A higher-dose formulation is also used to treat pulmonary arterial hypertension (PAH), a condition characterized by high blood pressure in the lungs' arteries.
Sildenafil belongs to a class of drugs called phosphodiesterase-5 (PDE5) inhibitors. During sexual stimulation, nitric oxide is released in the penis, activating an enzyme that produces cyclic guanosine monophosphate (cGMP). This compound causes smooth muscle relaxation in the corpus cavernosum, allowing blood to flow in and create an erection. Sildenafil prevents PDE5 from breaking down cGMP, thereby prolonging its effects and enhancing erectile function.
Sildenafil does not cause sexual arousal and requires sexual stimulation to be effective. It should not be taken with nitrate medications or certain other drugs due to potentially dangerous blood pressure drops. Common side effects include headache, facial flushing, upset stomach, and nasal congestion. The medication should only be taken as prescribed by a healthcare provider, typically once daily before sexual activity. Those with certain heart conditions, recent stroke or heart attack, or low blood pressure should consult their doctor before use.
Contraindications
Conditions and patient states where this medication should be avoided or used with caution.
Do not use (1)
Known allergy to this medication or its components
Use caution (1)
Consult healthcare provider for benefits vs risks assessment
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 July 26, 2026. · Read our editorial policy