ENOVID-E
Clinical safety rating: caution
Comprehensive clinical and safety monograph for ENOVID-E (ENOVID-E).
Combination estrogen-progestin contraceptive. Suppresses gonadotropin release, inhibits ovulation, increases cervical mucus viscosity, and alters endometrial morphology.
| Metabolism | Metabolized via hepatic cytochrome P450 enzymes (CYP3A4) and conjugated with glucuronic acid and sulfate. Enterohepatic recirculation occurs. |
| Excretion | Renal (50-60% as metabolites, <1% unchanged); fecal (40-50%) |
| Half-life | Norethynodrel: 5-10 hours; mestranol: 2-5 hours (metabolized to ethinyl estradiol, half-life 10-20 hours). Steady-state reached in 5-7 days. |
| Protein binding | Norethynodrel: 95-98% (albumin); mestranol: 97-99% (albumin and SHBG) |
| Volume of Distribution | Norethynodrel: 2-4 L/kg; mestranol: 3-5 L/kg; extensive tissue distribution |
| Bioavailability | Oral: >90% for norethynodrel; mestranol: 40-60% (first-pass metabolism) |
| Onset of Action | Oral: 24-48 hours for contraceptive effect (requires 7 days of dosing for full inhibition of ovulation) |
| Duration of Action | Contraceptive effect persists for 1 month per cycle; after discontinuation, fertility returns within 1-2 cycles |
5 mg orally once daily for 20 days starting on day 5 of menstrual cycle
| Dosage form | TABLET |
| Renal impairment | No specific guidelines; use with caution in severe renal impairment (GFR <30 mL/min) due to potential fluid retention |
| Liver impairment | Contraindicated in severe hepatic disease (Child-Pugh class C); dose reduction recommended in moderate impairment (Child-Pugh class B: use lowest effective dose) |
| Pediatric use | Not approved for use in pediatric patients; safety and efficacy not established |
| Geriatric use | No specific dose adjustment; caution due to increased risk of thromboembolic events and fluid retention in elderly patients |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for ENOVID-E (ENOVID-E).
| Breastfeeding | Excreted in breast milk; M/P ratio not well established. Potential for adverse effects on infant including jaundice and breast enlargement. Avoid use during breastfeeding due to hormonal effects. |
| Teratogenic Risk | First trimester: Increased risk of neural tube defects, congenital heart defects, and limb reduction defects due to progestin and estrogen components. Second and third trimesters: Potential for feminization of male fetus, urogenital abnormalities, and possible long-term neurodevelopmental effects. Use contraindicated in pregnancy. |
■ FDA Black Box Warning
Cigarette smoking increases risk of serious cardiovascular events. Use contraindicated in women over 35 years who smoke.
| Serious Effects |
Thrombophlebitis or thromboembolic disorders, cerebrovascular or coronary artery disease, known or suspected breast carcinoma, endometrial carcinoma, undiagnosed abnormal genital bleeding, known or suspected pregnancy, hepatic adenoma or carcinoma, impaired liver function, and smokers over 35 years.
| Precautions | Increased risk of thromboembolic disorders, myocardial infarction, stroke, hepatic neoplasia, gallbladder disease, hypertension, and carbohydrate intolerance. Discontinue if jaundice, visual disturbances, or migraine occurs. Monitor blood pressure and liver function. |
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| Fetal Monitoring |
| Monitor fetal ultrasound for congenital anomalies if exposed inadvertently. Monitor maternal blood pressure, liver function, and signs of thromboembolism. Assess for fetal growth restriction and urogenital development. |
| Fertility Effects | May suppress ovulation and impair fertility during use. After discontinuation, return to fertility may be delayed but is generally reversible. Long-term use may affect endometrial receptivity. |