In animal studies mice, rats and dogs were involved. They were treated with tadalafil to estimate the toxicology of the drug.
Animal studies demonstrated vascular inflammation in animals. In mice and rats lymphoid necrosis and hemorrhage were seen in the spleen. In dogs the increased risk of disseminated arthritis was seen in 6 month studies. In a 12- month dog study, two dogs got marked decreases in white blood cells (neutrophils) and moderate decreases in platelets with inflammatory signs. Still these abnormalities disappeared after 2 weeks of removal of the drug.
Reproductions studies have shown no evidence of impaired fertility in mice and rats treated with tadalafil.
Teratogenicity, embryotoxicity and fetotoxicity have demonstrated no signs also: tadalafil was given to pregnant rats and mice.
Tadalafil and its metabolites were observed to cross the placenta, resulting in fetal exposure in rats. Tadalafil and its metabolites were found in the milk of lactating rats in higher concentrations than in plasma.