Comparative Pharmacology
Head-to-head clinical analysis: LEVONORGESTREL versus NORETHINDRONE ACETATE AND ETHINYL ESTRADIOL AND FERROUS FUMARATE.
Peer-Reviewed Evidence
Head-to-head clinical analysis: LEVONORGESTREL versus NORETHINDRONE ACETATE AND ETHINYL ESTRADIOL AND FERROUS FUMARATE.
LEVONORGESTREL vs NORETHINDRONE ACETATE AND ETHINYL ESTRADIOL AND FERROUS FUMARATE
Comparing the clinical profiles, pharmacokinetic behaviors, and safety indices of these two therapeutic agents.
Synthetic progestin that suppresses gonadotropin release (GnRH, LH, FSH) via negative feedback on the hypothalamic-pituitary-ovarian axis; inhibits ovulation, thickens cervical mucus, and alters endometrial lining.
Norethindrone acetate is a progestin that suppresses gonadotropin release, inhibiting ovulation and altering cervical mucus and endometrium. Ethinyl estradiol is an estrogen that provides cycle control and contributes to contraceptive efficacy. Ferrous fumarate provides iron supplementation.
For emergency contraception: 1.5 mg orally as a single dose or 0.75 mg orally 12 hours apart. For hormonal contraception: 0.03 mg to 0.05 mg orally once daily in combined oral contraceptives; for progestin-only oral contraceptive (mini-pill): 0.03 mg orally once daily. For intrauterine system (IUD): 52 mg intrauterine device inserted for up to 5 years.
One tablet (1 mg norethindrone acetate, 20 mcg ethinyl estradiol, and 75 mg ferrous fumarate) orally once daily for 28 days, without interruption. Take the first tablet on the first day of menstrual bleeding.
None Documented
None Documented
Clinical Note
moderateLevonorgestrel + Sulfisoxazole
"The metabolism of Sulfisoxazole can be decreased when combined with Levonorgestrel."
Clinical Note
moderateLevonorgestrel + Erythromycin
"The metabolism of Erythromycin can be decreased when combined with Levonorgestrel."
Clinical Note
moderateLevonorgestrel + Cyclosporine
"The metabolism of Cyclosporine can be decreased when combined with Levonorgestrel."
Clinical Note
moderateLevonorgestrel + Fluconazole
Terminal half-life: 24-30 hours (range 11-45 hours). This prolonged half-life supports once-daily or extended-cycle dosing in contraceptive formulations.
Norethindrone: 8-11 hours (terminal). Ethinyl estradiol: 10-20 hours (terminal). Clinical context: Steady-state achieved after 5-7 days; half-life supports once-daily dosing.
Renal: 45-60% (metabolites), Fecal: 32-45% (unchanged and metabolites). Biliary excretion contributes to fecal elimination.
Norethindrone acetate and ethinyl estradiol are primarily excreted in urine (40-60% as metabolites) and feces (20-40% as metabolites). Ferrous fumarate is absorbed and iron is utilized; unabsorbed iron is excreted in feces.
Category C
Category D/X
Progestin
Progestin
"The metabolism of Fluconazole can be decreased when combined with Levonorgestrel."