Comparative Pharmacology
Head-to-head clinical analysis: NORINYL 1 80 28 DAY versus PHILITH.
Peer-Reviewed Evidence
Head-to-head clinical analysis: NORINYL 1 80 28 DAY versus PHILITH.
NORINYL 1+80 28-DAY vs PHILITH
Comparing the clinical profiles, pharmacokinetic behaviors, and safety indices of these two therapeutic agents.
Combination oral contraceptive containing a progestin (norethindrone) and an estrogen (mestranol). Suppresses gonadotropin (FSH and LH) release via negative feedback, inhibiting ovulation. Also induces changes in cervical mucus and endometrium to impede sperm penetration and implantation.
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 (1 mg norethindrone / 80 mcg ethinyl estradiol) orally once daily for 28-day cycle without placebo.
1 mg orally once daily
None Documented
None Documented
Norethindrone: terminal elimination half-life of 5.3-10.5 hours; Mestranol (as ethinyl estradiol): terminal half-life of 7-20 hours. Clinically, steady state is achieved after 5-7 days of daily dosing; the half-life supports once-daily dosing for consistent hormonal levels.
Terminal half-life 12 hours; clinically relevant for twice-daily dosing with steady state reached after 2-3 days.
Norethindrone is primarily excreted in urine (approximately 60%) and feces (approximately 40%) as glucuronide and sulfate conjugates. Mestranol is metabolized to ethinyl estradiol; ethinyl estradiol and its metabolites are excreted in urine (40%) and feces (60%).
Renal: 90% unchanged; biliary/fecal: 10% as metabolites.
Category C
Category C
Oral Contraceptive
Oral Contraceptive