Medically reviewed by Alan Lucks | MD, Alan Lucks MDPC Private Practice - New York on December 21st, 2025.
Sildenafil is a widely used medication best known for treating erectile dysfunction (ED) and pulmonary arterial hypertension (PAH). Understanding the right dosage is key to maximizing benefits while minimizing risks. This guide breaks down typical doses, timing, and adjustments to help you use sildenafil safely and effectively.
Sildenafil, a phosphodiesterase type 5 (PDE5) inhibitor, works by increasing blood flow to the penis, which helps achieve and maintain an erection in men experiencing erectile dysfunction. Its effectiveness has made it a popular choice since its introduction, and it is often the first medication prescribed for this condition. Beyond its use in erectile dysfunction, sildenafil has also gained attention for its role in treating pulmonary arterial hypertension, a serious condition characterized by high blood pressure in the lungs. By relaxing the blood vessels in the lungs, it helps improve exercise capacity and overall quality of life for those affected.
It is important to note that while sildenafil is effective, it is not suitable for everyone. Patients should be aware of potential side effects, which can include headaches, flushing, and gastrointestinal discomfort. More serious side effects, although rare, can occur, particularly in individuals with pre-existing cardiovascular conditions. Therefore, a thorough medical history and discussion of current medications with a healthcare provider are crucial before starting sildenafil. This ensures that the benefits outweigh any potential risks and that the patient is monitored appropriately throughout their treatment journey.
Form |
Strength |
Typical Adult Dose |
Typical Children’s Dose |
Frequency |
Route |
Maximum Daily Dose |
|---|---|---|---|---|---|---|
Tablet |
25 mg, 50 mg, 100 mg |
25-100 mg |
Not typically used |
Once daily (ED), three times daily (PAH) |
Oral |
100 mg (ED), 60 mg (PAH) |
Injection |
Varies (for PAH) |
As prescribed |
As prescribed |
Multiple times daily |
Intravenous |
As prescribed |
The typical starting dose for sildenafil in treating erectile dysfunction is 50 mg taken about one hour before sexual activity. Depending on effectiveness and tolerance, the dose can be adjusted to 25 mg or increased to a maximum of 100 mg. It should not be taken more than once per day.
Timing is important. Sildenafil works best when taken on an empty stomach, as food can delay its onset. Sexual stimulation is required for the medication to be effective.
For PAH, sildenafil is usually prescribed at a dose of 20 mg three times daily. This helps relax blood vessels in the lungs, improving blood flow and reducing blood pressure.
Unlike ED treatment, PAH dosing is consistent throughout the day and should be taken at evenly spaced intervals to maintain steady blood levels.
Adults using sildenafil for erectile dysfunction generally start at 50 mg per dose. Based on response and side effects, doctors may adjust this dose. The maximum recommended dose for ED is 100 mg per day.
For pulmonary arterial hypertension, adults typically take 20 mg three times daily. This regimen is designed to provide continuous relief from symptoms.
Sildenafil is less commonly used in children, but it may be prescribed for pediatric pulmonary arterial hypertension under close medical supervision. Dosages vary significantly based on weight and condition severity. It is critical to follow a healthcare provider’s guidance.
If you forget to take a dose of sildenafil prescribed for PAH, take it as soon as you remember, unless it is almost time for your next dose. Do not double up to make up for a missed dose.
For ED, sildenafil is typically taken as needed, so missing a dose usually does not apply. Avoid taking more than one dose in 24 hours.
Patients with liver or kidney problems may require lower doses of sildenafil. These organs process and clear the medication, so impaired function can increase drug levels in the body, raising the risk of side effects.
Sildenafil can interact with nitrates, certain blood pressure medications, and other drugs. These interactions may necessitate dosage adjustments or alternative treatments. Always inform your healthcare provider about all medications you are taking.
Taking more than the recommended dose of sildenafil can cause serious side effects, including severe hypotension, vision changes, and prolonged erections (priapism). If an overdose is suspected, seek emergency medical attention immediately.
Do not use sildenafil with nitrates or recreational drugs like “poppers” as this can cause dangerous drops in blood pressure.
Follow your healthcare provider’s instructions carefully.
Avoid alcohol and heavy meals before taking sildenafil to enhance effectiveness.
Store medication in a cool, dry place away from direct sunlight.
Do not take sildenafil more than once daily for ED.
Consult your doctor before combining sildenafil with other medications.
Personalized dosage advice is crucial for safe and effective use of sildenafil. Doctronic.ai offers free AI-driven consultations that synthesize the latest medical research to answer your questions quickly and accurately.
For more tailored guidance, Doctronic also provides affordable telehealth video visits with licensed doctors 24/7 across all 50 states. This service allows you to discuss your health, review medications, and get prescriptions if needed-all from the comfort of home.
Choosing the correct sildenafil dose depends on your condition, overall health, and how your body responds to the medication. Never self-adjust your dose without consulting a healthcare professional.
With Doctronic.ai, you can access modern, AI-powered medical expertise that remembers your history and provides personalized care whenever you need it.
For erectile dysfunction, sildenafil is usually taken as needed, not daily. For pulmonary arterial hypertension, it is taken regularly multiple times a day as prescribed.
Sometimes it takes a few tries to find the right dose or timing. Consult your healthcare provider or use telehealth services like Doctronic.ai to discuss your experience and adjust your treatment plan.
Not always. Sildenafil can interact with nitrates, blood pressure drugs, and certain other medications. Always inform your doctor about all medicines you take before starting sildenafil.
Sildenafil is not typically prescribed for women, except in rare cases for pulmonary arterial hypertension under strict medical supervision.
Side effects may include headache, flushing, nasal congestion, upset stomach, and dizziness. Serious side effects are rare but require immediate medical attention.
Always obtain sildenafil through a licensed healthcare provider or pharmacy. Telehealth services like Doctronic.ai can connect you with doctors who can prescribe sildenafil safely and legally.
Understanding Sildenafil Uses and DosagesSildenafil is a widely used medication best known for treating erectile dysfunction (ED) and pulmonary arterial hypertension (PAH). [...]
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