Prednisone reduces ketoconazole-induced skeletal defects in rat fetuses

Ketoconazole (KT) is a broad-spectrum antifungal agent whose pharmacological activity is based on the capability to interfere with steroid biosynthesis through an interaction with fungal cytochrome P-450 enzymes and thereby avoiding the formation of fungal walls. As the inhibition of fungal cytochrome P-450 by KT is not specific, the mammalian cytochrome P-450 species, which play an important role in the biosynthesis of steroidogenesis, are also affected. The reproductive and developmental toxicity of KT have been assessed. This antimycotic agent has been reported as embryotoxic and teratogenic when administered in high doses (80 mg/kg) to pregnant rats. The mechanisms by which KT exert teratogenic effects remains to be elucidated. When considering the potential inhibitory effect of KT on mammalian steroid biosynthesis as a possible responsible for the skeletal anomalies induced by this drug, this study aimed at determining whether steroid maternal supplementation may prevent the skeletal anomalies induced by KT. To test this hypothesis, maternal supplementation with prednisone (PRED) (0.1, 0.2 or 0.4 mg/kg) and 80 mg/kg of KT were administered to pregnant Wistar rats (n = 10) during organogenesis period. On gestational day 21, the dams were euthanized and examined for standard parameters of reproductive outcome. In summary, the results showed that PRED supplementation therapy may cause reductions in the incidence of KT-induced cranial and appendicular skeletal anomalies as well as cleft palate in the rat, being these results more consistent with 0.4 mg/kg of this drug. These results suggest an important role for glucocorticoids in KT-induced teratogenesis.