Comparative Pharmacology
Head-to-head clinical analysis: NORGESTIMATE ETHINYL ESTRADIOL versus STILPHOSTROL.
Peer-Reviewed Evidence
Head-to-head clinical analysis: NORGESTIMATE ETHINYL ESTRADIOL versus STILPHOSTROL.
NORGESTIMATE; ETHINYL ESTRADIOL vs STILPHOSTROL
Comparing the clinical profiles, pharmacokinetic behaviors, and safety indices of these two therapeutic agents.
Combination oral contraceptive containing norgestimate (a progestin) and ethinyl estradiol (an estrogen). The primary mechanism is suppression of gonadotropins (FSH and LH) via negative feedback on the hypothalamic-pituitary-ovarian axis, preventing ovulation. Additional effects include thickening cervical mucus (inhibiting sperm penetration) and altering endometrial receptivity.
Synthetic nonsteroidal estrogen; binds to estrogen receptors, inducing tumor regression in hormone-sensitive cancers.
Oral, one tablet daily at the same time for 21 days, followed by 7 placebo tablets.
0.5-1 mg/kg intravenously daily for 5 days, then 0.5 mg/kg intramuscularly weekly.
None Documented
None Documented
Norgestimate: terminal half-life of norelgestromin (active metabolite) is 27.6 ± 7.8 hours; ethinyl estradiol: terminal half-life is 17.5 ± 6.3 hours. Steady state achieved within 14 days.
Terminal elimination half-life: 50-60 hours (range 40-80 hr) due to enterohepatic recirculation; clinical context: steady-state achieved in ~10-14 days
Norgestimate metabolites are primarily excreted via urine (60-80%) and feces (35-49%) as glucuronide and sulfate conjugates; ethinyl estradiol is excreted in urine (40%) and feces (60%) as conjugates.
Renal (primarily as glucuronide conjugates, 70-80%); fecal (biliary excretion of conjugates, 20-30%); <5% unchanged
Category D/X
Category C
Progestin + Estrogen
Estrogen