Some pharmacokinetic characteristics of the “major” PDE inhibitors
| Sildenafil | Vardenafil | Tadalafil | |
|---|---|---|---|
| Oral bioavailability, % | 38–41 | 15 (8–25) | N.A. |
| Tmax, h | 1 (0.5–2) | 0.7 (0.25–3) | 2 (05–6) |
| Cmax, μg/l (fasting) | 560 (100 mg) | 20.9 (20 mg) | 378 (20 mg) |
| Cmax, food effect | 29% reduction | 18% reduction | No effect |
| t1/2, h | 3–5 | 4–5 | 17.5 |
| Cytochrome P450 isoenzyme | 3A4, 2C9 | 3A4 | 3A4 |
| Active metabolite | Yes | Yes | None |
N.A., not available.
Modified from Gupta M, Kovar A, and Meibohm B (2005) The clinical pharmacokinetics of phosphodiesterase-5 inhibitors for erectile dysfunction. J Clin Pharmacol 45:987–1003. Copyright © 2005 American College of Clinical Pharmacology, Inc. Used with permission.