Comparative Pharmacology
Head-to-head clinical analysis: ETHINYL ESTRADIOL AND NORELGESTROMIN versus STILPHOSTROL.
Peer-Reviewed Evidence
Head-to-head clinical analysis: ETHINYL ESTRADIOL AND NORELGESTROMIN versus STILPHOSTROL.
ETHINYL ESTRADIOL AND NORELGESTROMIN vs STILPHOSTROL
Comparing the clinical profiles, pharmacokinetic behaviors, and safety indices of these two therapeutic agents.
Combination contraceptive: estrogen (ethinyl estradiol) suppresses gonadotropin release via negative feedback on pituitary; progestin (norelgestromin) thickens cervical mucus and inhibits ovulation.
Synthetic nonsteroidal estrogen; binds to estrogen receptors, inducing tumor regression in hormone-sensitive cancers.
One transdermal patch (releasing 0.035 mg ethinyl estradiol and 0.150 mg norelgestromin per 24 hours) applied once weekly for 3 weeks, followed by 1 week patch-free.
0.5-1 mg/kg intravenously daily for 5 days, then 0.5 mg/kg intramuscularly weekly.
None Documented
None Documented
Ethinyl estradiol has a terminal elimination half-life of approximately 13-27 hours (mean ~17 hours). Norelgestromin has a terminal half-life of about 28 hours. These half-lives support once-weekly dosing of the transdermal system, achieving steady-state by the second application.
Terminal elimination half-life: 50-60 hours (range 40-80 hr) due to enterohepatic recirculation; clinical context: steady-state achieved in ~10-14 days
Ethinyl estradiol and norelgestromin are excreted primarily via urine and feces. Ethinyl estradiol undergoes extensive metabolism; about 40% is excreted in urine and 60% in feces as glucuronide and sulfate conjugates. Norelgestromin is metabolized to norgestrel and other metabolites; approximately 45% is excreted in urine and 35% in feces.
Renal (primarily as glucuronide conjugates, 70-80%); fecal (biliary excretion of conjugates, 20-30%); <5% unchanged
Category D/X
Category C
Estrogen
Estrogen