Comparative Pharmacology
Head-to-head clinical analysis: MEGACE versus NORETHINDRONE ACETATE.
Peer-Reviewed Evidence
Head-to-head clinical analysis: MEGACE versus NORETHINDRONE ACETATE.
MEGACE vs NORETHINDRONE ACETATE
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.
Progestin that suppresses gonadotropin secretion, inhibits ovulation, and induces endometrial thinning. Also binds to progesterone receptors, exerting antiestrogenic effects.
Oral: 625 mg (suspension) or 400–800 mg (tablets) once daily.
Oral, 5 mg once daily for 14 days per cycle, beginning on day 1 of menstrual cycle; for endometriosis, 5 mg daily for 14 days then 10 mg daily for 14 days, then 15 mg daily, or as tolerated up to 15 mg daily continuous.
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 5-8 hours (mean 7.5 hours). Clinically, steady-state is achieved within 2-3 days of daily dosing.
Primarily renal: ~75% as glucuronide conjugates and unchanged drug; biliary/fecal: ~25% as metabolites.
Renal (39-61% as metabolites), biliary/fecal (35-49% as metabolites). Less than 1% excreted unchanged.
Category C
Category D/X
Progestin
Progestin