Comparative Pharmacology
Head-to-head clinical analysis: MEGACE ES versus NORETHINDRONE AND ETHINYL ESTRADIOL 7 14.
Peer-Reviewed Evidence
Head-to-head clinical analysis: MEGACE ES versus NORETHINDRONE AND ETHINYL ESTRADIOL 7 14.
MEGACE ES vs NORETHINDRONE AND ETHINYL ESTRADIOL (7/14)
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 and testicular hormone production. It also has antineoplastic effects possibly through local action on hormone-sensitive tissues and stimulates appetite via modulation of neuropeptide Y and other appetite-regulating factors.
Norethindrone is a progestin that suppresses gonadotropin release, preventing ovulation. Ethinyl estradiol is an estrogen that provides negative feedback on the hypothalamic-pituitary axis, further inhibiting ovulation. The combination also alters cervical mucus and endometrial lining to impede fertilization and implantation.
625 mg orally once daily (MEGACE ES suspension contains 625 mg/5 mL; shake well before use). For appetite stimulation in cachexia.
One tablet (norethindrone 0.5 mg/ethinyl estradiol 35 mcg) orally once daily for 21 days (7 active tablets of norethindrone 0.5 mg/ethinyl estradiol 35 mcg followed by 14 active tablets of norethindrone 1 mg/ethinyl estradiol 35 mcg). Start on day 1 of menstrual cycle.
None Documented
None Documented
Approximately 34 hours in plasma; steady-state achieved after 2-3 weeks of daily dosing.
Norethindrone: 8-11 hours; Ethinyl estradiol: 17-27 hours. Achieves steady state within 5-10 days, permitting once-daily dosing.
Primarily renal (≤1% unchanged) and biliary; extensive metabolism to inactive glucuronide conjugates excreted in feces.
Norethindrone: ~50% renal, ~50% fecal; Ethinyl estradiol: ~50% renal, ~50% fecal, with enterohepatic circulation.
Category C
Category D/X
Progestin
Progestin