Comparative Pharmacology
Head-to-head clinical analysis: MEGACE ES versus NORGESTIMATE ETHINYL ESTRADIOL.
Peer-Reviewed Evidence
Head-to-head clinical analysis: MEGACE ES versus NORGESTIMATE ETHINYL ESTRADIOL.
MEGACE ES vs NORGESTIMATE; ETHINYL ESTRADIOL
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.
Combination oral contraceptive containing norgestimate (a progestin) and ethinyl estradiol (an estrogen). The primary mechanism is suppression of gonadotropins (FSH and LH) via negative feedback on the hypothalamic-pituitary-ovarian axis, preventing ovulation. Additional effects include thickening cervical mucus (inhibiting sperm penetration) and altering endometrial receptivity.
625 mg orally once daily (MEGACE ES suspension contains 625 mg/5 mL; shake well before use). For appetite stimulation in cachexia.
Oral, one tablet daily at the same time for 21 days, followed by 7 placebo tablets.
None Documented
None Documented
Approximately 34 hours in plasma; steady-state achieved after 2-3 weeks of daily dosing.
Norgestimate: terminal half-life of norelgestromin (active metabolite) is 27.6 ± 7.8 hours; ethinyl estradiol: terminal half-life is 17.5 ± 6.3 hours. Steady state achieved within 14 days.
Primarily renal (≤1% unchanged) and biliary; extensive metabolism to inactive glucuronide conjugates excreted in feces.
Norgestimate metabolites are primarily excreted via urine (60-80%) and feces (35-49%) as glucuronide and sulfate conjugates; ethinyl estradiol is excreted in urine (40%) and feces (60%) as conjugates.
Category C
Category D/X
Progestin
Progestin + Estrogen