Answer:
Etretinate, a medication that was used in the treatment of severe psoriasis, has a long elimination half-life. After discontinuation of etretinate, its metabolite acitretin can still be detected in the sera of patients for an extended period. The elimination half-life of acitretin is approximately 2 to 3 days, but it undergoes further metabolism to its inactive metabolite, etretinic acid, which has a much longer half-life.
Etretinate and its metabolites can be detected in the body for several months after the drug is discontinued. The long persistence of these substances in the body is a consideration in cases where individuals, particularly women of childbearing age, discontinue etretinate and are advised to wait for a certain period before attempting pregnancy due to the potential teratogenic effects of the drug.
