13 NONCLINICAL TOXICOLOGY
13.1 Carcinogenesis, Mutagenesis, Impairment of Fertility
Long-term animal studies to evaluate the potential for carcinogenesis and animal studies to evaluate the effects on fertility have been performed with each component of diclofenac sodium/misoprostol given alone.
In a 24 month rat carcinogenicity study, misoprostol administered orally at doses up to 2.4 mg/kg/day (14.4 mg/m2/day, 24 times the MRHD of 0.6 mg/m2/day) was not tumorigenic. In a 21 month mouse carcinogenicity study, misoprostol administered orally at doses up to 16 mg/kg/day (48 mg/m2/day), 80 times the MRHD based on body surface area, was not tumorigenic.
In a 24 month rat carcinogenicity study, diclofenac sodium administered orally at up to 2 mg/kg/day (12 mg/m2/day) was not tumorigenic. In a 24 month mouse carcinogenicity study, oral diclofenac sodium at doses up to 0.3 mg/kg/day (0.9 mg/m2/day, 0.006 times the MRHD based on body surface area) in males and 1 mg/kg/day (3 mg/m2/day, 0.02 times the MRHD based on body surface area) in females was not tumorigenic.
Diclofenac sodium and misoprostol combination in 250:1 ratio was not genotoxic in the Ames test, the Chinese hamster ovary cell (CHO/HGPRT) forward mutation test, the rat lymphocyte chromosome aberration test, or the mouse bone marrow micronucleus test.
Impairment of Fertility
The effects of diclofenac sodium and misoprostol on male or female fertility have not been studied in animals; however, there are data with diclofenac sodium and misoprostol given alone. Misoprostol, when administered to male and female breeding rats in an oral dose range of 0.1 to 10 mg/kg/day (0.6 to 60 mg/m2/day, 1 to 100 times the MRHD based on body surface area) produced dose-related pre- and postimplantation losses and a significant decrease in the number of live pups born at the highest dose (60 mg/m2/day, 100 times the MRHD based on body surface area). Diclofenac sodium at oral doses up to 4 mg/kg/day (24 mg/m2/day, 0.16 times the MRHD based on body surface area) was found to have no effect on fertility and reproductive performance of male and female rats.
13.2 Animal Toxicology
A reversible increase in the number of normal surface gastric epithelial cells occurred in the dog, rat, and mouse during long-term toxicology studies with misoprostol. No such increase has been observed in humans administered misoprostol for up to 1 year. An apparent response of the female mouse to misoprostol in long-term studies at 100 to 1000 times the human dose was hyperostosis, mainly of the medulla of sternebrae. Hyperostosis did not occur in long-term studies in the dog and rat and has not been seen in humans treated with misoprostol.