NORLUTIN
Clinical safety rating: caution
Comprehensive clinical and safety monograph for NORLUTIN (NORLUTIN).
Synthetic progestin that binds to progesterone receptors, suppressing gonadotropin secretion and altering endometrial lining.
| Metabolism | Hepatic metabolism primarily via CYP3A4 reduction and conjugation. |
| Excretion | Mainly renal as glucuronide and sulfate conjugates; approximately 70% renal, 30% fecal/biliary. |
| Half-life | Terminal elimination half-life: 5–14 hours (mean ~8 hours). Clinical context: short half-life necessitates daily dosing for contraceptive efficacy. |
| Protein binding | ~80% bound to albumin; also binds to sex hormone-binding globulin (SHBG). |
| Volume of Distribution | Apparent Vd: ~4 L/kg; reflects distribution into total body water and extensive tissue binding. |
| Bioavailability | Oral bioavailability: ~65% (range 40–100%) due to first-pass metabolism; not administered by other routes. |
| Onset of Action | Oral: peak plasma levels reached 1–2 hours after administration; clinical contraceptive effect requires 48–72 hours of consistent dosing. |
| Duration of Action | Duration: ~24 hours for contraceptive effect based on daily dosing schedule; hence need for strict adherence. |
5 mg orally three times daily for endometriosis; 5 mg orally daily from day 5 to day 25 of menstrual cycle for amenorrhea.
| Dosage form | TABLET |
| Renal impairment | No specific dose adjustment guidelines; use with caution in severe renal impairment. |
| Liver impairment | Contraindicated in severe hepatic disease; reduce dose in mild to moderate impairment (Child-Pugh A/B). |
| Pediatric use | Not recommended for use in pediatric patients. |
| Geriatric use | Use with caution; consider lower starting doses due to potential hepatic impairment and increased sensitivity. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for NORLUTIN (NORLUTIN).
| Breastfeeding | Excreted in breast milk in small amounts (M/P ratio unknown). Potential for adverse effects in nursing infants (e.g., jaundice, breast enlargement). Use only if clearly needed; monitor infant for symptoms. |
| Teratogenic Risk | Pregnancy category X. First trimester: High risk of masculinization of female fetuses (labial fusion, clitoral hypertrophy) if exposure occurs between weeks 8-12. Second/third trimester: Continued risk of pseudohermaphroditism in females; possible hypospadias in males. Avoid use in pregnancy. |
■ FDA Black Box Warning
Cigarette smoking increases risk of serious cardiovascular side effects from progestin-only contraceptive use. Risk increases with age and heavy smoking (≥15 cigarettes/day). Women over 35 who smoke should not use.
| Serious Effects |
Known or suspected pregnancy, undiagnosed genital bleeding, known/suspected breast cancer, active thromboembolic disorders, history of stroke, liver disease (benign/malignant), hypersensitivity.
| Precautions | Thrombotic disorders, breast cancer risk, hepatic impairment, fluid retention, depression, elevated blood pressure, glucose intolerance, jaundice. |
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| Fetal Monitoring |
| Monitor for signs of virilization in female fetuses if exposure occurs. No specific routine monitoring required; fetal ultrasound may be considered if inadvertent exposure. |
| Fertility Effects | May inhibit ovulation and alter endometrial lining, thus reducing fertility. Reversible upon discontinuation. Not indicated for fertility enhancement. |