LUVOX CR
Clinical safety rating
cautionComprehensive clinical and safety monograph for LUVOX CR (LUVOX CR).
Selective serotonin reuptake inhibitor (SSRI); increases serotonin availability in the synaptic cleft by blocking serotonin reuptake transporters (SERT).
| Metabolism | Primarily hepatic via CYP2D6; undergoes extensive first-pass metabolism; major metabolites are glucuronide conjugates. |
| Excretion | Approximately 94% of a dose is excreted in urine, with less than 4% as unchanged drug. The remainder is eliminated in feces. Renal excretion of metabolites accounts for the majority of elimination. |
| Half-life | The terminal elimination half-life is approximately 15-20 hours after single doses and 17-26 hours after multiple doses. This supports once-daily dosing, with steady-state achieved within 1-2 weeks. |
| Protein binding | Approximately 80% bound to plasma proteins, primarily albumin and alpha-1-acid glycoprotein. |
| Volume of Distribution | The apparent volume of distribution is approximately 5-9 L/kg, indicating extensive tissue distribution beyond plasma volume. |
| Bioavailability | Oral bioavailability is approximately 50-70% due to first-pass metabolism. Administration with food may slightly delay absorption but does not significantly alter the extent of absorption. |
| Onset of Action | Therapeutic effects in obsessive-compulsive disorder may begin after 2-4 weeks of daily dosing, with full benefit often requiring 8-12 weeks. No immediate effect is observed after a single dose. |
| Duration of Action | The duration of action extends beyond 24 hours due to the long half-life, allowing once-daily administration. Continuous dosing is required to maintain therapeutic plasma levels. |
| Molecular Weight | 434.5 |
100-300 mg orally once daily at bedtime
| Dosage form | CAPSULE, EXTENDED RELEASE |
| Renal impairment | No specific dose adjustment required; use caution in severe renal impairment (CrCl < 30 mL/min) and consider lower starting dose. |
| Liver impairment | Child-Pugh Class A: 50 mg/day; Class B: 25 mg/day; Class C: not recommended. |
| Pediatric use | Not approved for patients under 18 years. |
| Geriatric use | Initiate at 50 mg/day; titrate slowly to a maximum of 150 mg/day. |
| 1st trimester | Limited data; risk of major malformations unclear, but some studies suggest possible increased risk of cardiac defects. Use only if clearly needed. |
| 2nd trimester | No specific risks identified; however, use with caution and monitor for maternal side effects. |
| 3rd trimester | Risk of persistent pulmonary hypertension of the newborn (PPHN) and neonatal adaptation syndrome (irritability, feeding difficulties, respiratory distress). Consider gradual taper before delivery if possible. |
Clinical note
Comprehensive clinical and safety monograph for LUVOX CR (LUVOX CR).
| Placental transfer | Fluvoxamine crosses the placenta. Cord blood concentrations are approximately 50-70% of maternal serum concentrations, indicating moderate placental transfer. |
| Breastfeeding | Fluvoxamine is excreted into human breast milk in low concentrations. Relative infant dose is approximately 1-2% of maternal weight-adjusted dose. Monitor infant for drowsiness, poor feeding, and adequate weight gain. Use with caution, especially in preterm infants or those with compromised hepatic function. |
| Lactation Rating | L2 (Safer) |
| Teratogenic Risk | First trimester: Epidemiologic studies have not consistently demonstrated an increased risk of major congenital anomalies; however, some studies suggest a small increased risk of cardiovascular malformations (e.g., ventricular septal defect) with maternal use of SSRIs overall. Fluvoxamine has limited data but is considered low risk. Second and third trimesters: Late pregnancy exposure may be associated with persistent pulmonary hypertension of the newborn (PPHN) (absolute risk about 1-2 per 1000), preterm birth, and transient neonatal adaptation syndrome (irritability, tachypnea, poor feeding) requiring monitoring. Neonatal withdrawal syndrome (serotonin discontinuation syndrome) may occur. |
| Fetal Monitoring | Maternal: Assessment of mood stability, suicide risk, and side effects (nausea, insomnia, sexual dysfunction). Fetal/neonatal: Third-trimester ultrasound for fetal growth; neonatal monitoring for signs of poor adaptation (respiratory distress, temperature instability, feeding difficulty) and serotonin discontinuation syndrome (especially if used near term). |
| Fertility Effects | Fluvoxamine may cause reversible sexual dysfunction (delayed ejaculation, anorgasmia) in males and females. Data on direct impact on fertility are limited; in animal studies, no significant impairment of fertility was observed. In humans, SSRIs are not associated with reduced fertility, but sexual side effects may affect reproductive behavior. |
■ 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 |
Concurrent use with MAOIs (or within 14 days of discontinuation)Concurrent use with thioridazineConcurrent use with pimozideConcurrent use with alosetronHypersensitivity to fluvoxamine maleate or any component of the formulation
| Precautions | Serotonin syndrome, Risk of bleeding with NSAIDs/aspirin, Activation of mania/hypomania, Seizure risk, Angle-closure glaucoma risk, Sexual dysfunction, Withdrawal symptoms on discontinuation |
| Food/Dietary | No specific dietary restrictions. Grapefruit and grapefruit juice may increase fluvoxamine levels; avoid large quantities. Limit caffeine intake, as fluvoxamine may decrease caffeine clearance and increase stimulant effects. |
| Clinical Pearls | LUVOX CR is an extended-release formulation of fluvoxamine, an SSRI approved for OCD. Dosing: start 100 mg at bedtime, titrate by 50 mg weekly up to 300 mg. Avoid abrupt discontinuation due to withdrawal symptoms. Monitor for serotonin syndrome, especially with concomitant serotonergic drugs. CR tablets must be swallowed whole; do not crush or chew. |
| Patient Advice | Take LUVOX CR once daily at bedtime to minimize daytime sedation. · Swallow the tablet whole; do not crush, chew, or cut it. · May take 2-4 weeks for therapeutic effect; consistent adherence is important. · Do not stop taking abruptly; consult your doctor before discontinuing. · Avoid alcohol, as it may increase drowsiness and risk of adverse effects. · Report any suicidal thoughts, unusual mood changes, or serotonin syndrome symptoms (e.g., agitation, hallucinations, fever, rapid heart rate). · Use caution when driving or operating machinery until you know how LUVOX affects you. |
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