13 NONCLINICAL TOXICOLOGY
13.1 Carcinogenesis, Mutagenesis, Impairment of Fertility
Tranexamic acid was not carcinogenic in a 2-year study in rats and mice at oral doses up to 3 and 5.3 g/kg/day, which are approximately 12 and 11 times the maximum recommended human dose based on body surface area, respectively.
Tranexamic acid was not genotoxic in the reverse mutation bacterial (Ames) test, and in vitro and in vivo cytogenetic test.
In a fertility and early embryonic development study, tranexamic acid was administered to male rats as 0.3% and 1% of drug in diet (average doses of 222 and 856 mg/kg/day) or to female rats at dose levels of 0.3% and 1.2% of drug in diet. Tranexamic acid had no effect on fertility or reproductive function of male or female rats at dose multiples of 4 or 5 times the maximum recommended human dose based on body surface area, respectively.
13.2 Animal Toxicology and/or Pharmacology
Nonclinical studies have shown a retinal toxicity associated with tranexamic acid. Toxicity is characterized by retinal atrophy commencing with changes to the retinal pigmented epithelium and progressing to retinal detachment in cats. The toxicity appears to be dose related, and changes are partially reversible at lower doses. Effects were observed in dogs at oral doses of 800 mg/kg/day and higher (multiple of 11 times the maximum human dose based on body surface area), and in cats at 250 mg/kg/day for 14 days (multiple of 1.6 times the maximum human dose based on body surface area). Some fully reversible changes in pigmentation were observed in cats at doses of 125 mg/kg/day (multiple of 0.8 times the maximum human dose based on body surface area). Studies suggest that the underlying mechanism may be related to a transient retinal ischemia at high exposures, linked to the known sympathomimetic effect of high plasma exposures of tranexamic acid.