MILNACIPRAN HYDROCHLORIDE
Clinical safety rating: caution
Comprehensive clinical and safety monograph for MILNACIPRAN HYDROCHLORIDE (MILNACIPRAN HYDROCHLORIDE).
Milnacipran is a serotonin-norepinephrine reuptake inhibitor (SNRI) with approximately 3-fold higher potency for norepinephrine reuptake inhibition compared to serotonin. It does not significantly affect dopamine or other neurotransmitter reuptake.
| Metabolism | Primarily hepatic via CYP3A4 to inactive metabolites (N-desethyl milnacipran and others). Approximately 50% excreted unchanged in urine. |
| Excretion | Primarily renal: ~60% excreted unchanged in urine; ~23% as glucuronide conjugates; ~3% as other metabolites; biliary/fecal excretion accounts for <5%. |
| Half-life | Terminal elimination half-life is approximately 6-8 hours in young adults; prolonged to 10-15 hours in elderly or patients with renal impairment (CrCl <30 mL/min). |
| Protein binding | 50-60% bound to plasma proteins, primarily albumin and alpha-1 acid glycoprotein. |
| Volume of Distribution | Approximately 5-8 L/kg, indicating extensive tissue distribution. |
| Bioavailability | Oral: ~85-90% (minimal first-pass metabolism). |
| Onset of Action | Oral: Clinical effects (antidepressant) typically begin within 1-2 weeks of therapeutic dosing; no parenteral route approved. |
| Duration of Action | Steady-state achieved within 2-3 days; once-daily dosing maintains therapeutic levels for 24 hours. Duration of effect persists as long as dosing continues; withdrawal symptoms may occur upon abrupt cessation. |
50 mg orally twice daily with food, increased to 100 mg twice daily based on tolerability and efficacy.
| Dosage form | TABLET |
| Renal impairment | For CrCl 30-59 mL/min: 50 mg daily; for CrCl 5-29 mL/min: 25 mg daily. |
| Liver impairment | Child-Pugh A: no adjustment; Child-Pugh B: reduce dose by 50%; Child-Pugh C: not recommended. |
| Pediatric use | Not FDA-approved for use in pediatric patients. |
| Geriatric use | Elderly patients may have reduced renal function; adjust dose per renal function; start at 50 mg daily. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for MILNACIPRAN HYDROCHLORIDE (MILNACIPRAN HYDROCHLORIDE).
| Breastfeeding | Milnacipran and its active metabolite are excreted into breast milk in low amounts; average infant dose is 3-5% of maternal weight-adjusted dose. Milk-to-plasma ratio is approximately 0.8. No adverse effects reported in breastfed infants; caution advised. |
| Teratogenic Risk | First trimester: Limited human data; animal studies show no teratogenicity at clinically relevant doses. Second/third trimester: Risk of neonatal adaptation syndrome (respiratory distress, feeding difficulties, jitteriness). Late third trimester: Possible persistent pulmonary hypertension of the newborn (PPHN). Overall, not a major teratogen. |
■ FDA Black Box Warning
Milnacipran is not approved for use in pediatric patients. Antidepressants increased the risk of suicidal thinking and behavior in short-term studies in children and adolescents with major depressive disorder and other psychiatric disorders.
| Serious Effects |
["Concurrent use or within 14 days of MAO inhibitors (risk of hypertensive crisis)","Uncontrolled narrow-angle glaucoma","Severe renal impairment (CrCl < 30 mL/min)"]
| Precautions | ["Serotonin syndrome risk when used with other serotonergic drugs (e.g., SSRIs, MAOIs, triptans)","Seizures: Use with caution in patients with seizure disorders","Hypertension: May increase blood pressure and heart rate; monitor regularly","Urinary hesitancy/retention: Due to norepinephrine reuptake inhibition","Hepatotoxicity: Rare cases of liver injury reported","Discontinuation syndrome: Taper dose to avoid withdrawal symptoms","Angle-closure glaucoma: May cause mydriasis; use with caution"] |
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| Fetal Monitoring | Monitor maternal blood pressure and heart rate due to noradrenaline reuptake inhibition. Assess fetal growth with ultrasound if used during second/third trimester. Observe neonate for signs of poor adaptation (e.g., irritability, feeding problems) for 48 hours postpartum if used late in pregnancy. |
| Fertility Effects | No specific studies on fertility. Based on mechanism, possible reversible effects on libido and ejaculatory function in males. In females, may affect menstrual cycle; no known impact on conception. |