Comparative Pharmacology
Head-to-head clinical analysis: CYCLAFEM 1 35 versus NORINYL 1 80 21 DAY.
Peer-Reviewed Evidence
Head-to-head clinical analysis: CYCLAFEM 1 35 versus NORINYL 1 80 21 DAY.
CYCLAFEM 1/35 vs NORINYL 1+80 21-DAY
Comparing the clinical profiles, pharmacokinetic behaviors, and safety indices of these two therapeutic agents.
Combination oral contraceptive containing ethinyl estradiol and norethindrone. Suppresses gonadotropin (FSH, LH) secretion via estrogen and progestin negative feedback, inhibiting ovulation. Progestin alters cervical mucus (sperm penetration) and endometrial receptivity.
Combination oral contraceptive containing norethindrone (a progestin) and ethinyl estradiol (an estrogen). Inhibits ovulation by suppressing gonadotropin release (FSH and LH). Also increases cervical mucus viscosity and alters endometrial morphology.
One tablet orally once daily. Each tablet contains 1 mg norethindrone and 0.035 mg ethinyl estradiol. Administer daily for 21 days followed by 7 days of placebo or no tablet.
One tablet orally once daily for 21 days, followed by 7 days of no active treatment.
None Documented
None Documented
Half-life of norethindrone is 5-14 hours; ethinyl estradiol is 10-20 hours. Steady state reached after 5-7 days.
Norethindrone: 8-11 hours; Mestranol: 12-24 hours (metabolized to ethinyl estradiol with half-life 20-27 hours). Steady-state after 5-7 days.
Renal 40-60% as glucuronide and sulfate conjugates, biliary/fecal 20-40%.
Renal (40-60% as metabolites), fecal (20-30%)
Category C
Category C
Oral Contraceptive
Oral Contraceptive