Tadalafil — what it does, how to use it, and what to watch for

Tadalafil is a popular medicine most people know for treating erectile dysfunction (ED). It’s also prescribed for pulmonary arterial hypertension (PAH) and benign prostatic hyperplasia (BPH) in some cases. One thing that stands out: tadalafil can work for up to 36 hours, which is why people call it the “weekend pill.” That long action changes how people take it — either as-needed before sex or once daily.

How tadalafil works and common dosing

Tadalafil relaxes blood vessels by blocking an enzyme called PDE5. For ED you’ll see two common ways to use it: as-needed or daily. As-needed doses usually start at 10 mg taken at least 30 minutes before sex; doctors may adjust this to 5 mg or 20 mg depending on how you respond and side effects. Daily use is lower — typically 2.5–5 mg once every day — so you’re ready any time. For pulmonary arterial hypertension the usual dose is higher and different: 40 mg once daily under a doctor’s care (brand name Adcirca in some regions).

Timing matters. If you take tadalafil before sex, expect it to start in about 30–60 minutes and last up to 36 hours. With daily dosing, steady levels build up so you don’t need to time a pill around sex.

Safety, side effects, and buying tips

Common side effects include headache, flushing, indigestion, back pain, muscle aches, and nasal congestion. Most go away within a day. Serious but rare problems include sudden vision or hearing loss, chest pain, or priapism (a painful erection lasting more than four hours). Seek immediate medical help for those.

Important drug interactions: never combine tadalafil with nitrates (for chest pain). That combo can drop blood pressure dangerously. Be cautious with alpha-blockers for prostate issues; talk to your doctor about timing and doses. Strong CYP3A4 inhibitors like ketoconazole or ritonavir raise tadalafil levels — your prescriber will adjust the dose if needed.

Want to buy tadalafil online? Always use a pharmacy you trust. Look for a valid prescription requirement, clear contact info, and customer reviews. Extremely low prices or no-prescription offers are red flags. In Canada, generic tadalafil is widely available and usually cheaper than branded versions, but quality matters — check credentials or pick pharmacies reviewed on reliable sites.

Simple checklist: get a proper prescription, tell your doctor about other meds and conditions (heart disease, low blood pressure, kidney/liver issues), start at a lower dose if you’re new, and stop and call a doctor if you get severe side effects.

If you’re unsure whether tadalafil is right for you, talk to your healthcare provider. Small changes to dose or timing often make a big difference in safety and satisfaction.