Table 2.
Pharmacokinetics of agents for overactive bladder∗
| Parameter | Darifenacin | Flavoxate | Oxybutynin | Solifenacin | Tolterodine | Trospium |
| Oral bioavailability | 15%–25% | N/A | 6% | 90% | 77% | 9.6% |
| Affected by food | No | No | Yes (increased serum concentrations ∼25%) | No | No | Yes (70%–80% reduced absorption with high-fat meal) |
| Time to peak concentration (hours) | 7 | 2 | 1 (IR) 3–6 (ER) 24–48 (patch) | 3–8 | 1–2 (IR) 2–6 (ER) | 4–6 |
| Half-life (hours) | 13–19 | N/A | 1.1–2.3 (IR) 12–16 (ER) | 40–68 | 1.9–3.7 (EM) 9.6 (PM) | 20 |
| Excretion: feces | 40% | N/A | N/A | 23% | 17% | 85% |
| Excretion: renal | 60% | 57% | <0.1% | 3%–6% | 77% | 6% |
| Metabolism | Liver by CYP3A4 and 2D6 to inactive metabolites | Mechanism unknown toactive metabolite | Liver by CYP3A4 to active metabolite (desethyloxy-butynin) | Liver by CYP3A4 to active metabolite (4R-hydroxy-solifenacin) | Liver by CYP2D6 to active metabolite (5-hydroxyethyl-tolterodine) | Liver, not CYPto inactivemetabolites |