Comparative Pharmacology
Head-to-head clinical analysis: CYCLAFEM 7 7 7 versus MICROGESTIN 1 5 30.
Peer-Reviewed Evidence
Head-to-head clinical analysis: CYCLAFEM 7 7 7 versus MICROGESTIN 1 5 30.
CYCLAFEM 7/7/7 vs MICROGESTIN 1.5/30
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 norethindrone acetate (progestin) and ethinyl estradiol (estrogen). Suppresses gonadotropin secretion (FSH, LH) via negative feedback on hypothalamic-pituitary axis, preventing ovulation. Also increases cervical mucus viscosity and alters endometrial receptivity.
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 (norethindrone acetate 1.5 mg/ethinyl estradiol 30 mcg) orally once daily at the same time each day for 21 consecutive days, followed by 7 days of placebo tablets.
None Documented
None Documented
Terminal half-life: 5-13 hours (mean 8 hrs); clinical context: supports every-28-day dosing interval for intramuscular depot.
Norethindrone: 8-11 hours; Ethinyl estradiol: 13-19 hours. Steady-state reached within 5-7 days.
Renal: ~50-60% as conjugated metabolites; Fecal: ~30-40% via bile; <1% unchanged.
Renal: ~50-60% (primarily as glucuronide conjugates of ethinyl estradiol and norethindrone); Fecal: ~40-50% (via biliary elimination)
Category C
Category C
Oral Contraceptive
Oral Contraceptive