Mechanism of action:
Megestrol Acetate is a synthetic progestational anticancer drug. It may work by interfering with the hormone balance in the body, which may stop the cancer growing. It may also act directly on cancer cells so that they can't grow. Moreover, Megestrol Acetate causes weight gain by increasing the fat and body cell mass and this weight gain is associated with increased appetite. Therefore this drug is used as an appetizer for the cancer patients suffering from anorexia, significant weight loss or cachexia.
Absorption: tmax=2-3 hrs.
Distribution: Plasma concentrations (90-110 ng/mL) occur after the administration of one 160 mg tablet or four 40 mg tablets given over 24 hours.
Metabolism: Mainly hepatic metabolism. The metabolites are three glucuronide conjugates with hydroxylation occurring at either the 2-alpha, or the 6 methyl position or at both positions.
Elimination: 66% in Urine and 20% in feces.
Half-life: t1/2=33-38 hrs.