Think sildenafil is just a brand name you’ve heard in jokes? It’s the active drug behind many treatments for erectile dysfunction (ED) and pulmonary arterial hypertension. Knowing how it works, when to take it, and what to watch for makes a big difference in safety and results.
Sildenafil relaxes blood vessels by blocking an enzyme called PDE5. For ED this helps blood flow into the penis when you're sexually aroused. For pulmonary hypertension it lowers pressure in lung arteries so the heart pumps easier. The effect usually starts within 30–60 minutes and can last 4–6 hours for ED doses.
Common ED doses are 25 mg, 50 mg, or 100 mg taken as needed about an hour before sex. Start low—many people begin at 50 mg or 25 mg if they’re older or on other meds. For pulmonary hypertension, doses and schedules differ and your doctor will prescribe them. Avoid alcohol and heavy meals with lots of fat right before taking sildenafil; they can slow how fast it works.
If you miss a dose for daily/PAH regimens, don’t double up. Store tablets in a cool, dry place. Don't share prescription medication with others—dosage and risks depend on your heart, blood pressure, and other meds.
Mild side effects are common: headache, flushing, nasal congestion, and indigestion. Serious problems are rare but need immediate attention. Never take sildenafil with nitrates (often prescribed for chest pain)—the combo can cause a dangerous drop in blood pressure. Also be cautious with alpha-blockers, and strong CYP3A4 inhibitors like ritonavir, ketoconazole, or some grapefruit products because they raise sildenafil levels.
Seek urgent care if you get sudden vision loss, sudden hearing loss, chest pain, fainting, or an erection lasting more than 4 hours (priapism). These are rare but serious.
If you have heart disease, low blood pressure, uncontrolled high blood pressure, recent stroke, or severe liver problems, talk with your doctor before using sildenafil. Your provider will weigh benefits vs risks and may choose a different treatment.
Want alternatives? Tadalafil (Cialis) lasts much longer—up to 36 hours—and may fit different lifestyles. Vardenafil is another short-acting option. Each drug has different timing and side effect patterns, so discuss choices with your clinician.
Buying online? Use only licensed pharmacies that require a prescription, show a physical address, and offer pharmacist contact. Avoid sites that sell sildenafil without asking for a doctor’s exam. Cheap pills from unknown sources risk counterfeit ingredients, wrong doses, or dangerous contaminants.
Good questions to ask your prescriber: Is this dose right for my age and health? How will this interact with my current meds? When should I stop and call you? Clear answers keep you safer and more confident using sildenafil.
Learn all about Caverta—what it is, how it works, its effects, tips for safe use, and facts every user should know before starting this ED medication.
