Comparative Pharmacology
Head-to-head clinical analysis: LEVONEST versus ORTHO NOVUM 7 14 21.
Peer-Reviewed Evidence
Head-to-head clinical analysis: LEVONEST versus ORTHO NOVUM 7 14 21.
LEVONEST vs ORTHO-NOVUM 7/14-21
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.
Combination estrogen-progestin contraceptive: suppresses gonadotropin release, inhibits ovulation, thickens cervical mucus, alters endometrial receptivity.
One tablet (levonorgestrel 1.5 mg) orally as a single dose within 72 hours of unprotected intercourse.
One tablet containing 0.5 mg norethindrone/0.035 mg ethinyl estradiol (white tablets) on days 1-14, then one tablet containing 1 mg norethindrone/0.035 mg ethinyl estradiol (peach tablets) on days 15-21, then no tablets for 7 days; repeated cycles.
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.
Norethindrone: 10-12 hours (terminal), ethinyl estradiol: 13-27 hours (terminal); clinical context: steady state achieved within 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: ~40% as glucuronide and sulfate conjugates; Fecal: ~20%; Biliary: minor
Category C
Category C
Oral Contraceptive
Oral Contraceptive