Pharmacology: Pharmacokinetics: Clonazepam is well absorbed following oral administration and peak plasma concentrations have been reported to occur within 4 hours. It is extensively metabolized in the liver, its principal being 7-aminoclonazepam, which has probably has little antiepileptic activity; minor metabolites are the 7-acetamido- and 3-hydroxy derivatives. It is excreted mainly in the urine almost entirely as its metabolites in free or conjugated form. It is about 86% bound to plasma protein and estimations of its plasma half-life range from about 20 to 40 hours, and occasionally more.