Comparative Pharmacology
Head-to-head clinical analysis: LESSINA 28 versus LYBREL.
Peer-Reviewed Evidence
Head-to-head clinical analysis: LESSINA 28 versus LYBREL.
LESSINA-28 vs LYBREL
Comparing the clinical profiles, pharmacokinetic behaviors, and safety indices of these two therapeutic agents.
Combination of a progestin (levonorgestrel) and an estrogen (ethinyl estradiol). Inhibits ovulation by suppressing gonadotropin release; increases cervical mucus viscosity to impede sperm penetration, and induces endometrial changes that reduce implantation likelihood.
Combination of levonorgestrel and ethinyl estradiol: suppression of gonadotropins (FSH and LH) via negative feedback, inhibiting ovulation; thickening of cervical mucus to impede sperm penetration; alteration of endometrium to reduce implantation likelihood.
One tablet (0.1 mg levonorgestrel and 0.02 mg ethinyl estradiol) orally once daily for 28 days, starting on the first day of menstrual cycle.
One tablet (levonorgestrel 0.1 mg/ethinyl estradiol 0.02 mg) orally once daily for 21 days, followed by 7 placebo tablets for 28-day cycle.
None Documented
None Documented
Terminal elimination half-life: 18-22 hours; clinically relevant for once-daily dosing.
Terminal elimination half-life: 27 ± 8 hours; requires ~5 days to reach steady-state; clinical significance: missed doses lead to rapid loss of contraceptive efficacy.
Renal: 30% as unchanged drug and metabolites; biliary/fecal: 70% as metabolites.
Renal: 50-60% as metabolites, ~20% as parent drug; fecal: 30-40%; biliary: 10-20%.
Category C
Category C
Oral Contraceptive
Oral Contraceptive