Comparative Pharmacology
Head-to-head clinical analysis: AMEN versus NORETHINDRONE AND ETHINYL ESTRADIOL AND FERROUS FUMARATE.
Peer-Reviewed Evidence
Head-to-head clinical analysis: AMEN versus NORETHINDRONE AND ETHINYL ESTRADIOL AND FERROUS FUMARATE.
AMEN vs NORETHINDRONE AND ETHINYL ESTRADIOL AND FERROUS FUMARATE
Comparing the clinical profiles, pharmacokinetic behaviors, and safety indices of these two therapeutic agents.
Progesterone receptor agonist; induces secretory endometrium, inhibits gonadotropin release, and alters cervical mucus.
Norethindrone is a progestin that suppresses gonadotropin release, inhibiting ovulation. Ethinyl estradiol is an estrogen that provides negative feedback on the hypothalamic-pituitary axis, further suppressing ovulation and altering cervical mucus and endometrial lining. Ferrous fumarate is an iron supplement for replacement of menstrual iron loss.
Medroxyprogesterone acetate (AMEN): 5-10 mg orally once daily for 5-10 days, starting on day 16 or 21 of menstrual cycle; also 150 mg IM every 3 months for contraception.
One tablet (norethindrone 1 mg, ethinyl estradiol 10 mcg, and ferrous fumarate 75 mg) orally once daily at the same time each day for 28 consecutive days, starting on day 1 of menstrual cycle.
None Documented
None Documented
Terminal elimination half-life is approximately 4-6 hours. In severe hepatic impairment, half-life may be prolonged up to 12 hours.
Norethindrone: 5-8 hours (terminal). Ethinyl estradiol: 13-27 hours (terminal). Clinical context: dosing interval is 24 hours based on ethinyl estradiol half-life.
Primarily hepatic metabolism to inactive metabolites, with <1% excreted unchanged in urine. Fecal elimination of metabolites accounts for ~30%.
Norethindrone: ~80% renal (as glucuronide and sulfate conjugates), ~20% fecal. Ethinyl estradiol: ~40% renal, ~60% fecal via enterohepatic recirculation. Ferrous fumarate: iron is absorbed and incorporated; excess excreted in feces as unabsorbed.
Category C
Category D/X
Progestin
Progestin