Short answer: The Viagra label dose for most men is 50 mg taken as needed about 1 hour before sexual activity, though it may be taken 30 minutes to 4 hours before. It may be raised to 100 mg or lowered to 25 mg, at most once per day. A 25 mg start is considered after 65, with liver or severe kidney impairment, and with alpha-blockers or some other medicines.
This is what the FDA label says. Follow your prescriber. Your prescriber may use a different dose or pace than the label's standard schedule.
What Viagra is approved for: Viagra is a PDE5 inhibitor approved to treat erectile dysfunction (ED) (section 1). It is not indicated for use in women or children (sections 8.1, 8.4). Sildenafil is also sold as Revatio for pulmonary arterial hypertension, and the two are not taken together (section 5.7).
Source
VIAGRA (sildenafil citrate) tablets, for oral use, prescribing information and Patient Information. Viatris Specialty. DailyMed, version published February 13, 2026. DailyMed setid d905dc8d-917f-4ea3-a4ee-a1ecf6967d4e
Viagra is a tablet taken by mouth, as needed, about 1 hour before sexual activity, or anywhere from 30 minutes to 4 hours before. It comes in 25 mg, 50 mg and 100 mg tablets (sections 2.1 and 3).
It may be taken with or without food (section 2.2). The Patient Information says it may take a little longer to start working after a high-fat meal.
The maximum recommended dosing frequency is once per day (section 2.1).
The table below is the label's schedule, from the Dosage and Administration section. Numbers are copied exactly; the section is in brackets.
| Situation | Dose on the label |
|---|---|
| Most patients | 50 mg, as needed, approximately 1 hour before sexual activity (30 minutes to 4 hours before) |
| Dose range | May be increased to a maximum of 100 mg or decreased to 25 mg, based on effectiveness and toleration |
| How often | Maximum recommended dosing frequency is once per day |
| Taking an alpha-blocker | Stable on the alpha-blocker first; start Viagra at 25 mg |
| Taking ritonavir | 25 mg prior to sexual activity; maximum 25 mg within a 48 hour period |
| Strong CYP3A4 inhibitors (ketoconazole, itraconazole, saquinavir) or erythromycin | Consider a starting dose of 25 mg |
| Over 65, liver impairment, or severe kidney impairment (CrCl <30 mL/min) | Consider a starting dose of 25 mg |
| Nitrates in any form, or riociguat | Contraindicated |
Ritonavir raised sildenafil blood levels 11-fold, so with ritonavir the dose is 25 mg and no more than 25 mg in 48 hours. Saquinavir and erythromycin raised levels about 3-fold.
People over 65, with liver impairment such as cirrhosis, or with creatinine clearance under 30 mL/min had higher sildenafil levels, so a 25 mg starting dose is considered. No change is needed for mild or moderate kidney impairment (section 8.6).
For men already on an optimized Viagra dose, an alpha-blocker is started at its lowest dose, since stepping it up may lower blood pressure further.
After Viagra, it is unknown when nitrates can be given safely, even at 24 hours when sildenafil levels are much lower.
Viagra is taken as needed, and the label has no missed-dose instruction. It says not to take Viagra more than once a day (section 2.1 and Patient Information).
More on this: missed a dose of Viagra.
Sildenafil is also sold as Revatio for pulmonary arterial hypertension. The label says not to take Viagra with Revatio, other sildenafil products, other PDE5 inhibitors or other ED treatments.
In Dose Track you set up Viagra as a protocol with the dose and schedule your prescriber gave you. A protocol can hold dose steps, each with its own dose and length in days or weeks, so a step-up plan like the one on the label can be entered once and the app moves to the next step on its own. Reminders follow the schedule, and every dose is logged with the date and time, so you can see which step you are on and when your last dose was. The app follows what you enter; it does not choose or change a dose.
This page is what the FDA label says, in plain words. It is not medical advice. Follow your prescriber, and ask them or your pharmacist about anything here.