Comparative Pharmacology
Head-to-head clinical analysis: GENCEPT 10 11 21 versus NORTREL 1 35 21.
Peer-Reviewed Evidence
Head-to-head clinical analysis: GENCEPT 10 11 21 versus NORTREL 1 35 21.
GENCEPT 10/11-21 vs NORTREL 1/35-21
Comparing the clinical profiles, pharmacokinetic behaviors, and safety indices of these two therapeutic agents.
GENCEPT 10/11-21 is a combination contraceptive vaginal ring containing ethinyl estradiol and etonogestrel. Ethinyl estradiol is an estrogen that suppresses gonadotropin release, inhibiting ovulation. Etonogestrel is a progestin that thickens cervical mucus, inhibiting sperm penetration, and alters the endometrium.
Combination of ethinyl estradiol (estrogen) and norethindrone (progestin) suppresses gonadotropin (FSH and LH) release from the pituitary, inhibiting ovulation, altering cervical mucus to impede sperm penetration, and inducing endometrial changes that reduce implantation likelihood.
One tablet (10 mg ethinyl estradiol and 11 mg gestodene on days 1-7, then placebo on days 8-21) orally once daily for 21 days, followed by 7 placebo days.
One tablet orally once daily for 21 days, followed by 7 days off, then repeat.
None Documented
None Documented
Terminal elimination half-life is 24-30 hours; allows once-daily dosing; steady-state achieved in 5-7 days
Norethindrone: 5-14 hours; Ethinyl estradiol: 17-24 hours. Steady-state achieved after 10 days.
Renal (30-40% as unchanged drug and metabolites), biliary/fecal (50-60% as metabolites)
Renal 50-60% as metabolites, fecal 40-50% as conjugates, <1% unchanged
Category C
Category C
Oral Contraceptive
Oral Contraceptive