Comparative Pharmacology
Head-to-head clinical analysis: NORLESTRIN FE 1 50 versus TRIPHASIL 21.
Peer-Reviewed Evidence
Head-to-head clinical analysis: NORLESTRIN FE 1 50 versus TRIPHASIL 21.
NORLESTRIN FE 1/50 vs TRIPHASIL-21
Comparing the clinical profiles, pharmacokinetic behaviors, and safety indices of these two therapeutic agents.
Combination of ethinyl estradiol and norethindrone acetate provides negative feedback on gonadotropin release, suppressing ovulation. Also causes cervical mucus thickening and endometrial thinning.
Combination of ethinyl estradiol and levonorgestrel suppresses gonadotropin release, inhibiting ovulation; alters cervical mucus to impair sperm penetration and endometrial receptivity.
One tablet (norethindrone 1 mg and ethinyl estradiol 50 mcg plus ferrous fumarate 75 mg) orally once daily for 28 days, with 21 active tablets and 7 placebo tablets.
One tablet orally daily for 21 days, followed by 7 drug-free days. Each tablet contains levonorgestrel 0.05 mg and ethinyl estradiol 0.03 mg (days 1-6), levonorgestrel 0.075 mg and ethinyl estradiol 0.04 mg (days 7-11), and levonorgestrel 0.125 mg and ethinyl estradiol 0.03 mg (days 12-21).
None Documented
None Documented
Norethindrone: 5-12 hours (mean 8 hours). Ethinyl estradiol: 11-16 hours. Clinical context: Steady state reached in 5-7 days.
Levonorgestrel: 10-45 hours (terminal, biphasic); ethinyl estradiol: 10-27 hours (terminal, triphasic). Clinical context: Steady state reached after 7-14 days with daily dosing.
Norethindrone: 20% renal, 80% fecal. Ethinyl estradiol: 40% renal, 60% fecal.
Renal: 30-50% (ethinyl estradiol and levonorgestrel metabolites as glucuronide and sulfate conjugates). Fecal: 30-50% (biliary excretion of unconjugated metabolites). Unchanged drug: negligible.
Category C
Category C
Oral Contraceptive
Oral Contraceptive