LARIN FE 1.5/30
Clinical safety rating
cautionComprehensive clinical and safety monograph for LARIN FE 1.5/30 (LARIN FE 1.5/30).
Combination oral contraceptive containing ethinyl estradiol (estrogen) and norethindrone (progestin). Suppresses gonadotropin release (FSH, LH) via negative feedback on hypothalamic-pituitary axis, inhibiting ovulation. Increases cervical mucus viscosity, reducing sperm penetration; alters endometrial receptivity. Norethindrone also decreases ovarian estrogen production.
| Metabolism | Ethinyl estradiol: primarily CYP3A4 metabolism with first-pass hepatic and intestinal metabolism; undergoes conjugation (glucuronidation and sulfation). Norethindrone: extensively metabolized via reduction, glucuronidation, and sulfation; CYP3A4 also involved. |
| Excretion | Ethinyl estradiol and norethindrone are primarily excreted via renal (urine) and fecal routes. Approximately 40-50% of ethinyl estradiol is excreted renally as metabolites, with 20-30% in feces. Norethindrone metabolites are excreted ~50-70% renally and 20-30% fecally. Less than 5% is excreted unchanged. |
| Half-life | Ethinyl estradiol terminal half-life is approximately 13-17 hours; norethindrone terminal half-life is approximately 7-10 hours. Steady-state is reached within 5-10 days. |
| Protein binding | Ethinyl estradiol: ~97-98% bound, primarily to albumin (70%) and sex hormone-binding globulin (SHBG). Norethindrone: ~61-63% bound, primarily to albumin and SHBG. |
| Volume of Distribution | Ethinyl estradiol: Vd approximately 2.5-4 L/kg; norethindrone: Vd approximately 4-5 L/kg. Distribution into breast milk and body fat is notable. |
| Bioavailability | Ethinyl estradiol: ~40-50% due to first-pass metabolism; norethindrone: ~50-65% with first-pass metabolism. Food may increase bioavailability. |
| Onset of Action | Oral administration: Contraceptive effect requires daily dosing; complete ovulation suppression occurs within 7 days if initiated on day 1 of menstrual cycle. |
| Duration of Action | Oral: Duration of contraceptive effect is 24 hours; requires daily dosing for maintenance. Missed dose increases pregnancy risk. |
| Molecular Weight | 360.5 |
| Action Class | Combination Oral Contraceptive (Estrogen-Progestin) |
One tablet orally once daily for 21 consecutive days, followed by 7 placebo tablets.
| Dosage form | TABLET |
| Renal impairment | Contraindicated in patients with renal impairment or renal disease. |
| Liver impairment | Contraindicated in patients with acute or chronic hepatic dysfunction (Child-Pugh class B or C). Use with caution in Child-Pugh class A, consider alternative therapy. |
| Pediatric use | Not indicated for use in pediatric females before menarche. For postmenarchal pediatric patients, dosage same as adults: one tablet orally once daily for 21 days, then 7 placebo tablets. |
| Geriatric use | Not indicated for use in postmenopausal women. Safety and efficacy not established in geriatric population. |
| 1st trimester | Contraindicated. Estrogens and progestins have been associated with congenital anomalies, including cardiovascular defects and limb reduction defects. Use during first trimester is contraindicated. |
| 2nd trimester | Contraindicated. Continued use during second trimester may increase risk of thromboembolic events and fetal harm. |
| 3rd trimester | Contraindicated. Use during third trimester may induce premature closure of the ductus arteriosus, neonatal hepatic dysfunction, and other fetal adverse effects. |
Clinical note
Comprehensive clinical and safety monograph for LARIN FE 1.5/30 (LARIN FE 1.5/30).
| Placental transfer | Both ethinyl estradiol and norethindrone cross the placenta. Ethinyl estradiol is extensively metabolized, but active metabolites can reach fetal circulation. Norethindrone shows significant placental transfer. |
| Breastfeeding | Excreted in breast milk in small amounts. May decrease milk production and quality. Use only if clearly needed, and monitor infant for jaundice and growth. Alternative contraception recommended. |
| Lactation Rating | L4 (Possibly Hazardous) |
| Teratogenic Risk | No increased risk of birth defects observed with oral contraceptives; avoid use in pregnancy due to potential for fetal harm and lack of necessity. First trimester: no consistent evidence of malformations. Second/third trimester: may cause fetal harm from estrogenic effects; discontinue if pregnancy occurs. |
| Fetal Monitoring | Monitor blood pressure, glucose, liver function, and signs of thromboembolism. In pregnancy, perform fetal ultrasound to assess growth if inadvertent exposure occurs. |
| Fertility Effects | Transiently inhibits ovulation; after discontinuation, return to fertility may be delayed but no long-term adverse effects on fertility. |
■ FDA Black Box Warning
Cigarette smoking increases risk of serious cardiovascular events (stroke, myocardial infarction, thromboembolism) from combined oral contraceptives. Risk increases with age and number of cigarettes smoked, particularly in women >35 years. Advise not to smoke.
| Common Effects | Nausea, Headache, Breast tenderness, Weight changes, Irregular uterine bleeding, Mood changes |
| Serious Effects | Venous thromboembolism (VTE), Arterial thromboembolism (e.g., stroke, myocardial infarction), Hepatic adenoma or hepatocellular carcinoma, Hypertension, Gallbladder disease, Cerebrovascular events |
Known or suspected pregnancyUndiagnosed abnormal uterine bleedingKnown or suspected breast cancerCurrent or history of thromboembolic disordersActive liver disease or impaired liver functionKnown hypersensitivity to any component
| Precautions | Increased risk of venous thromboembolism, arterial thrombosis, stroke, myocardial infarction, especially in smokers >35 years, hypertension, obesity, diabetes, hyperlipidemia, or migraine with aura. Monitor for undiagnosed abnormal genital bleeding, liver disease, hypertension, depression, migraine, carbohydrate/lipid effects, hereditary angioedema, chloasma, retinal thrombosis, gallbladder disease, and anaphylactic reactions. Discontinue if jaundice, vision changes, or severe headache occurs. |
| Food/Dietary | Grapefruit or grapefruit juice may increase ethinyl estradiol levels, potentially increasing side effects; avoid concurrent consumption. No specific dietary restrictions otherwise. Iron supplement in active tablets may cause GI upset; take with food to reduce irritation. |
| Clinical Pearls | Contains norethindrone 1.5 mg and ethinyl estradiol 30 mcg; low estrogen dose, suitable for women with estrogen sensitivity; iron supplement (ferrous fumarate 75 mg) in last 7 tablets helps prevent iron deficiency; missed pill protocol: if one tablet missed, take as soon as remembered; if two missed in week 1 or 2, take two the next day and two the day after; if two missed in week 3 or three or more missed at any time, discard pack and start new pack next day, use backup contraception for 7 days. |
| Patient Advice | Take one tablet daily at the same time, preferably after an evening meal to reduce nausea. · The last 7 tablets (brown) contain iron; do not skip them even if bleeding occurs. · If you miss a pill, refer to the missed pill instructions in the package insert. · Use backup contraception (e.g., condoms) if pills are missed or if you start a new pack late. · Common side effects include nausea, breast tenderness, and breakthrough bleeding, especially in the first 3 months. · Report severe abdominal pain, chest pain, shortness of breath, severe headache, or vision changes immediately. · Smoking increases risk of serious cardiovascular side effects; avoid smoking, especially if over 35. · This medication does not protect against sexually transmitted infections (STIs). |
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