Comparative Pharmacology
Head-to-head clinical analysis: NORETHINDRONE versus PROVERA.
Peer-Reviewed Evidence
Head-to-head clinical analysis: NORETHINDRONE versus PROVERA.
NORETHINDRONE vs PROVERA
Comparing the clinical profiles, pharmacokinetic behaviors, and safety indices of these two therapeutic agents.
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.
Provera (medroxyprogesterone acetate) is a progestin that binds to progesterone receptors, suppressing gonadotropin secretion, inhibiting endometrial growth, and inducing secretory changes in the endometrium. It also has antigonadotropic effects by reducing LH and FSH release from the pituitary.
5 mg orally once daily for 5 days starting on day 5 of menstrual cycle or 0.35 mg orally once daily for contraception.
Oral: 5-10 mg daily for 5-10 days for secondary amenorrhea; 5-10 mg daily for 12-14 days per cycle in combination with estrogen for endometrial hyperplasia; 400-1000 mg/day IM monthly for endometriosis.
None Documented
None Documented
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).
Terminal elimination half-life is approximately 12-17 hours for medroxyprogesterone acetate (oral). With depot intramuscular injection, the half-life is extended to approximately 50 days due to slow absorption from the injection site.
Renal (30-50% as glucuronide conjugates, 5-10% unchanged), fecal (<10%)
Renal (50-60% as metabolites), biliary/fecal (30-40%). Less than 1% excreted unchanged.
Category D/X
Category C
Progestin
Progestin