Comparative Pharmacology
Head-to-head clinical analysis: CYCLAFEM 1 35 versus PHILITH.
Peer-Reviewed Evidence
Head-to-head clinical analysis: CYCLAFEM 1 35 versus PHILITH.
CYCLAFEM 1/35 vs PHILITH
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.
PHILITH is a combined oral contraceptive containing ethinyl estradiol and drospirenone. Ethinyl estradiol suppresses gonadotropin release, while drospirenone is a progestin with antiandrogenic and antimineralocorticoid activity, inhibiting ovulation and altering cervical mucus.
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.
1 mg orally once daily
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.
Terminal half-life 12 hours; clinically relevant for twice-daily dosing with steady state reached after 2-3 days.
Renal 40-60% as glucuronide and sulfate conjugates, biliary/fecal 20-40%.
Renal: 90% unchanged; biliary/fecal: 10% as metabolites.
Category C
Category C
Oral Contraceptive
Oral Contraceptive