Comparative Pharmacology
Head-to-head clinical analysis: MICROGESTIN 1 20 versus PHILITH.
Peer-Reviewed Evidence
Head-to-head clinical analysis: MICROGESTIN 1 20 versus PHILITH.
MICROGESTIN 1/20 vs PHILITH
Comparing the clinical profiles, pharmacokinetic behaviors, and safety indices of these two therapeutic agents.
Combination oral contraceptive containing estrogen (ethinyl estradiol) and progestin (norethindrone acetate). Inhibits gonadotropin secretion (FSH, LH) via negative feedback, preventing ovulation. Also causes cervical mucus thickening and endometrial thinning.
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 (norethindrone acetate 1 mg / ethinyl estradiol 20 mcg) orally once daily for 21 consecutive days, followed by 7 days of placebo or no tablets.
1 mg orally once daily
None Documented
None Documented
Norethindrone: 5.2-12.8 hours (mean ~8 hours); Ethinyl estradiol: 7-20 hours (mean ~13 hours); hepatic impairment prolongs.
Terminal half-life 12 hours; clinically relevant for twice-daily dosing with steady state reached after 2-3 days.
Renal: 40% as metabolites, 20% as glucuronide and sulfate conjugates; Fecal: 35%; Biliary: <5%.
Renal: 90% unchanged; biliary/fecal: 10% as metabolites.
Category C
Category C
Oral Contraceptive
Oral Contraceptive