Comparative Pharmacology
Head-to-head clinical analysis: NORTREL 1 35 21 versus TRI NORINYL 21 DAY.
Peer-Reviewed Evidence
Head-to-head clinical analysis: NORTREL 1 35 21 versus TRI NORINYL 21 DAY.
NORTREL 1/35-21 vs TRI-NORINYL 21-DAY
Comparing the clinical profiles, pharmacokinetic behaviors, and safety indices of these two therapeutic agents.
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.
Combination oral contraceptive containing ethinyl estradiol and norethindrone. Ethinyl estradiol suppresses gonadotropin release via negative feedback on hypothalamic-pituitary axis; norethindrone induces progestational effects, increases viscosity of cervical mucus, alters endometrial morphology, and inhibits ovulation.
One tablet orally once daily for 21 days, followed by 7 days off, then repeat.
One tablet (35 mcg ethinyl estradiol, 0.5 mg norethindrone for 7 days, 1 mg norethindrone for 9 days, 0.5 mg norethindrone for 5 days) orally once daily for 21 days, then 7 days off. Start on first day of menstrual period or first Sunday after onset.
None Documented
None Documented
Norethindrone: 5-14 hours; Ethinyl estradiol: 17-24 hours. Steady-state achieved after 10 days.
Norethindrone: 5-14 hours; Ethinyl estradiol: 17-23 hours. Steady-state reached within 5-7 days; clinical relevance for missed dose timing and resumption of ovulation.
Renal 50-60% as metabolites, fecal 40-50% as conjugates, <1% unchanged
Renal: ~50-60% (as metabolites); Fecal: ~30-40% (via bile); unchanged drug <1%.
Category C
Category C
Oral Contraceptive
Oral Contraceptive