LUVOX CR
Clinical safety rating: caution
Comprehensive 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. |
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 | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for LUVOX CR (LUVOX CR).
| Breastfeeding | Fluvoxamine is excreted into breast milk with an M/P ratio of approximately 0.29. Relative infant dose is estimated at 1.5-2% of maternal weight-adjusted dose. Cases of adverse effects in breastfed infants (e.g., irritability, poor feeding, sedation) are rare. Breastfeeding is generally considered acceptable with monitoring for infant neurobehavioral changes. |
| 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. |
■ 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 discontinuation","Concomitant use with pimozide or thioridazine","Known hypersensitivity to fluvoxamine"]
| 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"] |
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| 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. |