NYLIA 1/35
Clinical safety rating
cautionComprehensive clinical and safety monograph for NYLIA 1/35 (NYLIA 1/35).
Combination oral contraceptive consisting of norethindrone (a progestin) and ethinyl estradiol (an estrogen). Inhibits ovulation by suppressing gonadotropin release, increases viscosity of cervical mucus to impede sperm penetration, and alters endometrial lining.
| Metabolism | Ethinyl estradiol is metabolized primarily via CYP3A4; norethindrone is metabolized via reduction and glucuronidation, with some involvement of CYP3A4. |
| Excretion | Renal: 40-60% (as metabolites, mainly ethinyl estradiol glucuronide and sulfate conjugates and norethindrone metabolites). Biliary/fecal: 30-50% (as conjugates and metabolites). |
| Half-life | Norethindrone: 5-14 hours (mean ~8 hours); Ethinyl estradiol: 7-36 hours (mean ~14 hours). Clinically, steady-state is achieved within 5-7 days. |
| Protein binding | Norethindrone: 80-95% (mainly to SHBG and albumin). Ethinyl estradiol: 98-99% (mainly to albumin, induces SHBG synthesis). |
| Volume of Distribution | Norethindrone: ~4 L/kg (large Vd indicates extensive tissue distribution). Ethinyl estradiol: ~3 L/kg (distributes to breast, uterine, and hepatic tissues). |
| Bioavailability | Oral bioavailability: Norethindrone ~60-70% (due to first-pass metabolism); Ethinyl estradiol ~50-60% (susceptible to CYP3A4-induced metabolism). |
| Onset of Action | Oral: Onset of contraceptive effect occurs after 7 days of continuous dosing; peak serum concentrations for both components reached at 1-2 hours post-dose. |
| Duration of Action | Duration of contraceptive efficacy is 24 hours with once-daily dosing. Missed pills >12 hours reduce reliability. |
| Molecular Weight | 299.36 |
One tablet (norethindrone 1 mg/ethinyl estradiol 35 mcg) orally once daily for 21 days, followed by 7 days of placebo or no medication. Continuous sequential regimen.
| Dosage form | TABLET |
| Renal impairment | No specific dose adjustment recommended; use with caution in patients with renal impairment as limited data available. |
| Liver impairment | Contraindicated in Child-Pugh class B or C (moderate to severe hepatic impairment). For Child-Pugh class A, use with caution; no specific dose adjustment recommended. |
| Pediatric use | Use only after menarche; same dosing as adults (one tablet daily for 21 days, then 7 days off). Not indicated for premenarchal patients. |
| Geriatric use | Not typically used in postmenopausal women; no safety and efficacy established in geriatric population. Contraindicated in women over 35 who smoke heavily (≥15 cigarettes/day). |
| 1st trimester | Contraindicated due to risk of congenital defects; use only if no alternative and benefits outweigh risks. |
| 2nd trimester | Contraindicated due to potential adverse effects on fetal development. |
| 3rd trimester | Contraindicated near term; may cause neonatal withdrawal and respiratory depression. |
Clinical note
Comprehensive clinical and safety monograph for NYLIA 1/35 (NYLIA 1/35).
| Placental transfer | High; crosses placenta rapidly and achieves fetal concentrations similar to maternal levels. |
| Breastfeeding | Drug is excreted in breast milk; avoid use in breastfeeding mothers due to risk of sedation and respiratory depression in the infant. |
| Lactation Rating | L5 - Contraindicated |
| Teratogenic Risk | FDA Pregnancy Category X. First trimester: Increased risk of neural tube defects, congenital heart defects, and limb reduction defects due to progestin/estrogen exposure. Second and third trimesters: Risk of masculinization of female fetuses (progestin-induced pseudohermaphroditism) and potential for estrogen-related adverse effects; contraindicated in pregnancy. |
| Fetal Monitoring | Monitor for pregnancy status prior to initiation and during therapy (urine or serum hCG). Monitor for signs of thromboembolism, hypertension, and liver dysfunction in the mother. Fetal monitoring if inadvertent exposure occurs. |
| Fertility Effects | Transient suppression of ovulation upon initiation; rapid return to baseline fertility upon discontinuation. No long-term adverse effects on fertility. |
■ 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 most significant in women over 35 years. Women who use combination oral contraceptives should be strongly advised not to smoke.
| Serious Effects |
Hypersensitivity to any componentSevere renal impairmentSevere hepatic impairmentUncontrolled hypertensionHistory of drug abuse
| Precautions | Thrombotic disorders (venous thromboembolism, arterial thromboembolism, stroke, myocardial infarction): discontinue if signs/symptoms occur, Cigarette smoking increases risk of serious cardiovascular events, Increased risk of gallbladder disease, Hepatic neoplasia (benign and malignant) – discontinue if jaundice or liver abnormalities develop, Hypertension – monitor blood pressure, Glucose intolerance – monitor in diabetic patients, Headache/migraine – discontinue if new or worsening, Bleeding irregularities (breakthrough bleeding, amenorrhea), Depression – discontinue if severe |
| Food/Dietary | Grapefruit juice may increase ethinyl estradiol levels, potentially increasing side effects. High-fat meals may delay absorption of norethindrone/ethinyl estradiol but do not reduce overall efficacy. No specific food restrictions; may be taken with or without food. However, consistent timing is more important than with meals. |
| Clinical Pearls | Norethindrone/ethinyl estradiol (1 mg/35 mcg) is a monophasic combination oral contraceptive. It works primarily by suppressing ovulation. The 35 mcg ethinyl estradiol dose is standard; however, patients with estrogen-sensitive conditions (e.g., migraine with aura, history of thromboembolism) should avoid use. Advise patients to take at the same time daily to maintain efficacy. Missed pill management: if missed >24 hours, take missed pill as soon as remembered and use backup contraception for 7 days. Drug interactions: rifampin, certain anticonvulsants (phenytoin, carbamazepine), and some antibiotics (e.g., ampicillin, tetracyclines) may reduce contraceptive efficacy. |
| Patient Advice | Take one tablet daily at the same time, even if you do not have sex. Missing pills increases pregnancy risk. · If you miss a pill by less than 24 hours, take it as soon as you remember. If more than 24 hours, take the missed pill and use backup contraception (e.g., condoms) for 7 days. · You may experience spotting or nausea during the first few packs; this usually improves. · Smoking increases the risk of serious cardiovascular side effects (blood clots, stroke, heart attack), especially if you are over 35. Do not smoke while taking this medication. · Contact your healthcare provider if you experience severe leg pain/swelling, chest pain, shortness of breath, severe headache, or vision changes. · This medication does not protect against sexually transmitted infections (STIs). Use condoms for STI prevention. · Some medications (e.g., rifampin, certain seizure or HIV medicines) can make birth control pills less effective; inform your healthcare provider of all medications you take. |
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