Teratogenesis in cats associated with griseofulvin therapy.

Multiple congenital malformations occurred in kittens of three cats treated orally at weekly intervals with 500-1000 mg of the antifungal drug griseofulin. Malformations of the brain included exencephaly, malformed prosencephalon, caudal displacement, and hydrocephalus. Skeletal malformations included cranium bifidium, spina bifida (C1 through C4, and sacral), abnormal atlantooccipital articulation, cleft palate, absence of maxillae, and lack of tail vertebrae. Cyclopia and anophthalmia with absence of optic nerves and rudimentary optic tracts were also observed. Atresia ani, atresia coli, lack of atrioventricular valves in the heart, and absence of external nares and soft palate were other abnormalities present.