Comparative Pharmacology
Head-to-head clinical analysis: BREVICON 28 DAY versus CYCLAFEM 1 35.
Peer-Reviewed Evidence
Head-to-head clinical analysis: BREVICON 28 DAY versus CYCLAFEM 1 35.
BREVICON 28-DAY vs CYCLAFEM 1/35
Comparing the clinical profiles, pharmacokinetic behaviors, and safety indices of these two therapeutic agents.
Combination oral contraceptive; ethinyl estradiol and norethindrone suppress gonadotropin secretion (FSH and LH) via negative feedback, inhibiting ovulation. Additionally, alters cervical mucus consistency and endometrial lining to impede sperm penetration and implantation.
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.
One tablet (0.5 mg norethindrone and 35 mcg ethinyl estradiol) orally once daily for 28 days (21 active tablets followed by 7 inert tablets).
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.
None Documented
None Documented
Norethindrone: 8-11 hours; Ethinyl estradiol: 13-27 hours; half-life for ethinyl estradiol allows once-daily dosing
Half-life of norethindrone is 5-14 hours; ethinyl estradiol is 10-20 hours. Steady state reached after 5-7 days.
Renal: ~40% as metabolites and unchanged drug; fecal/biliary: ~60% as metabolites
Renal 40-60% as glucuronide and sulfate conjugates, biliary/fecal 20-40%.
Category C
Category C
Oral Contraceptive
Oral Contraceptive