LOESTRIN 21 1.5/30
Clinical safety rating
cautionComprehensive clinical and safety monograph for LOESTRIN 21 1.5/30 (LOESTRIN 21 1.5/30).
Combination estrogen-progestin contraceptive: suppresses gonadotropin release, inhibiting ovulation; increases viscosity of cervical mucus, impeding sperm penetration; alters endometrial morphology.
| Metabolism | Ethinyl estradiol undergoes CYP3A4-mediated hydroxylation and conjugation; norethindrone undergoes reduction, sulfate conjugation, and CYP3A4 metabolism. |
| Excretion | Primarily hepatic metabolism; ~40-60% renal, 20-30% biliary/fecal. |
| Half-life | Ethinyl estradiol: ~12-14 h; Norethindrone: ~5-12 h. Steady-state achieved in ~5-10 days. |
| Protein binding | Ethinyl estradiol: ~97-98% (albumin); Norethindrone: ~80-90% (SHBG & albumin). |
| Volume of Distribution | Ethinyl estradiol: ~1.2-1.8 L/kg; Norethindrone: ~3.4 L/kg. Suggests extensive tissue distribution. |
| Bioavailability | Oral: Ethinyl estradiol ~38-48%, Norethindrone ~64-71% due to first-pass metabolism. |
| Onset of Action | Oral: 24-48 h for contraceptive effect; requires 7-day continuous dosing for full suppression. |
| Duration of Action | Contraceptive protection for duration of dosing; withdrawal bleed within 2-3 days post-dose. Weekly cyclic schedule required. |
| Molecular Weight | 376.5 |
One tablet (norethindrone acetate 1.5 mg/ethinyl estradiol 30 mcg) orally once daily for 21 consecutive days, followed by 7 days off therapy.
| Dosage form | TABLET |
| Renal impairment | No dosage adjustment required for mild-to-moderate renal impairment. Not recommended in patients with severe renal impairment or end-stage renal disease due to limited data. |
| Liver impairment | Contraindicated in patients with acute or chronic hepatic disease, including Child-Pugh class A, B, or C. Do not use. |
| Pediatric use | Safety and efficacy have not been established in postmenarchal adolescents. Use same dosing as adults after menarche if deemed appropriate by clinician; weight-based dosing not applicable. |
| Geriatric use | Not indicated for postmenopausal women. No specific geriatric dosing; avoid use in this population. |
| 1st trimester | Contraindicated due to risk of congenital anomalies (e.g., cardiovascular, limb defects) associated with estrogen/progestin exposure during organogenesis. Use only if necessary and with careful monitoring. |
| 2nd trimester | Avoid; no data supporting safety. Potential risk of fetal harm, including possible effects on development. Use alternative contraception. |
| 3rd trimester | Avoid; may cause adverse effects such as jaundice, reversible liver toxicity, or hormonal disruption in the neonate. Contraindicated in pregnancy. |
Clinical note
Comprehensive clinical and safety monograph for LOESTRIN 21 1.5/30 (LOESTRIN 21 1.5/30).
| Placental transfer | Estrogenic and progestogenic components cross the placenta; documented in animal and human studies. Transfer is significant and can cause fetal exposure. |
| Breastfeeding | Excreted into breast milk in small amounts; may reduce milk production and quality. Use during breastfeeding only if clearly needed and with caution; monitor infant for jaundice, growth, and development. |
| Lactation Rating | L3 (Moderately Safe) |
| Teratogenic Risk | No increased risk of birth defects based on epidemiological studies; postmarketing reports of congenital anomalies (limb defects, cardiovascular malformations) are rare and lack consistent association. Hormonal effects may cause fetal harm if used inadvertently during pregnancy; pregnancy should be excluded before initiation. Discontinue if pregnancy occurs. |
| Fetal Monitoring | Confirm negative pregnancy test before starting; monitor blood pressure, liver function, and signs of thromboembolism. In pregnant patients inadvertently exposed, no specific fetal monitoring required beyond routine prenatal care. |
| Fertility Effects | Suppresses ovulation via gonadotropin inhibition; after discontinuation, normal ovulatory cycles typically resume within 1-3 months. No evidence of permanent fertility impairment. |
■ FDA Black Box Warning
Cigarette smoking increases risk of serious cardiovascular events from combined hormonal contraceptive use; risk increases with age and number of cigarettes smoked; women over 35 who smoke should not use this product.
| Serious Effects |
PregnancyThrombophlebitis or thromboembolic disordersCerebrovascular or coronary artery diseaseKnown or suspected breast carcinomaUndiagnosed abnormal genital bleedingCholestatic jaundice of pregnancy or jaundice with prior pill useHepatic adenoma or carcinomaActive liver diseaseKnown hypersensitivity to components
| Precautions | Thrombotic disorders (venous thromboembolism, arterial thromboembolism, stroke, myocardial infarction), Hypertension, Gallbladder disease, Hepatic neoplasia, Carbohydrate/lipid effects, Headache/migraine, Irregular bleeding/amenorrhea, Drug interactions (e.g., antibiotics, anticonvulsants), Depression, Retinal thrombosis |
| Food/Dietary | No specific food restrictions. Grapefruit may increase estrogen levels; monitor for side effects. Avoid St. John's Wort as it reduces contraceptive efficacy. |
| Clinical Pearls | Start on first day of menses or first Sunday after onset. Use backup contraception for 7 days if starting after day 5. Monitor for thromboembolic events, especially in smokers over 35. May cause breakthrough bleeding; counsel that this usually resolves after 3 cycles. Consider drug interactions with rifampin, some anticonvulsants, and St. John's Wort. |
| Patient Advice | Take one tablet daily at the same time for 21 days, then none for 7 days. · Use backup contraception (e.g., condoms) if you miss a pill or start late. · Common side effects include nausea, breast tenderness, and spotting. · Seek medical attention for leg pain/swelling, chest pain, or sudden severe headache. · Do not smoke while taking this medication due to increased risk of blood clots. |
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