Comparative Pharmacology
Head-to-head clinical analysis: ENOVID E versus ZOVIA 1 35E 28.
Peer-Reviewed Evidence
Head-to-head clinical analysis: ENOVID E versus ZOVIA 1 35E 28.
ENOVID-E vs ZOVIA 1/35E-28
Comparing the clinical profiles, pharmacokinetic behaviors, and safety indices of these two therapeutic agents.
Combination estrogen-progestin contraceptive. Suppresses gonadotropin release, inhibits ovulation, increases cervical mucus viscosity, and alters endometrial morphology.
ZOVIA 1/35E-28 is a combined oral contraceptive (COC) containing ethinyl estradiol and norethindrone. It inhibits ovulation via suppression of gonadotropins (FSH and LH), increases cervical mucus viscosity, and alters endometrial receptivity.
5 mg orally once daily for 20 days starting on day 5 of menstrual cycle
One tablet orally once daily at the same time each day for 21 days, followed by 7 days of placebo (inactive tablets), then repeat.
None Documented
None Documented
Norethynodrel: 5-10 hours; mestranol: 2-5 hours (metabolized to ethinyl estradiol, half-life 10-20 hours). Steady-state reached in 5-7 days.
Ethinyl estradiol: ~17 hours (range 13-27 hours); Norethindrone: ~8 hours (range 5-14 hours). Clinical context: Steady state achieved in ~5-7 days; contraceptive effect requires consistent dosing.
Renal (50-60% as metabolites, <1% unchanged); fecal (40-50%)
Renal: ~40% as metabolites; biliary/fecal: ~40% as metabolites; unchanged drug minimal (<1%).
Category C
Category C
Oral Contraceptive
Oral Contraceptive