Sildenafil (Viagra): what it does and what to watch for
Sildenafil—best known by the brand name Viagra—helps many men get and keep an erection when there's sexual stimulation. It won’t cause arousal by itself, but it can restore function that’s been affected by health issues, stress, or age. If you’re reading up because you’re considering it, here’s what really matters: how to use it safely, how it acts, and how to avoid fakes or bad advice online.
How sildenafil works and common dosing basics
Sildenafil relaxes blood vessels in the penis so blood flows in more easily during arousal. Typical doses are 25 mg, 50 mg, or 100 mg taken 30–60 minutes before sex. Start low—many people try 50 mg first, then adjust with their doctor. Don’t take more than one dose in 24 hours. Food—especially a heavy, fatty meal—can slow how quickly it kicks in, so taking it on a lighter stomach often works better.
Men with certain health issues (heart disease, low blood pressure, kidney or liver problems) may need lower doses. If you use nitrates for chest pain or certain recreational drugs, sildenafil can dangerously lower your blood pressure. That combination is a hard no—tell your prescriber about all meds and supplements you use.
Side effects, interactions, and safety flags
Most side effects are mild and short-lived: headache, flushing, nasal congestion, upset stomach, or vision changes (blue tinge or blurred vision). If you get sudden hearing loss, chest pain, or an erection lasting longer than four hours (priapism), seek emergency help. Those are rare but serious.
Drug interactions matter. Besides nitrates, strong CYP3A4 inhibitors like some antifungals and HIV meds can raise sildenafil levels. Your doctor can adjust the dose. Also be cautious with alpha-blockers for prostate issues—taking both can cause lightheadedness or fainting.
If you’re buying sildenafil online, prefer pharmacies that ask for a prescription, show real contact details, and display some accreditation or licensing info. Avoid sites that sell without a prescription, offer suspiciously low prices, or won’t provide a pharmacist contact. When in doubt, check our guides on buying ED meds and read the Viagra Professional overview for more specifics.
Alternatives include other PDE5 inhibitors (like tadalafil or vardenafil) that differ in how long they last and how fast they work. For premature ejaculation or other sexual concerns, there are different meds and behavioral approaches—see articles on Priligy alternatives and Duratia for options and trade-offs. Remember: a pill isn’t the whole solution if anxiety, relationship issues, or health problems are the real cause.
Final practical tips: talk openly with your doctor, start with the lowest effective dose, avoid mixing with nitrates, store tablets in a cool dry place, and buy from reputable sources. If a pharmacy won’t verify a prescription or pressures you into bulk orders, walk away. Safe use keeps sildenafil helpful and low-risk—get the facts, then decide.