Tadalafil: What it does, how to use it, and how to stay safe

Tadalafil (brand name Cialis) is one of the most common drugs for erectile dysfunction (ED). It also treats benign prostatic hyperplasia (BPH) and pulmonary arterial hypertension (PAH) under different brand names and doses. If you're curious about how it works, how long it lasts, or whether it’s safe for you, this page gives practical, no-nonsense guidance.

How tadalafil works and typical doses

Tadalafil relaxes blood vessels by blocking an enzyme called PDE5. That helps increase blood flow to the penis during sexual arousal. For ED taken as needed, common starting doses are 10 mg about 30–60 minutes before sex; you can adjust to 5 mg or 20 mg based on effect and side effects. For daily use (helpful if you have frequent sexual activity), typical doses are 2.5–5 mg once daily. For PAH, tadalafil is usually given at a higher daily dose (often 40 mg) under specialist supervision. Always follow a prescriber's instructions — doses vary by condition and health status.

Safety, side effects, and important drug interactions

Common side effects are headache, flushing, nasal congestion, indigestion, back pain and muscle aches. These often fade after a few hours or days. Seek urgent care if you get sudden vision loss, sudden hearing loss, or an erection lasting longer than 4 hours (priapism) — those are medical emergencies.

Don’t mix tadalafil with nitrates (like nitroglycerin) — the combo can cause a dangerous drop in blood pressure. Be careful if you take alpha-blockers for prostate or blood pressure; combine only under doctor guidance and often with dose spacing. Strong CYP3A4 inhibitors (ketoconazole, ritonavir) raise tadalafil levels — your prescriber may lower the dose. Moderate alcohol can worsen dizziness and low blood pressure; avoid heavy drinking when using tadalafil.

Kidney or liver problems change how long tadalafil stays in your body. Older adults may need lower doses. If you have heart disease, recent stroke, or unstable angina, check with your doctor before using any ED medicine.

Thinking of buying tadalafil online? Use only licensed pharmacies that require a prescription and show clear contact info and accreditation. Watch for drastically low prices, no-prescription offers, or websites that hide company details — those are red flags. If you want help comparing options, our site has pharmacy safety guides and articles on buying meds online safely.

Storage is simple: keep tablets in a cool, dry place away from children. Never share prescription medications. If tadalafil doesn't work as expected or causes troubling side effects, talk to your clinician — there are other ED options, dose changes, or tests that can help.

Questions about interactions with medicines you already take? Run them by a pharmacist or your prescriber — a short chat can prevent serious problems. If you want deeper reads, check our related articles on ED alternatives, safe online pharmacies, and drug interaction tips on GenericDay.