Comparative Pharmacology
Head-to-head clinical analysis: CYCLAFEM 7 7 7 versus TRI NORINYL 28 DAY.
Peer-Reviewed Evidence
Head-to-head clinical analysis: CYCLAFEM 7 7 7 versus TRI NORINYL 28 DAY.
CYCLAFEM 7/7/7 vs TRI-NORINYL 28-DAY
Comparing the clinical profiles, pharmacokinetic behaviors, and safety indices of these two therapeutic agents.
Combination estrogen-progestin contraceptive. Ethinyl estradiol suppresses gonadotropin release (FSH, LH) via negative feedback on hypothalamic-pituitary axis; norethindrone induces endometrial changes that inhibit implantation and thickens cervical mucus.
Combination oral contraceptive containing ethinyl estradiol and norethindrone. Suppresses gonadotropin (FSH and LH) release via negative feedback, inhibiting ovulation. Also increases viscosity of cervical mucus and alters endometrial lining to reduce implantation likelihood.
One tablet (norethindrone 0.5 mg/ethinyl estradiol 35 mcg) orally once daily for 7 days, then one tablet (norethindrone 0.75 mg/ethinyl estradiol 35 mcg) orally once daily for 7 days, then one tablet (norethindrone 1 mg/ethinyl estradiol 35 mcg) orally once daily for 7 days. Dispensed in a 21-tablet pack with 7 placebo tablets. For contraception, take one tablet daily at same time each day for 28 days; begin next pack after 28-day cycle.
One tablet orally once daily for 21 days, followed by one placebo tablet orally once daily for 7 days. Each active tablet contains 0.035 mg ethinyl estradiol and 0.5 mg norethindrone (7 days), 0.035 mg ethinyl estradiol and 1.0 mg norethindrone (9 days), and 0.035 mg ethinyl estradiol and 0.5 mg norethindrone (5 days).
None Documented
None Documented
Terminal half-life: 5-13 hours (mean 8 hrs); clinical context: supports every-28-day dosing interval for intramuscular depot.
Ethinyl estradiol: 17 ± 6 hours (terminal); Norethindrone: 10 ± 3 hours (terminal). Steady-state achieved after 7-14 days.
Renal: ~50-60% as conjugated metabolites; Fecal: ~30-40% via bile; <1% unchanged.
Renal: 40% as metabolites; Fecal: 50% as metabolites; Biliary: minor; unchanged ethinyl estradiol excreted in urine <5%, norethindrone <1%.
Category C
Category C
Oral Contraceptive
Oral Contraceptive