Comparative Pharmacology
Head-to-head clinical analysis: NORLESTRIN 28 1 50 versus SYEDA.
Peer-Reviewed Evidence
Head-to-head clinical analysis: NORLESTRIN 28 1 50 versus SYEDA.
NORLESTRIN 28 1/50 vs SYEDA
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.
Syeda is a combination of drospirenone and ethinyl estradiol, a contraceptive that suppresses gonadotropins, primarily inhibiting ovulation; drospirenone has antimineralocorticoid and antiandrogenic activity.
One tablet orally once daily, each containing norethindrone 1 mg and ethinyl estradiol 50 mcg.
1 tablet (3 mg drospirenone / 0.02 mg ethinyl estradiol) orally once daily for 21 days, followed by 7 days of placebo tablets.
None Documented
None Documented
Norethindrone: 8 hours; ethinyl estradiol: 12-15 hours; steady state achieved within 5-10 days.
Terminal elimination half-life of 12-15 hours; allows twice-daily dosing for sustained therapeutic levels.
Norethindrone: 40% renal, 60% fecal; ethinyl estradiol: 40% renal, 60% fecal.
Urinary excretion (40-60% as unchanged drug and metabolites); biliary/fecal elimination accounts for 15-25%.
Category C
Category C
Oral Contraceptive
Oral Contraceptive