LUVOX
Clinical safety rating
cautionComprehensive clinical and safety monograph for LUVOX (LUVOX).
Selective serotonin reuptake inhibitor (SSRI); increases serotonergic activity by blocking reuptake of serotonin into presynaptic neurons.
| Metabolism | Primarily hepatic via CYP1A2; minor pathways via CYP2D6; active metabolites minimal. |
| Excretion | Approximately 94% of a dose is excreted in urine, mostly as conjugated and oxidized metabolites, with 2% as unchanged drug. Fecal excretion accounts for less than 4%. |
| Half-life | The terminal elimination half-life is approximately 15-20 hours but may be prolonged in patients with hepatic impairment or with advanced age. Steady-state is typically achieved within 7-10 days of chronic dosing. |
| Protein binding | Approximately 80% bound to plasma proteins, primarily albumin and alpha-1-acid glycoprotein. |
| Volume of Distribution | The apparent volume of distribution is about 4.7 L/kg, indicating extensive extravascular distribution and tissue binding, which contributes to its long half-life. |
| Bioavailability | Oral bioavailability is approximately 53% after a single dose, with no significant food effect. Bioavailability may be higher under steady-state conditions due to saturation of first-pass metabolism. |
| Onset of Action | Oral: Clinical improvement in obsessive-compulsive disorder (OCD) may begin within 2 weeks but full therapeutic effect often requires 4-6 weeks or longer. |
| Duration of Action | Due to its half-life, therapeutic effects persist for approximately 24 hours with once-daily dosing. Steady-state concentrations are maintained with regular administration. |
| Molecular Weight | 318.34 |
Initial dose 50 mg orally once daily at bedtime, titrated by 50 mg increments every 4-7 days to effective dose; usual therapeutic range 100-300 mg/day divided once daily (at bedtime) or twice daily if tolerated. Maximum dose 300 mg/day.
| Dosage form | TABLET |
| Renal impairment | No dose adjustment required for mild to moderate renal impairment (CrCl ≥20 mL/min). Avoid use in severe renal impairment (CrCl <20 mL/min) due to lack of data. |
| Liver impairment | Child-Pugh Class A: no dose adjustment; Child-Pugh Class B: reduce dose by 50% (start 25 mg/day, titrate cautiously); Child-Pugh Class C: contraindicated. |
| Pediatric use | Children (8-17 years): start 25 mg orally once daily at bedtime; increase by 25 mg increments every 4-7 days to target dose; for OCD: 25-200 mg/day; maximum 200 mg/day. Weight not routinely used; dosing based on age and response. |
| Geriatric use | Start 25 mg orally once daily at bedtime; titrate slowly (increases of 25 mg every 1-2 weeks); usual maximum 200 mg/day due to increased sensitivity and risk of hyponatremia. |
| 1st trimester | Limited human data; animal studies show no teratogenicity at clinically relevant doses. Use only if potential benefit justifies potential risk. |
| 2nd trimester | Limited human data; no evidence of increased risk of major malformations. Monitor for fetal growth. |
| 3rd trimester | Risk of persistent pulmonary hypertension of the newborn (PPHN) and neonatal adaptation syndrome (irritability, feeding difficulties) with late exposure. |
Clinical note
Comprehensive clinical and safety monograph for LUVOX (LUVOX).
| Placental transfer | Fluvoxamine crosses the placenta; cord blood concentrations approximate 50-70% of maternal plasma levels. |
| Breastfeeding | Fluvoxamine is excreted into breast milk in low amounts (relative infant dose approximately 1-2%). Monitor infant for irritability, poor feeding, and sedation. Benefits of breastfeeding likely outweigh low risk. |
| Lactation Rating | L2 (Probably Compatible) |
| Teratogenic Risk | First trimester: Increased risk of congenital malformations, particularly cardiac defects (RR ~1.5-2) based on observational studies; also associated with persistent pulmonary hypertension of the newborn (PPHN) (OR 2.1). Second/third trimester: Late pregnancy exposure may increase risk of preterm birth, low birth weight, and neonatal adaptation syndrome (e.g., respiratory distress, feeding difficulties, irritability). |
| Fetal Monitoring | Maternal: Baseline and periodic liver function tests due to risk of hepatotoxicity; thyroid function if hyperthyroidism symptoms; weight gain and nutritional status. Fetal: Standard ultrasound for anatomy and growth; consider fetal echocardiography if first-trimester exposure. Neonatal: Observe for adaptation syndrome for 48-72 hours after delivery. |
| Fertility Effects | Available data do not indicate significant adverse effects on fertility in humans. In animal studies, no impairment of fertility observed at clinically relevant doses. May cause sexual dysfunction (e.g., delayed ejaculation) which can reversibly affect conception. |
■ FDA Black Box Warning
Increased risk of suicidal thinking and behavior in children, adolescents, and young adults with major depressive disorder and other psychiatric disorders.
| Serious Effects |
Concomitant use with MAOIs or within 14 days of MAOI discontinuationConcomitant use with pimozideConcomitant use with thioridazineKnown hypersensitivity to fluvoxamine
| Precautions | Suicidality risk in young patients, Serotonin syndrome, Activation of mania/hypomania, Seizure risk, Abnormal bleeding, Angle-closure glaucoma, Hyponatremia, QT prolongation, Sexual dysfunction, Discontinuation syndrome |
| Food/Dietary | Avoid grapefruit juice as it inhibits CYP1A2 and can increase fluvoxamine serum concentrations, leading to toxicity. No other significant food interactions; however, taking with food may reduce GI upset. |
| Clinical Pearls | Luvox (fluvoxamine) is a selective serotonin reuptake inhibitor (SSRI) approved for obsessive-compulsive disorder (OCD) and social anxiety disorder. It has a short half-life (15-22 hours) and no active metabolites, making it suitable for patients with hepatic impairment. Monitor for serotonin syndrome, especially when co-prescribed with other serotonergic agents. Luvox is a potent inhibitor of CYP1A2, affecting metabolism of drugs like clozapine, olanzapine, theophylline, and tizanidine. Titrate slowly; start at 50 mg nightly and increase by 50 mg every 4-7 days to a max of 300 mg daily (divided for doses >100 mg). Discontinuation syndrome is common; taper gradually. |
| Patient Advice | Take Luvox exactly as prescribed, usually once daily at bedtime to minimize daytime drowsiness. · It may take several weeks to feel the full effect; do not stop abruptly without consulting your doctor. · Avoid grapefruit juice, which can increase Luvox levels and side effects. · Report any signs of serotonin syndrome (hallucinations, agitation, rapid heart rate, fever, muscle stiffness) immediately. · Do not drive or operate heavy machinery until you know how Luvox affects you, as it can cause drowsiness or dizziness. · Limit alcohol consumption; alcohol can worsen sedation and increase risk of side effects. · Store at room temperature, away from moisture and heat. |
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