Comparative Pharmacology
Head-to-head clinical analysis: CRYSELLE versus NORTREL 1 35 21.
Peer-Reviewed Evidence
Head-to-head clinical analysis: CRYSELLE versus NORTREL 1 35 21.
CRYSELLE vs NORTREL 1/35-21
Comparing the clinical profiles, pharmacokinetic behaviors, and safety indices of these two therapeutic agents.
Cryselle is a combination oral contraceptive containing ethinyl estradiol and norgestrel. It inhibits ovulation by suppressing gonadotropin release, primarily through estrogenic and progestogenic effects on the hypothalamic-pituitary axis. It also increases cervical mucus viscosity and alters endometrial structure, impeding sperm penetration and implantation.
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 (0.3 mg norgestrel/0.03 mg ethinyl estradiol) orally once daily at the same time each day for 21 consecutive days, followed by 7 days of placebo.
One tablet orally once daily for 21 days, followed by 7 days off, then repeat.
None Documented
None Documented
Terminal elimination half-life approximately 24 hours (range 16-36 h), with clinical significance for once-daily dosing.
Norethindrone: 5-14 hours; Ethinyl estradiol: 17-24 hours. Steady-state achieved after 10 days.
Renal (50% as metabolites, 20% unchanged), fecal (30%), with enterohepatic recirculation.
Renal 50-60% as metabolites, fecal 40-50% as conjugates, <1% unchanged
Category C
Category C
Oral Contraceptive
Oral Contraceptive