LOESTRIN FE 1.5/30
Clinical safety rating: caution
Comprehensive 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. |
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 | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for LOESTRIN FE 1.5/30 (LOESTRIN FE 1.5/30).
| Breastfeeding | Small amounts of ethinyl estradiol and norethindrone acetate excreted in breast milk; M/P ratio not reported. May reduce milk production and quality. Use only if clearly needed; lowest effective dose recommended. Caution in nursing mothers. |
| 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. |
■ 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 |
Thrombophlebitis or thromboembolic disorders; history of deep vein thrombosis or pulmonary embolism; 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 oral contraceptive use; hepatic adenoma or carcinoma; known or suspected pregnancy; hypersensitivity to any component; current or history of migraine with aura (age ≥35); heavy smoking (≥15 cigarettes/day) in women ≥35 years; uncontrolled hypertension; diabetes with vascular involvement; major surgery with prolonged immobilization; known thrombophilic conditions.
| 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. |
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| 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. |