Comparative Pharmacology
Head-to-head clinical analysis: MEGACE versus NORETHINDRONE.
Peer-Reviewed Evidence
Head-to-head clinical analysis: MEGACE versus NORETHINDRONE.
MEGACE vs NORETHINDRONE
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.
Norethindrone is a synthetic progestin that binds to progesterone receptors, suppressing gonadotropin (LH and FSH) release from the pituitary, inhibiting ovulation, and inducing secretory changes in the endometrium. It also has weak androgenic and estrogenic activity.
Oral: 625 mg (suspension) or 400–800 mg (tablets) once daily.
5 mg orally once daily for 5 days starting on day 5 of menstrual cycle or 0.35 mg orally once daily for contraception.
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: 5-14 hours (mean 8-10 hours); clinical context: requires once-daily dosing for steady state after ~2 days (5 half-lives).
Primarily renal: ~75% as glucuronide conjugates and unchanged drug; biliary/fecal: ~25% as metabolites.
Renal (30-50% as glucuronide conjugates, 5-10% unchanged), fecal (<10%)
Category C
Category D/X
Progestin
Progestin