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. |
| Molecular Weight | 282.76 |
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 | Limited human data; animal studies show developmental toxicity. Use only if potential benefit outweighs risk. Avoid if possible. |
| 2nd trimester | May cause persistent pulmonary hypertension of the newborn (PPHN) and serotonin syndrome in neonate if used near term. Use with caution. |
| 3rd trimester | Risk of neonatal withdrawal symptoms (irritability, feeding difficulties, respiratory distress) and persistent pulmonary hypertension. Discontinue or taper before delivery if possible. |
Clinical note
Comprehensive clinical and safety monograph for MILNACIPRAN HYDROCHLORIDE (MILNACIPRAN HYDROCHLORIDE).
| Placental transfer | Crosses placenta; cord blood levels approximately 0.5-1.0 times maternal plasma levels. |
| Breastfeeding | Milk concentration is ~3 times maternal plasma levels; relative infant dose is ~3-6% of maternal weight-adjusted dose. Monitor infant for irritability, poor feeding, and sleep disturbances. Benefits may outweigh risks in maternal depression. |
■ 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 of MAOIs or within 14 days of MAOI therapyConcurrent use of linezolid or intravenous methylene blueUncontrolled narrow-angle glaucomaHypersensitivity to milnacipran or any excipient
| 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 |
| Food/Dietary | No specific food interactions, but take with food to improve gastrointestinal tolerability. Avoid alcohol. |
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| Lactation Rating | L3 (Moderately Safe) |
| 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. |
| 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. |
| Clinical Pearls | Milnacipran is a serotonin-norepinephrine reuptake inhibitor (SNRI) approved for fibromyalgia. It requires dose titration to minimize nausea, headache, and dizziness. Avoid abrupt discontinuation to prevent withdrawal symptoms. Monitor blood pressure, as it can cause sustained hypertension. Contraindicated with MAOIs and in patients with uncontrolled narrow-angle glaucoma. Use with caution in hepatic or renal impairment; adjust dose for CrCl <30 mL/min. |
| Patient Advice | Take with food to reduce nausea. Swallow capsules whole; do not crush or chew. · Avoid alcohol as it may increase dizziness and drowsiness. · It may take several weeks for full effect; do not stop suddenly without medical advice. · Report any signs of allergic reaction, worsening depression, or suicidal thoughts. · May cause dry mouth, constipation, or sweating; use hydration and fiber for relief. · Do not use with MAO inhibitors or within 14 days of stopping them. |