OVCON-35
Clinical safety rating
cautionComprehensive 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. |
| Molecular Weight | 376.55 |
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 | Contraindicated in pregnancy. Use during the first trimester is associated with a slight increased risk of cardiovascular malformations and oral clefts. Estrogen-progestin combinations should not be used during pregnancy. |
| 2nd trimester | Contraindicated in pregnancy. Not indicated for use during the second trimester. There is a risk of adverse effects on fetal development. |
| 3rd trimester | Contraindicated in pregnancy. Use during the third trimester may be associated with adverse neonatal outcomes including respiratory distress and jaundice. |
Clinical note
Comprehensive clinical and safety monograph for OVCON-35 (OVCON-35).
| Placental transfer | Yes, estrogens and progestins cross the placenta. The degree of transfer is significant, and the drug can affect fetal development. |
| Breastfeeding | Excreted into breast milk in small amounts. Estrogens and progestins can reduce milk production and change milk composition. Use is generally not recommended during breastfeeding unless benefits outweigh risks. Monitor infant for signs of jaundice and breast enlargement. |
| Lactation Rating | L3 - Moderately Safe |
| 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 | 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. |
■ 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 |
PregnancyBreast cancer (current or history)Estrogen-dependent neoplasiaUndiagnosed abnormal genital bleedingKnown or suspected endometriosisActive liver disease or impaired liver functionThromboembolic disorders (current or history)Major surgery with prolonged immobilizationKnown hypersensitivity to any componentSmoking over age 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 |
| Food/Dietary | No specific food interactions. However, grapefruit juice may increase ethinyl estradiol levels by inhibiting CYP3A4; avoid excessive consumption. Cranberry juice may increase warfarin effect if taken concurrently, but no direct interaction with OVCON-35. Take with food or milk to reduce nausea. |
| Clinical Pearls | OVCON-35 is a combined oral contraceptive (COC) containing norethindrone 0.4 mg and ethinyl estradiol 35 mcg. It has higher progestin dose relative to estrogen, making it suitable for women with estrogen-related side effects. Monitor for breakthrough bleeding, particularly in early cycles. Contraindicated in women with BMI > 35 due to increased thromboembolic risk. Consider interaction with CYP450 inducers (e.g., rifampin) which may reduce contraceptive efficacy. Use with caution in migraine with aura due to stroke risk. |
| Patient Advice | Take one tablet daily at the same time to maintain hormone levels and prevent pregnancy. · If you miss a pill, follow the instructions in the package insert or consult your healthcare provider. Missing pills increases pregnancy risk. · Common side effects include nausea, breast tenderness, headache, and breakthrough bleeding. These often improve after 2-3 cycles. · This medication does not protect against sexually transmitted infections (STIs). Use barrier protection. · Inform your doctor of all medications, especially antibiotics, anticonvulsants, or St. John's Wort, as they may reduce effectiveness. · Seek immediate medical attention if you experience severe leg pain, chest pain, sudden shortness of breath, or severe headache (signs of blood clots or stroke). · Do not smoke while using this medication, especially if over 35 years old; smoking increases risk of serious cardiovascular side effects. |
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