Solifenacin

7 DRUG INTERACTIONS CYP3A4 Inhibitors : Do not exceed the 5 mg dose of Solifenacin succinate tablets with concomitant use of strong CYP3A4 inhibitors. ( 7.1 )

7.1 Strong CYP3A4 Inhibitors Solifenacin is a substrate of CYP3A4. Concomitant use of ketoconazole, a strong CYP3A4 inhibitor, significantly increased the exposure of solifenacin [see Clinical Pharmacology ( 12.3 )] . The dosage of Solifenacin succinate tablets greater than 5 mg once daily is not recommended when concomitantly used with strong CYP3A4 inhibitors [see Dosage and Administration ( 2.4 )] .

8.1 Pregnancy Risk Summary There are no studies with the use of solifenacin succinate in pregnant women to inform a drug-associated risk of major birth defects, miscarriages, or adverse maternal or fetal outcomes. No adverse developmental outcomes were observed in animal reproduction studies with oral administration of solifenacin succinate to pregnant mice during the period of organogenesis at a dose resulting in 1.2 times the systemic exposure at the maximum recommended human dose (MRHD) of 10 mg/day.

However, administration of doses 3.6 times and greater than the MRHD during organogenesis produced maternal toxicity in the pregnant mice and resulted in developmental toxicity and reduced fetal body weights in offspring [see Data ] . In the U.S. general population, the estimated background risk of major birth defects or miscarriage in clinically recognized pregnancies is 2-4% and 15-20%, respectively. Data Animal Data Oral administration of 14 C-solifenacin succinate to pregnant mice resulted in the recovery of radiolabel in the fetus indicating that solifenacin-related product can cross the placental barrier.

In pregnant mice, administration of solifenacin succinate at a dose of 250 mg/kg/day (7.9 times the systemic exposure at the MRHD of 10 mg), resulted in an increased incidence of cleft palate and increased maternal lethality. Administration of solifenacin succinate to pregnant mice during organogenesis at greater than or equal to 3.6 times (100 mg/kg/day and greater) the systemic exposure at the MRHD, resulted in reduced fetal body weights and reduced maternal body weight gain. No embryo-fetal toxicity or teratogenicity was observed in fetuses from pregnant mice treated with solifenacin succinate at a dose of 30 mg/kg/day (1.2 times the systemic exposure at the MRHD).

Administration of solifenacin succinate to pregnant rats and rabbits at a dose of 50 mg/kg/day (< 1 times and 1.8 times the systemic exposure at the MRHD, respectively), resulted in no findings of embryo-fetal toxicity. Oral pre- and post-natal administration of solifenacin succinate at 100 mg/kg/day (3.6 times the systemic exposure at the MRHD) during the period of organogenesis through weaning, resulted in reduced peripartum and postnatal survival, reduced body weight gain by the pups, and delayed physical development (eye opening and vaginal patency).

An increase in the percentage of male offspring was also observed in litters from offspring (F2 generation) exposed to maternal doses of 250 mg/kg/day. There were no effects on natural delivery in mice treated with 1.2 times (30…