Comparative Pharmacology
Head-to-head clinical analysis: DEMULEN 1 50 21 versus DEMULEN 1 50 28.
Peer-Reviewed Evidence
Head-to-head clinical analysis: DEMULEN 1 50 21 versus DEMULEN 1 50 28.
DEMULEN 1/50-21 vs DEMULEN 1/50-28
Comparing the clinical profiles, pharmacokinetic behaviors, and safety indices of these two therapeutic agents.
DEMULEN 1/50-21 is a combined oral contraceptive containing ethinyl estradiol and ethynodiol diacetate. Ethinyl estradiol and progestins inhibit gonadotropin release (FSH and LH) from the pituitary, suppressing ovulation. Progestins also increase cervical mucus viscosity and alter endometrial receptivity, impeding sperm penetration and implantation.
Combination oral contraceptive: Ethinyl estradiol and ethynodiol diacetate suppress gonadotropin secretion (LH, FSH) via negative feedback, inhibiting ovulation. Ethynodiol diacetate also increases cervical mucus viscosity and induces endometrial changes.
1 tablet (ethinyl estradiol 50 mcg, norethindrone 1 mg) orally once daily for 21 days, followed by 7 days off.
One tablet orally once daily for 28 consecutive days per cycle.
None Documented
None Documented
Ethinylestradiol: 13 ± 3 h (biphasic; terminal phase used for dosing interval). Clinical context: steady-state achieved after ~3 days; missed dose may reduce contraceptive efficacy if >36 h.
Ethinylestradiol: terminal elimination half-life ~13-27 hours (mean ~17 hours); ethynodiol diacetate (as norethindrone): terminal elimination half-life ~8-11 hours; clinical context: achieved steady-state within 5-10 days; accumulation not significant due to dose interval.
Renal (approx. 50% as metabolites, <1% unchanged), fecal (approx. 40%, largely as ethinylestradiol conjugates), biliary (minor, enterohepatic recirculation of ethinylestradiol)
Ethinylestradiol and ethynodiol diacetate are extensively metabolized; urinary excretion accounts for ~40% of ethinylestradiol metabolites and ~50-60% of ethynodiol diacetate metabolites; fecal excretion accounts for ~30% of ethinylestradiol metabolites and ~35% of ethynodiol diacetate metabolites; biliary excretion contributes to enterohepatic circulation.
Category C
Category C
Combination Oral Contraceptive
Combination Oral Contraceptive