Comparative Pharmacology
Head-to-head clinical analysis: NORTREL 1 35 21 versus TRIPHASIL 21.
Peer-Reviewed Evidence
Head-to-head clinical analysis: NORTREL 1 35 21 versus TRIPHASIL 21.
NORTREL 1/35-21 vs TRIPHASIL-21
Comparing the clinical profiles, pharmacokinetic behaviors, and safety indices of these two therapeutic agents.
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.
Combination of ethinyl estradiol and levonorgestrel suppresses gonadotropin release, inhibiting ovulation; alters cervical mucus to impair sperm penetration and endometrial receptivity.
One tablet orally once daily for 21 days, followed by 7 days off, then repeat.
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: 5-14 hours; Ethinyl estradiol: 17-24 hours. Steady-state achieved after 10 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.
Renal 50-60% as metabolites, fecal 40-50% as conjugates, <1% unchanged
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