Comparative Pharmacology
Head-to-head clinical analysis: CYCLAFEM 1 35 versus OGESTREL 0 5 50 21.
Peer-Reviewed Evidence
Head-to-head clinical analysis: CYCLAFEM 1 35 versus OGESTREL 0 5 50 21.
CYCLAFEM 1/35 vs OGESTREL 0.5/50-21
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 of norgestrel and ethinyl estradiol suppresses gonadotropin release, inhibiting ovulation; alters cervical mucus and endometrial lining.
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 (norgestrel 0.5 mg / ethinyl estradiol 0.05 mg) orally once daily for 21 days, followed by 7 placebo days.
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.
Norgestrel: 24-32 hours; Ethinyl estradiol: 7-12 hours. Clinical context: Steady state achieved after 5-7 days.
Renal 40-60% as glucuronide and sulfate conjugates, biliary/fecal 20-40%.
Renal: ~50% (metabolites); Fecal/Biliary: ~50% (metabolites); <1% unchanged in urine.
Category C
Category C
Oral Contraceptive
Oral Contraceptive