Comparative Pharmacology
Head-to-head clinical analysis: NORETHINDRONE ACETATE versus NORGESTIMATE ETHINYL ESTRADIOL.
Peer-Reviewed Evidence
Head-to-head clinical analysis: NORETHINDRONE ACETATE versus NORGESTIMATE ETHINYL ESTRADIOL.
NORETHINDRONE ACETATE vs NORGESTIMATE; ETHINYL ESTRADIOL
Comparing the clinical profiles, pharmacokinetic behaviors, and safety indices of these two therapeutic agents.
Progestin that suppresses gonadotropin secretion, inhibits ovulation, and induces endometrial thinning. Also binds to progesterone receptors, exerting antiestrogenic effects.
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.
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.
Oral, one tablet daily at the same time for 21 days, followed by 7 placebo tablets.
None Documented
None Documented
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.
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.
Renal (39-61% as metabolites), biliary/fecal (35-49% as metabolites). Less than 1% excreted unchanged.
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 D/X
Category D/X
Progestin
Progestin + Estrogen