Comparative Pharmacology
Head-to-head clinical analysis: ORTHO NOVUM 1 50 21 versus ORTHO TRI CYCLEN LO.
Peer-Reviewed Evidence
Head-to-head clinical analysis: ORTHO NOVUM 1 50 21 versus ORTHO TRI CYCLEN LO.
ORTHO-NOVUM 1/50 21 vs ORTHO TRI-CYCLEN LO
Comparing the clinical profiles, pharmacokinetic behaviors, and safety indices of these two therapeutic agents.
Combination oral contraceptive consisting of mestranol (estrogen) and norethindrone (progestin). Mestranol is converted to ethinyl estradiol, which suppresses gonadotropin release (FSH, LH) from the pituitary, inhibiting ovulation. Norethindrone induces changes in cervical mucus (increasing viscosity) and endometrial lining, creating a hostile environment for sperm implantation.
Combination estrogen (ethinyl estradiol) and progestin (norgestimate) oral contraceptive. Suppresses gonadotropin release, inhibiting ovulation; increases cervical mucus viscosity, impeding sperm penetration; alters endometrial lining, reducing implantation likelihood.
One tablet orally once daily for 21 days, followed by 7 tablet-free days. Each tablet contains 1 mg norethindrone and 50 mcg mestranol.
One tablet daily orally for 21 days, followed by 7 placebo tablets. Each active tablet contains 0.025 mg ethinyl estradiol and 0.18 mg norelgestromin (days 1-7), 0.215 mg norelgestromin (days 8-14), 0.25 mg norelgestromin (days 15-21).
None Documented
None Documented
Norethindrone: biphasic terminal half-life 7-9 hours for parent compound, 8-11 hours for metabolites; clinical steady-state achieved after 5-7 days.
Norelgestromin: 15-20 hours; Ethinyl estradiol: 13-16 hours. Steady-state achieved within 7 days.
Renal 50-60% as glucuronide and sulfate conjugates of norethindrone and mestranol/metabolites; fecal 20-30% via biliary elimination.
Renal (∼40% as metabolites, <10% unchanged) and fecal (∼30% as metabolites); conjugated metabolites excreted in bile and undergo enterohepatic circulation.
Category C
Category C
Hormonal Contraceptive
Hormonal Contraceptive