Comparative Pharmacology
Head-to-head clinical analysis: MICROGESTIN 1 20 versus NORLESTRIN 28 1 50.
Peer-Reviewed Evidence
Head-to-head clinical analysis: MICROGESTIN 1 20 versus NORLESTRIN 28 1 50.
MICROGESTIN 1/20 vs NORLESTRIN 28 1/50
Comparing the clinical profiles, pharmacokinetic behaviors, and safety indices of these two therapeutic agents.
Combination oral contraceptive containing estrogen (ethinyl estradiol) and progestin (norethindrone acetate). Inhibits gonadotropin secretion (FSH, LH) via negative feedback, preventing ovulation. Also causes cervical mucus thickening and endometrial thinning.
Combination estrogen-progestin oral contraceptive; suppresses gonadotropin release via negative feedback on pituitary, inhibits ovulation, thickens cervical mucus, alters endometrial receptivity.
One tablet (norethindrone acetate 1 mg / ethinyl estradiol 20 mcg) orally once daily for 21 consecutive days, followed by 7 days of placebo or no tablets.
One tablet orally once daily, each containing norethindrone 1 mg and ethinyl estradiol 50 mcg.
None Documented
None Documented
Norethindrone: 5.2-12.8 hours (mean ~8 hours); Ethinyl estradiol: 7-20 hours (mean ~13 hours); hepatic impairment prolongs.
Norethindrone: 8 hours; ethinyl estradiol: 12-15 hours; steady state achieved within 5-10 days.
Renal: 40% as metabolites, 20% as glucuronide and sulfate conjugates; Fecal: 35%; Biliary: <5%.
Norethindrone: 40% renal, 60% fecal; ethinyl estradiol: 40% renal, 60% fecal.
Category C
Category C
Oral Contraceptive
Oral Contraceptive