LOESTRIN FE 1.5/30
Clinical safety rating
cautionComprehensive clinical and safety monograph for LOESTRIN FE 1.5/30 (LOESTRIN FE 1.5/30).
Suppresses gonadotropin (FSH and LH) release via estrogen and progestin feedback inhibition, preventing ovulation; increases cervical mucus viscosity and alters endometrial lining.
| Metabolism | Metabolized in liver via CYP3A4 (norethindrone) and hydroxylation/conjugation (ethinyl estradiol). |
| Excretion | Renal: ~50-60% (norethindrone metabolites); Fecal: ~20-30% (norethindrone); Ethinyl estradiol: primarily renal (~40-50%) and fecal (~20-50%) as glucuronide and sulfate conjugates. |
| Half-life | Norethindrone: ~5-14 hours (terminal); Ethinyl estradiol: ~13-27 hours (terminal). Clinically, steady-state achieved within 5-7 days. |
| Protein binding | Norethindrone: ~80-90% bound to SHBG and albumin; Ethinyl estradiol: ~95-98% bound primarily to albumin (with some to SHBG). |
| Volume of Distribution | Norethindrone: ~4 L/kg; Ethinyl estradiol: ~4-10 L/kg; indicates extensive tissue distribution. |
| Bioavailability | Oral: Norethindrone ~64%; Ethinyl estradiol ~38-48% (due to first-pass metabolism). |
| Onset of Action | Oral: Contraceptive effect achieved after 7 days of consecutive dosing; mid-cycle suppression of ovulation begins within 24-48 hours. |
| Duration of Action | 24 hours for contraceptive effect; daily dosing required. Withdrawal bleeding typically occurs 2-3 days after completion of active pills. |
| Molecular Weight | Ethinyl estradiol: 296.4 Da; Norethindrone acetate: 340.5 Da |
One tablet orally once daily at the same time each day for 21 consecutive days, followed by 7 days of placebo (ferrous fumarate) tablets, then restart.
| Dosage form | TABLET |
| Renal impairment | No dose adjustment required for renal impairment; however, use with caution in patients with impaired renal function due to potential fluid retention. |
| Liver impairment | Contraindicated in acute hepatic disease or liver tumors (benign or malignant). For Child-Pugh Class A, no dose adjustment; avoid use in Class B or C. |
| Pediatric use | Not indicated for use before menarche. For postmenarchal adolescents, same dosing as adults: one tablet orally once daily. |
| Geriatric use | Not indicated for use in postmenopausal women. No specific geriatric dosing. |
| 1st trimester | Contraindicated: Increased risk of cardiovascular events and fetal harm; combined hormonal contraceptives are not indicated during pregnancy. |
| 2nd trimester | Contraindicated: Associated with fetal risk; should not be used during pregnancy. |
| 3rd trimester | Contraindicated: May cause adverse fetal effects including potential androgenization of female fetus; avoid during pregnancy. |
Clinical note
Comprehensive clinical and safety monograph for LOESTRIN FE 1.5/30 (LOESTRIN FE 1.5/30).
| Placental transfer | Estrogen and progestin components cross the placenta; evidence from pharmacokinetic studies shows transfer to fetal circulation. |
| Breastfeeding | Excreted in breast milk; may reduce milk production and quality. Use alternative contraception if possible. Risk to infant unknown but potential for estrogenic effects. |
| Lactation Rating | L4 (Possibly Hazardous) |
| Teratogenic Risk | FDA Pregnancy Category X. Use contraindicated in pregnancy. First trimester: increased risk of neural tube defects, cardiovascular anomalies, and limb reduction defects. Second and third trimesters: associated with fetal harm, including masculinization of female fetuses due to progestin component. No safe use during pregnancy. |
| Fetal Monitoring | Pregnancy test before initiation. Monitor blood pressure, liver function, lipid profile, and glucose tolerance. Assess for thromboembolic events. Fetal monitoring: ultrasound if pregnancy occurs despite use. |
| Fertility Effects | Suppresses ovulation; after discontinuation, rapid return to baseline fertility expected. Transient delay in conception possible but no permanent impairment. |
■ FDA Black Box Warning
Cigarette smoking increases risk of serious cardiovascular events from combination oral contraceptive use; risk increases with age and heavy smoking (≥15 cigarettes/day) and is significant in women over 35. Women who use combination oral contraceptives should be strongly advised not to smoke.
| Serious Effects |
Known or suspected pregnancyBreast cancer (current or history)Estrogen-dependent neoplasiaUndiagnosed abnormal genital bleedingCurrent or history of thrombophlebitis or thromboembolic disordersCerebrovascular or coronary artery diseaseActive liver disease or hepatic tumorsKnown hypersensitivity to any componentMajor surgery with prolonged immobilizationSmoking over age 35Uncontrolled hypertensionDiabetes with vascular involvementMigraine with focal aura at any ageHistory of cholestatic jaundice with prior pill use
| Precautions | Increased risk of thromboembolic events; cardiovascular disease; hypertension; gallbladder disease; hepatic neoplasia; elevated liver enzymes; possible increased risk of breast/cervical cancer; glucose intolerance; fluid retention; hereditary angioedema; chloasma; irregular bleeding; depression; contact lens intolerance; possible reduced efficacy with enzyme-inducing drugs. |
| Food/Dietary | No significant food interactions. Grapefruit juice may slightly increase ethinyl estradiol levels but not clinically relevant. Separate iron tablets from high-calcium foods or supplements (e.g., dairy) to enhance iron absorption, but this does not affect contraceptive efficacy. |
| Clinical Pearls | Loestrin Fe 1.5/30 contains norethindrone acetate 1.5 mg and ethinyl estradiol 30 mcg plus ferrous fumarate (75 mg) as placebo pills. The iron supplement does not affect contraceptive efficacy. Be aware of increased risk of venous thromboembolism, especially in smokers over 35. Use with caution in patients with migraine with aura. Drug interactions with CYP3A4 inducers (e.g., rifampin, carbamazepine) may reduce efficacy. Breakthrough bleeding is common in first few cycles. Do not use in patients with hepatic impairment or known thrombophilia. |
| Patient Advice | Take one tablet daily at the same time each day, starting on the first day of menstrual bleeding. · The first 21 tablets are active hormones; the last 7 tablets are iron supplements that do not prevent pregnancy. · Missed dose: if you miss one active tablet, take it as soon as remembered; no backup needed. If you miss two, take two tablets and use backup contraception for 7 days. · Iron tablets may cause dark stools; this is harmless. · Report symptoms of blood clots: sudden leg pain, chest pain, shortness of breath, or severe headache. · Use additional contraception if starting within 5 days of stopping another hormonal contraceptive. · Avoid smoking while on this medication, especially if over 35. |
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