Tadalafil: uses, dosing, side effects & brands

Adcirca (Tadalafil) is a phosphodiesterase 5 inhibitor used to treat Pulmonary Hypertension, Vasculogenic Impotence.

The FDA classifies tadalafil as a phosphodiesterase 5 inhibitor. PDE5 inhibitors block the enzyme that breaks down cGMP, a signal that relaxes blood vessels. Letting cGMP build up widens vessels and boosts blood flow, which helps erectile dysfunction and eases pressure in the lung arteries. If you are checking whether it is safe to combine with something else, the class is what matters — two drugs from the same class usually should not be stacked.

The elimination half-life of tadalafil is about 17.5 hours — that is how long the body takes to clear half of a dose. This is the elimination half-life of tadalafil itself. Its metabolites are not expected to be pharmacologically active, so none extends the drug's effect. The half-life and drug levels can be higher in older adults (about 25% higher exposure at 65+) and in people with reduced kidney or liver function. Half-life is not the same as how long a drug test can detect the drug, and it varies with age, kidney and liver function.

It depends on the medicine. We check it against the FDA labels rather than guessing: our interaction checker searches each drug's own label for the other and quotes what it says, naming the section it came from. Run tadalafil against whatever else you take — and remember that a label not naming a drug is not the same as that combination being safe.

We track 6 tadalafil-containing products in the U.S.: Adcirca, Alyq, Chewtadzy, Cialis, Tadalafil and Tadliq. They are the same active ingredient; they differ in form, manufacturer, price and FDA recall record.

Across the brands we track, tadalafil is currently marketed as tablet, tablet, chewable and suspension, per the FDA's National Drug Code Directory. Each form is dosed differently — follow the label for the exact product you were prescribed.

Yes. Our catalog lists 2 generic tadalafil products alongside the brand versions. A generic has the same active ingredient and must meet the FDA's bioequivalence standard; it usually costs less. Ask your pharmacist which one your plan covers.

The FDA's Enforcement database lists 3 recall records whose product description mentions tadalafil. The most recent: TADALAFIL USP (Aug 3, 2026). A recall applies to specific lots, not to the drug as a whole — check the record for the affected lot numbers.

Headache is the most common. In the eight primary placebo-controlled ED trials of as-needed Cialis, headache occurred in 15% of men on 20 mg and 11% on both 10 mg and 5 mg, versus 5% on placebo. Indigestion followed at 10% on 20 mg and 8% on 10 mg, versus 1% on placebo. Back pain was 6% at 20 mg versus 3% on placebo, then muscle aches 3-4%, stuffy nose 3%, flushing 3%, and limb pain 3%. Only 3.1% of men on 10 or 20 mg stopped the drug because of side effects, versus 1.4% on placebo. These numbers are for the ED and BPH tablets; Adcirca, the 20 mg tadalafil used for pulmonary arterial hypertension, is a separate product with its own dosing.

Tadalafil has no FDA boxed warning, but it has three hard contraindications. Do not take it with any form of organic nitrate — nitroglycerin, isosorbide, amyl nitrite poppers — whether you use them regularly or only occasionally, because the combination can drop your blood pressure dangerously. Do not take it with a guanylate cyclase stimulator such as riociguat. Do not take it if you have had a serious hypersensitivity reaction to tadalafil as either Cialis or Adcirca; reported reactions include Stevens-Johnson syndrome and exfoliative dermatitis. Because tadalafil stays in your system, if you get chest pain after taking it, go straight to an emergency room and tell them you took tadalafil — at least 48 hours must pass after your last dose before nitroglycerin can even be considered, and then only with close monitoring.

Three situations. An erection lasting more than 4 hours, painful or not, needs emergency medical attention; priapism means a painful erection over 6 hours and, untreated, can permanently damage erectile tissue. Sudden loss of vision in one or both eyes means stop the drug and get medical care — it can signal non-arteritic anterior ischemic optic neuropathy, and your risk is higher if you have had NAION before or have a crowded optic disc. Sudden decrease or loss of hearing, sometimes with ringing in the ears and dizziness, also means stop and seek prompt medical attention. Separately, if you get chest pain during sex, stop, do not continue, and get immediate medical attention.

Back pain or muscle aching from tadalafil typically starts 12 to 24 hours after you take a dose and usually resolves within 48 hours. It is described as a diffuse ache on both sides of the lower back, buttocks, thighs, or lower ribcage, and it tends to get worse when you lie down. In most men it is mild to moderate and goes away without treatment; severe back pain was reported in under 5% of all back pain reports. Back pain occurred in 6% of men on 20 mg versus 3% on placebo. If the pain is severe or does not fade in a couple of days, tell your prescriber rather than repeating the dose.

Strong CYP3A4 inhibitors such as ketoconazole and ritonavir cap your dose: no more than 10 mg once every 72 hours for as-needed use, or 2.5 mg for once-daily use. CYP3A4 inducers such as rifampin cut how much tadalafil you absorb. With alpha-blockers, if you are being treated for ED you must already be stable on the alpha-blocker before starting tadalafil, and you start at the lowest dose; for BPH, tadalafil plus an alpha-blocker is not recommended at all. Substantial alcohol — 5 units or more — plus tadalafil can cause orthostatic drops in blood pressure. With kidney impairment, a creatinine clearance of 30-50 mL/min means starting at 5 mg with a 10 mg maximum every 48 hours, and under 30 mL/min or dialysis means 5 mg maximum every 72 hours. Tadalafil is not recommended in severe liver impairment.