Adults

For daily use in ED or BPH: 5 mg once daily, taken at approximately the same time each day, regardless of timing of sexual activity. For ED as needed: 10 mg or 20 mg as a single dose, at least 30 minutes prior to anticipated sexual activity. (Note: 5mg is for daily use).

Elderly

No dose adjustment is generally required based on age alone, but caution is advised in elderly patients due to potential comorbidities.

Renal_impairment

For creatinine clearance (CrCl) 30-50 mL/min: Initial dose 5 mg once daily, maximum 10 mg every 48 hours. For CrCl <30 mL/min or on hemodialysis: Maximum 5 mg every 72 hours (for ED/BPH daily use). For BPH, generally 5 mg once daily.

Onset

Typically 30-60 minutes.

Excretion

Excreted predominantly in the feces (approximately 61% of the dose) and to a lesser extent in the urine (approximately 36% of the dose).

Half life

Approximately 17.5 hours.

Absorption

Rapidly absorbed after oral administration. Peak plasma concentration (Cmax) is achieved within 30 minutes to 6 hours (median 2 hours).

Metabolism

Primarily metabolized by the cytochrome P450 (CYP) 3A4 isoenzyme in the liver.

Alcohol

Excessive alcohol consumption may increase the risk of orthostatic hypotension.

Nitrates

Potentiation of hypotensive effects, potentially life-threatening. Concomitant use is contraindicated.

Alpha-blockers

May potentiate hypotensive effects, particularly with concurrent use. Dose adjustment or staggered administration may be necessary.

Antihypertensives

May cause additive blood pressure lowering effects.

CYP3A4 Inducers (e.g., Rifampin)

May decrease Tadalafil exposure (AUC) and Cmax, potentially reducing efficacy. Dose adjustment may be required.

CYP3A4 Inhibitors (e.g., Ketoconazole, Ritonavir)

May increase Tadalafil exposure (AUC) and Cmax, leading to increased risk of side effects. Dose adjustment may be required.