LARIN 1.5/30
Clinical safety rating
cautionComprehensive clinical and safety monograph for LARIN 1.5/30 (LARIN 1.5/30).
Combination oral contraceptive: ethinyl estradiol suppresses FSH and LH, preventing ovulation; norethindrone induces endometrial changes and increases cervical mucus viscosity, impeding sperm penetration.
| Metabolism | Ethinyl estradiol: primarily CYP3A4; norethindrone: primarily CYP3A4, with some reduction to active metabolites. |
| Excretion | Renal (40% as metabolites, <10% unchanged); fecal (50% as metabolites); biliary (minor). |
| Half-life | Ethinyl estradiol: 13-19 hours; Norethindrone: 7-9 hours. Steady-state achieved in ~5-7 days. |
| Protein binding | Ethinyl estradiol: 97-98% bound to albumin; Norethindrone: 93-99% bound to SHBG and albumin. |
| Volume of Distribution | Ethinyl estradiol: 2.5-5 L/kg; Norethindrone: 2-4 L/kg. Indicates extensive tissue distribution. |
| Bioavailability | Oral: Ethinyl estradiol ~40-50% (first-pass metabolism); Norethindrone ~50-60% (first-pass metabolism). |
| Onset of Action | Oral: contraceptive effect requires 7 days of continuous dosing; immediate if started on day 1 of menses. |
| Duration of Action | 24 hours for contraceptive efficacy; requires daily dosing for sustained effect. |
| Molecular Weight | Norgestimate: 369.50 Da; Ethinyl estradiol: 296.40 Da |
| Action Class | Combination Oral Contraceptive (Estrogen-Progestin) |
One tablet (norethindrone acetate 1.5 mg, ethinyl estradiol 30 mcg) orally once daily at the same time each day for 21 consecutive days, followed by 7 days of placebo tablets.
| Dosage form | TABLET |
| Renal impairment | No dose adjustment required in mild to moderate renal impairment (CrCl >=30 mL/min). Use contraindicated in severe renal impairment (CrCl <30 mL/min) or renal failure due to potential for fluid retention and hyperkalemia. |
| Liver impairment | Contraindicated in Child-Pugh class B or C (moderate to severe hepatic impairment). For Child-Pugh class A, lowest possible effective dose should be used with close monitoring of liver function. |
| Pediatric use | Post-menarche adolescents: same dosing as adults (one tablet daily for 21 days, then 7 days placebo). Safety and efficacy in pre-menarche girls have not been established. |
| Geriatric use | Not indicated for postmenopausal women. No specific geriatric dose adjustments; however, consider increased risk of thromboembolic events and cardiovascular disease in women aged >40 years who smoke or have other risk factors. |
| 1st trimester | Contraindicated due to risk of congenital anomalies, especially cardiovascular and neural tube defects. Use only if no alternative and after careful risk-benefit. |
| 2nd trimester | Contraindicated due to risk of fetal harm, including androgen effects and potential carcinogenesis. Avoid use. |
| 3rd trimester | Contraindicated due to risk of fetal harm, including androgenic effects and potential carcinogenesis. Avoid use. |
Clinical note
Comprehensive clinical and safety monograph for LARIN 1.5/30 (LARIN 1.5/30).
| Placental transfer | Norgestimate and ethinyl estradiol cross the placenta; active metabolites (norelgestromin) detected in fetal circulation. Significant transfer. |
| Breastfeeding | Excreted in human milk; potential for serious adverse reactions in nursing infants, including jaundice and feminization. Decision to discontinue nursing or drug based on importance of drug to mother. |
| Lactation Rating | L5 - Contraindicated |
| Teratogenic Risk | First trimester: No consistent evidence of major malformations, but a small increased risk of cardiovascular defects and oral clefts cannot be excluded. Second and third trimesters: Associated with adverse fetal outcomes including low birth weight, preterm delivery, and neonatal withdrawal symptoms. Avoid use during pregnancy due to known risks. |
| Fetal Monitoring | Monitor maternal blood pressure, blood glucose, and liver function. Assess fetal growth and well-being with ultrasound if prolonged exposure occurs. Evaluate for signs of thromboembolism. |
| Fertility Effects | Reversible suppression of ovulation; normal fertility typically returns upon discontinuation. No permanent negative impact on fertility. |
■ FDA Black Box Warning
Cigarette smoking increases risk of serious cardiovascular events. Risk increases with age and heavy smoking (≥15 cigarettes/day). Women over 35 who smoke should not use this product.
| Common Effects | Nausea, Headache, Breast tenderness, Weight changes, Irregular menstrual bleeding, Mood changes |
| Serious Effects | Venous thromboembolism (VTE), Arterial thromboembolism (e.g., stroke, myocardial infarction), Hepatic adenoma or hepatocellular carcinoma, Hypertension, Gallbladder disease, Retinal thrombosis |
PregnancyBreast cancer (known, suspected, or history)Active liver disease or liver tumorsThromboembolic disorders (current or history)Cerebrovascular or coronary artery diseaseUndiagnosed abnormal uterine bleedingHypersensitivity to any componentSmoking >35 years of age
| Precautions | Cardiovascular disease risk: smoking, hypertension, diabetes, hyperlipidemia, Thromboembolic events: increased risk in surgery, postpartum, or immobilization, Liver disease: discontinue if jaundice develops, Gallbladder disease: increased risk, Glucose intolerance: monitor in diabetics, Blood pressure elevation: monitor periodically, Depression: discontinue if severe |
| Food/Dietary | Grapefruit juice may increase ethinyl estradiol levels; avoid excessive consumption. No specific dietary restrictions; can be taken with or without food. |
| Clinical Pearls | Larin 1.5/30 is a monophasic combination oral contraceptive containing 1.5 mg norethindrone acetate and 30 mcg ethinyl estradiol. It is indicated for prevention of pregnancy and may also be used for management of acne and menstrual disorders. Advise patients to take at the same time daily to maintain consistent hormone levels. Counsel about breakthrough bleeding, especially during first cycles. Monitor for thrombotic events; use with caution in women with migraine with aura, hypertension, or smoking history over age 35. Effectiveness may be reduced with strong CYP3A4 inducers. Consider alternative contraception if patient is on chronic enzyme-inducing drugs. Use of NSAIDs can increase risk of breakthrough bleeding. Not recommended during breastfeeding or pregnancy. |
| Patient Advice | Take one tablet at the same time each day, with or without food. · If you miss a dose, follow the instructions in the package insert; use backup contraception if needed. · Common side effects include nausea, breast tenderness, headache, and breakthrough bleeding, especially in the first few months. · Seek medical attention if you experience leg pain, chest pain, shortness of breath, severe headache, vision changes, or jaundice. · Do not smoke while taking this medication as it increases the risk of serious cardiovascular side effects. · Inform your healthcare provider of all medications you are taking, including over-the-counter drugs and supplements. · This medication does not protect against sexually transmitted infections; use condoms for STI prevention. |
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