Comparative Pharmacology
Head-to-head clinical analysis: LESSINA 28 versus NORTREL 1 35 21.
Peer-Reviewed Evidence
Head-to-head clinical analysis: LESSINA 28 versus NORTREL 1 35 21.
LESSINA-28 vs NORTREL 1/35-21
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 ethinyl estradiol (estrogen) and norethindrone (progestin) suppresses gonadotropin (FSH and LH) release from the pituitary, inhibiting ovulation, altering cervical mucus to impede sperm penetration, and inducing endometrial changes that 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 orally once daily for 21 days, followed by 7 days off, then repeat.
None Documented
None Documented
Terminal elimination half-life: 18-22 hours; clinically relevant for once-daily dosing.
Norethindrone: 5-14 hours; Ethinyl estradiol: 17-24 hours. Steady-state achieved after 10 days.
Renal: 30% as unchanged drug and metabolites; biliary/fecal: 70% as metabolites.
Renal 50-60% as metabolites, fecal 40-50% as conjugates, <1% unchanged
Category C
Category C
Oral Contraceptive
Oral Contraceptive