MICROGESTIN FE 1.5/30
Clinical safety rating: caution
Comprehensive clinical and safety monograph for MICROGESTIN FE 1.5/30 (MICROGESTIN FE 1.5/30).
Combination oral contraceptive: ethinyl estradiol (estrogen) and norethindrone acetate (progestin) suppress gonadotropin (FSH, LH) release, preventing ovulation; increase cervical mucus viscosity, inhibiting sperm penetration; alter endometrial development, reducing implantation likelihood.
| Metabolism | Ethinyl estradiol: primarily metabolized via CYP3A4; undergoes first-pass metabolism in gut and liver. Norethindrone acetate: deacetylated to norethindrone, metabolized mainly via reduction and conjugation (glucuronidation, sulfation), partly by CYP3A4. |
| Excretion | Norethindrone: 50-60% renal (as metabolites), 20-40% fecal; Ethinyl estradiol: ~40% renal, ~60% fecal (as glucuronide/sulfate conjugates). |
| Half-life | Norethindrone: 6-8 hours (terminal); Ethinyl estradiol: 12-18 hours (terminal). Clinical context: Steady-state achieved within 5-7 days; dosing interval suitable for once-daily administration. |
| Protein binding | Norethindrone: ~97% albumin and SHBG; Ethinyl estradiol: ~98% albumin (induces SHBG synthesis). |
| Volume of Distribution | Norethindrone: 2-5 L/kg (wide distribution, including breast tissue and adipose); Ethinyl estradiol: 2-4 L/kg (extensive distribution into reproductive tissues). |
| Bioavailability | Norethindrone: ~64% (oral, first-pass metabolism); Ethinyl estradiol: ~40-45% (oral, first-pass metabolism). |
| Onset of Action | Oral: 24-48 hours for contraceptive effect via suppression of ovulation (requires 7 consecutive days for full hypothalamic-pituitary-ovarian axis suppression). |
| Duration of Action | 24 hours (contraceptive efficacy maintained with daily dosing; breakthrough bleeding risk if dose missed >12 hours). |
One tablet (norethindrone acetate 1.5 mg, ethinyl estradiol 30 mcg) orally once daily for 28-day cycles (21 active tablets + 7 ferrous fumarate tablets).
| Dosage form | TABLET |
| Renal impairment | No dose adjustment required for mild to moderate renal impairment (eGFR ≥30 mL/min/1.73 m²). Not recommended in severe impairment (eGFR <30 mL/min/1.73 m²) due to limited data. |
| Liver impairment | Contraindicated in Child-Pugh class B or C (moderate to severe hepatic impairment). For Child-Pugh class A (mild impairment), use with caution; no specific dose adjustment established, but may increase risk of adverse effects. |
| Pediatric use | Approved for postmenarcheal adolescents. Dose same as adults: one tablet orally once daily for 28-day cycles. Not indicated for premenarcheal patients. |
| Geriatric use | Not indicated for use in women over 65 years due to lack of efficacy and safety data; increased risk of thromboembolic events and cardiovascular disease outweighs potential benefit. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for MICROGESTIN FE 1.5/30 (MICROGESTIN FE 1.5/30).
| Breastfeeding | Small amounts of ethinyl estradiol and norethindrone acetate are excreted in breast milk (estimated ~0.1% of maternal dose). M/P ratio not established. No adverse effects on nursing infant or milk production reported with combined oral contraceptives; however, WHO recommends avoiding combined OCs during lactation until weaning or at least 6 months postpartum due to theoretical risk of estrogen affecting milk production. Use caution; consider progestin-only alternative. |
| Teratogenic Risk | FDA Pregnancy Category X. First trimester: No increased risk of major birth defects from inadvertent use, but post-fertilization effects are theoretical. Contraindicated in pregnancy due to estrogen component and progestin exposure. Second/third trimester: Irrelevant as drug is contraindicated; no fetal exposure studies. Use in pregnancy may cause fetal harm: possible congenital anomalies (limb defects, heart defects) and adverse outcomes (low birth weight, premature birth, neonatal withdrawal) with prolonged exposure. |
■ FDA Black Box Warning
Cigarette smoking increases risk of serious cardiovascular events from combination oral contraceptives. Risk increases with age and heavy smoking (>=15 cigarettes/day). Women >=35 who smoke should not use this product.
| Serious Effects |
["Thrombophlebitis or thromboembolic disorders","History of DVT/PE","Cerebrovascular or coronary artery disease","Known or suspected breast carcinoma","Carcinoma of endometrium or other estrogen-dependent neoplasia","Undiagnosed abnormal genital bleeding","Cholestatic jaundice of pregnancy or jaundice with prior pill use","Hepatic adenoma/carcinoma","Known or suspected pregnancy","Hypersensitivity to any component","Smoking in women >=35 years","Uncontrolled hypertension","Diabetes with vascular involvement","Major surgery with prolonged immobilization"]
| Precautions | ["Thrombotic disorders (venous thromboembolism, arterial thrombosis, stroke, MI)","Carcinoma of breast/cervix","Hepatic disease (jaundice, tumors)","Elevated blood pressure","Gallbladder disease","Carbohydrate/lipid effects","Headache/migraine","Vaginal bleeding irregularities","Depression","Hereditary angioedema","Chloasma","Pregnancy loss"] |
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| Fetal Monitoring | If inadvertently used during pregnancy, discontinue immediately. Perform ultrasound for fetal anatomy and growth monitoring. No routine monitoring required in non-pregnant women; however, in women of reproductive potential, ensure pregnancy test prior to initiation and monthly monitoring of blood pressure, weight, and adverse effects. Consider liver function tests if symptoms of hepatic impairment. |
| Fertility Effects | Suppresses ovulation via negative feedback on gonadotropins. Returns to normal ovulation within 1-2 cycles after discontinuation. No permanent negative impact on fertility; can be used for cycle regulation. Reversible impairment of fertility due to anovulation while on therapy. |