Sildenafil: What You Need to Know Right Now

Sildenafil is a medicine people use most often for erectile dysfunction (ED) and sometimes for pulmonary arterial hypertension (PAH). You probably know the brand name Viagra — that’s sildenafil too. This quick guide tells you how it works, common doses, what to watch out for, and simple tips for buying it safely online.

How sildenafil works and common dosing

Sildenafil relaxes blood vessels so blood flows more easily to certain areas. For ED it usually starts working in 30–60 minutes and can last about 4–5 hours. Typical tablet doses are 25 mg, 50 mg, and 100 mg. Most people start at 50 mg taken about an hour before sex, then adjust with a doctor’s help. For PAH, dosing is different and set by a specialist — don’t assume the ED dose applies.

Timing and food matter. A heavy, high-fat meal can delay how fast it works. Alcohol can make side effects worse, so avoid drinking a lot before taking sildenafil.

Safety, interactions, and side effects

There are a few clear no-nos. Never take sildenafil with nitrates (common in angina tablets or sprays) — that combo can dangerously lower blood pressure. Also be cautious if you take alpha-blockers, some blood pressure meds, or certain HIV and antifungal drugs; they can change sildenafil levels. Tell your doctor every medicine you use.

Common side effects are headache, flushing, nasal congestion, upset stomach, and mild vision changes (blue tint or blurred vision). Most are short-lived. Seek urgent care if you get chest pain, severe dizziness, fainting, or an erection lasting more than 4 hours — that needs immediate treatment.

Special groups: if you have severe heart disease, recent stroke, uncontrolled high blood pressure, or severe liver or kidney problems, talk with your doctor first. Older adults may need dose adjustments.

Buying sildenafil online: be smart. Always get a prescription when required. Look for licensed pharmacies that show a physical address and pharmacist contact. Avoid stores that sell without any prescription or that offer suspiciously low prices for name-brand drugs. Check customer reviews and third-party verification (like pharmacy accreditation) when possible.

If you’re choosing between brand-name Viagra and generic sildenafil, generics contain the same active drug and are usually cheaper. Packaging or pill color can differ; what matters is the active ingredient and the pharmacy’s trustworthiness.

Want a safe start? Talk to your doctor about your heart health, current meds, and how often you plan to use sildenafil. That short conversation helps pick the right dose and keeps you out of trouble with interactions or side effects.

If you have questions about specific posts tagged with sildenafil on this site — like buying tips, pharmacy reviews, or drug interactions — check those articles for details tailored to each topic.