The acute toxicity of the drug is low. Overdose causes only harmless side effects such as nausea and vaginal bleeding. The has been found to range between 500 mg/kg in dogs and over 3000 mg/kg in rats. Chronic toxicity has been examined in animals, but nothing but the typical adverse effects of progestogens, and reduction of prostatic weight in rhesus monkeys, have been found. Accidental intake of the drug, including in children, is normally not dangerous. Intake of extremely large doses, or intake by patients with epilepsy or impaired kidney function, can result in central nervous cramping.
