Comparative Pharmacology
Head-to-head clinical analysis: LEVONORGESTREL AND ETHINYL ESTRADIOL AND ETHINYL ESTRADIOL versus STILPHOSTROL.
Peer-Reviewed Evidence
Head-to-head clinical analysis: LEVONORGESTREL AND ETHINYL ESTRADIOL AND ETHINYL ESTRADIOL versus STILPHOSTROL.
LEVONORGESTREL AND ETHINYL ESTRADIOL AND ETHINYL ESTRADIOL vs STILPHOSTROL
Comparing the clinical profiles, pharmacokinetic behaviors, and safety indices of these two therapeutic agents.
Combination hormonal contraceptive: ethinyl estradiol suppresses gonadotropin release, inhibiting ovulation; levonorgestrel alters cervical mucus and endometrial lining to prevent fertilization and implantation.
Synthetic nonsteroidal estrogen; binds to estrogen receptors, inducing tumor regression in hormone-sensitive cancers.
One tablet containing 0.1 mg levonorgestrel and 0.02 mg ethinyl estradiol (or 0.15 mg levonorgestrel and 0.03 mg ethinyl estradiol) orally once daily for 21 days, followed by 7 days of placebo or ethinyl estradiol 0.01 mg alone. For extended-cycle regimens, dosing may be continuous for up to 84 days.
0.5-1 mg/kg intravenously daily for 5 days, then 0.5 mg/kg intramuscularly weekly.
None Documented
None Documented
Levonorgestrel: ~25 hours; Ethinyl estradiol: ~13 hours. Steady-state achieved within 5-7 days; clinical efficacy maintained by daily dosing.
Terminal elimination half-life: 50-60 hours (range 40-80 hr) due to enterohepatic recirculation; clinical context: steady-state achieved in ~10-14 days
Levonorgestrel: 45% renal, 32% fecal; Ethinyl estradiol: 40% renal, 60% fecal. Both undergo enterohepatic recirculation.
Renal (primarily as glucuronide conjugates, 70-80%); fecal (biliary excretion of conjugates, 20-30%); <5% unchanged
Category D/X
Category C
Estrogen
Estrogen