Sildenafil Citrate: What It Does and What You Need to Know

Sildenafil citrate is the active ingredient in Viagra and a common generic for treating erectile dysfunction (ED). It also treats pulmonary arterial hypertension under different brand names. Sounds simple, right? But this drug can help a lot and hurt quickly if used wrong. Read the key facts so you use it safely and get results when you need them.

How sildenafil works and common dosing

Sildenafil blocks an enzyme called PDE5, which helps increase blood flow to the penis when you’re sexually aroused. For ED, doctors usually start with 50 mg about 30–60 minutes before sex. Depending on how you respond, the dose can be lowered to 25 mg or raised to 100 mg. Take it on an empty stomach for faster effect; a heavy meal can slow it down. For pulmonary hypertension, dosing and schedules differ, so follow your specialist’s instructions.

Don’t expect it to create spontaneous erections without arousal. Think of it as a tool that helps your body respond better when it’s already turned on.

Side effects, warnings, and dangerous interactions

Common side effects include headache, flushing, nasal congestion, upset stomach, and mild vision changes (blue tint or increased brightness). If you get severe chest pain, sudden vision loss, or an erection lasting more than 4 hours (priapism), seek emergency care right away.

Big warning: never take sildenafil with nitrates (like nitroglycerin). Mixing them can cause a dangerous drop in blood pressure. Use caution with alpha-blockers, some blood pressure meds, and certain HIV or antifungal drugs — they can raise sildenafil levels. Grapefruit juice can also increase levels, so avoid it around dosing time.

If you have heart disease, uncontrolled high or low blood pressure, severe liver or kidney problems, or a history of stroke, talk with your doctor before using sildenafil. Your doctor will weigh the benefits against risks and may suggest tests or a lower dose.

Buying sildenafil online — smart, safe tips

Online pharmacies can offer lower prices for generic sildenafil. Before you buy, make sure the site requires a prescription and shows clear contact details. Avoid sites selling pills without labels or unbelievably cheap imports. Check reviews and look for pharmacy accreditation if available. Remember cross-border purchases can run into customs and regulatory issues — check local rules first.

Compare prices, but don’t sacrifice safety for a few dollars. If cost is a problem, ask your doctor about generics, coupon programs, or patient assistance programs. Finally, keep a list of your current meds and show it to your prescriber so interactions are avoided.

Sildenafil citrate is effective when used correctly. Stick to prescribed doses, watch for interactions, and buy from reputable sources. If anything feels off while taking it, contact your healthcare provider promptly.