Comparative Pharmacology
Head-to-head clinical analysis: NORLESTRIN 28 1 50 versus TRI LO SPRINTEC.
Peer-Reviewed Evidence
Head-to-head clinical analysis: NORLESTRIN 28 1 50 versus TRI LO SPRINTEC.
NORLESTRIN 28 1/50 vs TRI LO SPRINTEC
Comparing the clinical profiles, pharmacokinetic behaviors, and safety indices of these two therapeutic agents.
Combination estrogen-progestin oral contraceptive; suppresses gonadotropin release via negative feedback on pituitary, inhibits ovulation, thickens cervical mucus, alters endometrial receptivity.
Tri-Lo Sprintec is a combination oral contraceptive containing ethinyl estradiol and norgestimate. It inhibits ovulation by suppressing gonadotropin release (FSH and LH) from the pituitary, increases viscosity of cervical mucus, and alters endometrial receptivity.
One tablet orally once daily, each containing norethindrone 1 mg and ethinyl estradiol 50 mcg.
One tablet (0.035 mg ethinyl estradiol + 0.180/0.215/0.250 mg norgestimate) orally once daily for 28-day cycle: active tablets on days 1-21, placebo on days 22-28.
None Documented
None Documented
Norethindrone: 8 hours; ethinyl estradiol: 12-15 hours; steady state achieved within 5-10 days.
Ethinyl estradiol: terminal half-life approximately 17 hours. Norelgestromin (active metabolite of norgestimate): terminal half-life approximately 28 hours. Clinical context: Ethinyl estradiol half-life supports once-daily dosing with steady-state reached within 7-14 days; norelgestromin half-life allows for sustained progestogenic effect.
Norethindrone: 40% renal, 60% fecal; ethinyl estradiol: 40% renal, 60% fecal.
Renal (approximately 50-60% as metabolites, with about 20% as unchanged ethinyl estradiol glucuronide and 40% as norgestimate metabolites). Fecal (approximately 30-40% as metabolites).
Category C
Category C
Oral Contraceptive
Oral Contraceptive