Comparative Pharmacology
Head-to-head clinical analysis: LESSINA 28 versus PIRMELLA 1 35.
Peer-Reviewed Evidence
Head-to-head clinical analysis: LESSINA 28 versus PIRMELLA 1 35.
LESSINA-28 vs PIRMELLA 1/35
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 norethindrone (progestin) and ethinyl estradiol (estrogen) that suppresses gonadotropin secretion via negative feedback on the hypothalamic-pituitary-ovarian axis, inhibiting ovulation. Additionally, causes cervical mucus thickening and endometrial atrophy, reducing sperm penetration and implantation.
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 placebo tablets during the withdrawal bleed.
None Documented
None Documented
Terminal elimination half-life: 18-22 hours; clinically relevant for once-daily dosing.
Terminal half-life 24–30 hours for ethinyl estradiol; 13–18 hours for norethindrone. Steady state reached after 7–10 days.
Renal: 30% as unchanged drug and metabolites; biliary/fecal: 70% as metabolites.
Renal 60–80% as metabolites (glucuronide conjugates), biliary/fecal 10–20%.
Category C
Category C
Oral Contraceptive
Oral Contraceptive