The animal multiples of human exposure calculations are based on body surface area (BSA) comparisons of oral doses administered to animals and an ketoconazole foam, 2% maximum recommended human dose (MRHD) of 8 grams (equivalent to 2.67 mg ketoconazole/kg/day for a 60 kg individual or 98.8 mg ketoconazole/m2/day).
Embryofetal development studies have been conducted in mice, rats and rabbits with orally administered ketoconazole. When orally administered to mice on gestational days 6 through 18 (covering the period of organogenesis), ketoconazole was embryotoxic (25 mg/kg and higher; 0.8 times the MRHD based on BSA comparisons) with a high incidence of resorptions, increased number of stillbirths and delayed parturition. Delays in maturation were also observed. There was no evidence of maternal toxicity or malformations at up to 50 mg/kg (1.5 times the MRHD based on BSA comparisons). No treatment related developmental effects were observed at 10 mg/kg (0.3 times the MRHD based on BSA comparisons).
In the presence of maternal toxicity in rats, orally administered ketoconazole was both embryotoxic (40 mg/kg and higher; 2.4 times the MRHD based on BSA comparisons), including increased resorbed fetuses and stillbirths, and teratogenic (80 mg/kg and higher; 4.8 times the MRHD based on BSA comparisons), including syndactylia, oligodactylia, waved ribs and cleft palate. Additionally, 100 mg/kg (6 times the MRHD based on BSA comparisons) ketoconazole orally administered on a single day during gestation (gestational days 9 through 12) was embryotoxic (increased resorptions). This same oral dose given on gestation day 12, 13, 14 or 15 induced external malformations including cleft palate, micromelia and digital anomalies (brachydactyly, ectrodactyly, syndactyly).
In pregnant rabbits orally administered ketoconazole, evidence of embryotoxicity (increased resorptions) was observed at 10 mg/kg (1.2 times the MRHD based on BSA comparisons) and higher and an increased incidence of skeletal abnormalities was observed at 40 mg/kg (4.8 times the MRHD based on BSA comparisons).