Comparative Pharmacology
Head-to-head clinical analysis: ETHINYL ESTRADIOL AND NORELGESTROMIN versus EVEX.
Peer-Reviewed Evidence
Head-to-head clinical analysis: ETHINYL ESTRADIOL AND NORELGESTROMIN versus EVEX.
ETHINYL ESTRADIOL AND NORELGESTROMIN vs EVEX
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.
Estrogen receptor agonist; binds to and activates nuclear estrogen receptors, leading to gene transcription and cellular effects in target tissues.
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.
0.625-1.25 mg orally once daily; or 0.3-0.625 mg vaginally once daily for 21 days with 7 days off.
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 is 12-24 hours, with a mean of approximately 18 hours. Due to significant enterohepatic recirculation, the half-life may be prolonged in patients with hepatic impairment or when administered with drugs that inhibit recirculation.
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.
Primarily hepatic metabolism with renal excretion of metabolites; approximately 60% of a dose is excreted in urine as conjugates (glucuronides and sulfates) and 30% in feces via biliary elimination. Less than 5% is excreted unchanged in urine.
Category D/X
Category C
Estrogen
Estrogen