Table 1.
Phosphodiesterase-5 (PDE5) Inhibitors: Pharmacokinetic Summary
| Sildenafil (Viagra) | Vardenafil (Levitra) | Vardenafil ODT (Staxyn) | Tadalafil (Cialis) | Avanafil (Stendra) | |
|---|---|---|---|---|---|
| Bioavailability | 41% (mean) 25%–63% (range) |
15% (mean) | — | — | — |
| Tmax | 1 hour (median) 0.5–2 hours (range) |
1 hour (median) 0.5–2 hours (range) |
1.5 hours (median) 0.75–2.5 hours (range) |
2 hours (median) 0.5–6 hours (range) |
0.5–0.75 hours (range) |
| Vd | 105 L | 208 L | 208 L | 63 L | — |
| Protein binding | 96% | 95% | 95% | 94% | 99% |
| Metabolism | Major: CYP3A4 Minor: CYP2C9 | Major: CYP3A4 Minor: CYP3A5, CYP2C | Major: CYP3A4 Minor: CYP3A5, CYP2C |
CYP3A4 | Major: CYP3A4 Minor: CYP2C |
| Active metabolite (% effect) | Yes (20%) N-desmethylation |
Yes (7%) Desmethylation |
Yes (7%) Desmethylation |
No | Yes (4%) Methylation, glucuronidation |
| Half-life | 4 hours | 4–5 hours | 4–6 hours | 17.5 hours | 5 hours |
| Elimination | 80% feces 13% urine |
91%–95% feces 2%–6% urine |
91%–95% feces 2%–6% urine |
61% feces 36% urine |
62% feces 21% urine |
| Ingestion with high-fat meals | ↓ Cmax 29% ↑ Tmax by 1 hour Avoid |
↓ Cmax 18%–50% May use (per manufacturer) |
↓ Cmax 35% May use (per manufacturer) |
Not affected | ↓ Cmax 24-39% ↑ Tmax by 1.12–1.25 hours May use (per manufacturer) |
| Additional PDE inhibition | PDE1, PDE6 | PDE1, PDE6 | PDE1, PDE6 | PDE11 | — |
Cmax = peak concentration; CYP = cytochrome P450; ODT = oral dissolving tablet; Tmax = time to peak concentration.
Data from prescribing information for sildenafil;8 vardenafil;9 tadalafil;10 avanafil;11 and vardenafil ODT.12