Comparative Pharmacology
Head-to-head clinical analysis: NORDETTE 28 versus NORINYL 1 50 21 DAY.
Peer-Reviewed Evidence
Head-to-head clinical analysis: NORDETTE 28 versus NORINYL 1 50 21 DAY.
NORDETTE-28 vs NORINYL 1+50 21-DAY
Comparing the clinical profiles, pharmacokinetic behaviors, and safety indices of these two therapeutic agents.
Combined estrogen-progestin oral contraceptive. Suppresses gonadotropin (FSH, LH) release from pituitary, inhibiting ovulation. Increases cervical mucus viscosity and alters endometrial lining.
Norinyl 1+50 21-Day contains norethindrone (a progestin) and mestranol (an estrogen). Mestranol is converted to ethinyl estradiol, which provides negative feedback on gonadotropin release, inhibiting ovulation. Norethindrone suppresses gonadotropins and alters cervical mucus and endometrial lining to prevent implantation.
One tablet orally once daily for 28 consecutive days.
One tablet (1 mg norethindrone + 0.05 mg mestranol) orally once daily for 21 days, followed by 7 placebo tablets. Start on day 1 of menstrual cycle or first Sunday after onset.
None Documented
None Documented
Ethinyl estradiol: 13-27 hours (mean 17 hours); Levonorgestrel: 11-45 hours (mean 24 hours); clinical context: steady-state reached after 5-7 days.
Norethindrone: 5-8 hours; Ethinyl estradiol: 7-15 hours; steady-state reached within 5-7 days
Renal: ~50% as metabolites, ~20% unchanged; Fecal: ~30% as metabolites; Biliary: minimal.
Renal (40% as metabolites), fecal (50% as metabolites), <1% unchanged
Category C
Category C
Combined Oral Contraceptive
Combined Oral Contraceptive