Comparative Pharmacology
Head-to-head clinical analysis: LEVONEST versus ORTHO NOVUM 7 7 7 21.
Peer-Reviewed Evidence
Head-to-head clinical analysis: LEVONEST versus ORTHO NOVUM 7 7 7 21.
LEVONEST vs ORTHO-NOVUM 7/7/7-21
Comparing the clinical profiles, pharmacokinetic behaviors, and safety indices of these two therapeutic agents.
Levonorgestrel is a synthetic progestin that inhibits ovulation by suppressing luteinizing hormone (LH) surge, alters cervical mucus to impede sperm penetration, and induces endometrial changes that inhibit implantation.
Combined hormonal contraceptive; primarily suppresses ovulation via inhibition of gonadotropin release (LH and FSH) from the pituitary. Also induces changes in cervical mucus and endometrium.
One tablet (levonorgestrel 1.5 mg) orally as a single dose within 72 hours of unprotected intercourse.
One tablet orally once daily for 21 days, followed by 7 days of no tablets. Each tablet contains norethindrone 0.5 mg/0.75 mg/1 mg and ethinyl estradiol 35 mcg, with biphasic or triphasic dosing per cycle.
None Documented
None Documented
The terminal elimination half-life is approximately 24-30 hours. This relatively long half-life supports once-daily dosing and allows for stable plasma concentrations within 5-7 days of continuous use.
Ethinyl estradiol: 13-27 hours; norethindrone: 8-14 hours; with multiple dosing, steady state after 5-7 days.
Renal excretion of conjugated metabolites accounts for approximately 60-80% of an administered dose; fecal elimination via bile accounts for 20-40%.
Renal: <10% unchanged; biliary/fecal: ~50% as metabolites; extensive enterohepatic recirculation.
Category C
Category C
Oral Contraceptive
Oral Contraceptive