OVCON-35
Clinical safety rating: caution
Comprehensive clinical and safety monograph for OVCON-35 (OVCON-35).
Combination estrogen-progestin contraceptive; suppresses gonadotropin release, inhibiting ovulation, and increases cervical mucus viscosity, impeding sperm penetration.
| Metabolism | Ethinyl estradiol is primarily metabolized by CYP3A4; norethindrone is metabolized via reduction and sulfate conjugation, partly involving CYP3A4. |
| Excretion | Renal 60% (metabolites, glucuronide conjugates), fecal 10%, biliary 5%, remainder via other pathways. |
| Half-life | Ethinyl estradiol: 5-18 hours (mean ~12 hours, biphasic); norethindrone: 5-14 hours (mean ~8 hours). Terminal half-life relevant for once-daily dosing. |
| Protein binding | Ethinyl estradiol: 97-98% (mainly albumin, SHBG); norethindrone: 90-95% (albumin, SHBG). |
| Volume of Distribution | Ethinyl estradiol: 2-4 L/kg; norethindrone: 4-6 L/kg. Large Vd indicates extensive tissue distribution. |
| Bioavailability | Ethinyl estradiol: ~38-48% (first-pass metabolism); norethindrone: ~64% (range 47-73%). |
| Onset of Action | Oral: 24-48 hours for hormonal effects (follicle suppression, ovulation inhibition); full contraceptive effect after 7 days of continuous therapy. |
| Duration of Action | 24 hours (maintained with daily dosing); after discontinuation, ovulation returns within 1-2 months. |
One tablet (35 mcg ethinyl estradiol and 0.4 mg norethindrone) orally once daily.
| Dosage form | TABLET |
| Renal impairment | No dose adjustment required for mild-to-moderate renal impairment. Contraindicated in severe renal impairment (GFR <30 mL/min) due to risk of hyperkalemia. |
| Liver impairment | Contraindicated in severe hepatic disease (Child-Pugh Class C) and active liver disease. Use with caution in Child-Pugh Class A or B; dose adjustment not established. |
| Pediatric use | Safety and efficacy not established in children under 18 years. Postmenarchal adolescents: same as adult dosing, but weigh risks vs. benefits. |
| Geriatric use | Not typically used in postmenopausal women. Contraindicated in women over 60 due to increased risk of thromboembolic events and hypertension. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for OVCON-35 (OVCON-35).
| Breastfeeding | Contraindicated in breastfeeding. Estrogens and progestins are excreted in breast milk. M/P ratio not established. May reduce milk production and quality. |
| Teratogenic Risk | FDA Pregnancy Category X. First trimester: increased risk of neural tube defects, congenital heart defects, and limb reduction defects. Second and third trimesters: fetal feminization in males, vaginal adenosis in females, and other urogenital anomalies. Postnatal: increased risk of neurodevelopmental issues. |
| Fetal Monitoring |
■ FDA Black Box Warning
Cigarette smoking increases risk of serious cardiovascular events from combination oral contraceptive use. This risk increases with age and with heavy smoking (≥15 cigarettes/day). Women over 35 who smoke should not use combination oral contraceptives.
| Serious Effects |
["Thrombophlebitis or thromboembolic disorders","Cerebrovascular or coronary artery disease","Known or suspected breast cancer","Estrogen-dependent neoplasia","Undiagnosed abnormal genital bleeding","Pregnancy","Active liver disease or benign/malignant liver tumors","Heavy smoking in women over 35"]
| Precautions | ["Increased risk of thromboembolic disorders, myocardial infarction, stroke, and hepatic neoplasia","Discontinue if jaundice, visual disturbances, or migraine headaches develop","May cause fluid retention; use with caution in conditions that might be aggravated by fluid retention","May decrease glucose tolerance; monitor diabetic patients","May cause elevation in blood pressure","Hereditary angioedema may be exacerbated"] |
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| Monitor for fetal growth restriction via ultrasound. Assess for congenital anomalies with detailed anatomy scan at 18-20 weeks. Evaluate for maternal hypertension, thromboembolic events, and hepatic function. |
| Fertility Effects | Suppresses ovulation via inhibition of gonadotropin release. Reversible upon discontinuation. No long-term negative impact on fertility. May delay return to fertility for up to 1-2 cycles after cessation. |