Comparative Pharmacology
Head-to-head clinical analysis: MEGACE versus PROVERA.
Peer-Reviewed Evidence
Head-to-head clinical analysis: MEGACE versus PROVERA.
MEGACE vs PROVERA
Comparing the clinical profiles, pharmacokinetic behaviors, and safety indices of these two therapeutic agents.
Megestrol acetate is a synthetic progestin that inhibits pituitary gonadotropin secretion, leading to suppression of ovarian function and reduction of sex hormone levels. It also has antineoplastic effects through interference with estrogen receptor binding and may stimulate appetite via effects on neuropeptide Y and cytokines.
Provera (medroxyprogesterone acetate) is a progestin that binds to progesterone receptors, suppressing gonadotropin secretion, inhibiting endometrial growth, and inducing secretory changes in the endometrium. It also has antigonadotropic effects by reducing LH and FSH release from the pituitary.
Oral: 625 mg (suspension) or 400–800 mg (tablets) once daily.
Oral: 5-10 mg daily for 5-10 days for secondary amenorrhea; 5-10 mg daily for 12-14 days per cycle in combination with estrogen for endometrial hyperplasia; 400-1000 mg/day IM monthly for endometriosis.
None Documented
None Documented
Terminal elimination half-life: 70-95 hours (mean 85 hours) in chronic dosing; shorter in initial doses; clinical context: requires 3-4 weeks to reach steady state.
Terminal elimination half-life is approximately 12-17 hours for medroxyprogesterone acetate (oral). With depot intramuscular injection, the half-life is extended to approximately 50 days due to slow absorption from the injection site.
Primarily renal: ~75% as glucuronide conjugates and unchanged drug; biliary/fecal: ~25% as metabolites.
Renal (50-60% as metabolites), biliary/fecal (30-40%). Less than 1% excreted unchanged.
Category C
Category C
Progestin
Progestin