Comparative Pharmacology
Head-to-head clinical analysis: LESSINA 21 versus MICROGESTIN 1 5 30.
Peer-Reviewed Evidence
Head-to-head clinical analysis: LESSINA 21 versus MICROGESTIN 1 5 30.
LESSINA-21 vs MICROGESTIN 1.5/30
Comparing the clinical profiles, pharmacokinetic behaviors, and safety indices of these two therapeutic agents.
Combination oral contraceptive containing ethinyl estradiol and levonorgestrel. Suppresses gonadotropin release (FSH, LH) from pituitary, inhibiting ovulation. Causes cervical mucus thickening and endometrial alterations, impeding sperm penetration and implantation.
Combination oral contraceptive containing norethindrone acetate (progestin) and ethinyl estradiol (estrogen). Suppresses gonadotropin secretion (FSH, LH) via negative feedback on hypothalamic-pituitary axis, preventing ovulation. Also increases cervical mucus viscosity and alters endometrial receptivity.
One tablet (0.1 mg levonorgestrel, 0.02 mg ethinyl estradiol) orally once daily for 21 days, followed by 7 days placebo or no tablets.
One tablet (norethindrone acetate 1.5 mg/ethinyl estradiol 30 mcg) orally once daily at the same time each day for 21 consecutive days, followed by 7 days of placebo tablets.
None Documented
None Documented
17-21 hours (terminal elimination half-life; clinical significance: allows once-daily dosing, but missed doses increase risk of ovulation)
Norethindrone: 8-11 hours; Ethinyl estradiol: 13-19 hours. Steady-state reached within 5-7 days.
Renal (70% as unchanged drug and metabolites), fecal (30% as metabolites)
Renal: ~50-60% (primarily as glucuronide conjugates of ethinyl estradiol and norethindrone); Fecal: ~40-50% (via biliary elimination)
Category C
Category C
Oral Contraceptive
Oral Contraceptive