Comparative Pharmacology
Head-to-head clinical analysis: AFIRMELLE versus LOESTRIN 21 1 20.
Peer-Reviewed Evidence
Head-to-head clinical analysis: AFIRMELLE versus LOESTRIN 21 1 20.
AFIRMELLE vs LOESTRIN 21 1/20
Comparing the clinical profiles, pharmacokinetic behaviors, and safety indices of these two therapeutic agents.
Combination oral contraceptive containing ethinyl estradiol and levonorgestrel. Inhibits ovulation by suppressing gonadotropin release (FSH and LH). Also increases cervical mucus viscosity and alters endometrial receptivity.
Combination estrogen-progestin contraceptive; suppresses gonadotropin secretion (FSH, LH) via negative feedback, inhibiting ovulation; increases cervical mucus viscosity and alters endometrial receptivity.
One tablet (0.1 mg levonorgestrel, 0.02 mg ethinyl estradiol) orally once daily for 21 days, followed by 7 days of placebo.
One tablet orally once daily for 21 days, then 7 days off. Each tablet contains norethindrone acetate 1 mg and ethinyl estradiol 20 mcg.
None Documented
None Documented
Terminal elimination half-life: 12–15 hours. Steady-state achieved within 5 days with Q12H dosing.
Norethindrone: 8-11 hours (terminal half-life; steady-state achieved after 5-10 days); Ethinyl estradiol: 13-27 hours (terminal half-life; significant interindividual variability due to enterohepatic recirculation).
Renal: 50% as unchanged drug and metabolites; fecal: 40% as metabolites; biliary: ~10% as glucuronide conjugates.
Renal: ~50% (as metabolites, primarily glucuronide conjugates of norethindrone and ethinyl estradiol); Fecal: ~35% (via bile); Urinary recovery of unchanged drug is minimal (<1%).
Category C
Category C
Combined Oral Contraceptive
Combined Oral Contraceptive