Head-to-head clinical analysis & difference comparison: details on mechanism of action, dosing, half-life, interactions, and maternal-fetal safety.
LUVOX vs LUVOX CR
Clinician-reviewed, head-to-head comparison of mechanism, dosing, pharmacokinetics, and safety profiles.
Last clinically reviewed: July 2026 · OpiCalc Medical Review Team
Selective serotonin reuptake inhibitor (SSRI); increases serotonergic activity by blocking reuptake of serotonin into presynaptic neurons.
Selective serotonin reuptake inhibitor (SSRI); increases serotonin availability in the synaptic cleft by blocking serotonin reuptake transporters (SERT).
Obsessive-compulsive disorder (OCD),Social anxiety disorder,Panic disorder,Premenstrual dysphoric disorder (PMDD),Bulimia nervosa,Post-traumatic stress disorder (PTSD)
Obsessive-compulsive disorder (OCD),Social anxiety disorder,Panic disorder,Post-traumatic stress disorder,Premenstrual dysphoric disorder
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.
100-300 mg orally once daily at bedtime
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.
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.
Primarily hepatic via CYP1A2; minor pathways via CYP2D6; active metabolites minimal.
Primarily hepatic via CYP2D6; undergoes extensive first-pass metabolism; major metabolites are glucuronide conjugates.
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%.
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.
Approximately 80% bound to plasma proteins, primarily albumin and alpha-1-acid glycoprotein.
Approximately 80% bound to plasma proteins, primarily albumin and alpha-1-acid glycoprotein.
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.
The apparent volume of distribution is approximately 5-9 L/kg, indicating extensive tissue distribution beyond plasma volume.
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.
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.
No dose adjustment required for mild to moderate renal impairment (Cr Cl ≥20 m L/min). Avoid use in severe renal impairment (Cr Cl <20 m L/min) due to lack of data.
No specific dose adjustment required; use caution in severe renal impairment (Cr Cl < 30 m L/min) and consider lower starting dose.
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.
Child-Pugh Class A: 50 mg/day; Class B: 25 mg/day; Class C: not recommended.
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.
Not approved for patients under 18 years.
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.
Initiate at 50 mg/day; titrate slowly to a maximum of 150 mg/day.
Increased risk of suicidal thinking and behavior in children, adolescents, and young adults with major depressive disorder and other psychiatric disorders.
Increased risk of suicidal thinking and behavior in children, adolescents, and young adults with major depressive disorder and other psychiatric disorders.
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
Serotonin syndrome,Risk of bleeding with NSAIDs/aspirin,Activation of mania/hypomania,Seizure risk,Angle-closure glaucoma risk,Sexual dysfunction,Withdrawal symptoms on discontinuation
Concomitant use with MAOIs,Concomitant use with triptans,Hypersensitivity to fluvoxamine or any excipient,Pregnancy (relative)
Concomitant use with MAOIs or within 14 days of MAOI discontinuation,Concomitant use with pimozide or thioridazine,Known hypersensitivity to fluvoxamine
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.
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.
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).
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.
Fluvoxamine is excreted into breast milk; M/P ratio ranges from 0.29 to 0.59. Relative infant dose is approximately 1.7% of maternal weight-adjusted dose. Low risk of adverse effects in breastfed infants; monitor for drowsiness, poor feeding, and weight gain. AAP classifies as compatible with 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.
Plasma levels of fluvoxamine may decrease during pregnancy due to increased volume of distribution and enhanced hepatic metabolism. Dose adjustment may be necessary; consider therapeutic drug monitoring to maintain efficacy. Usually, dose can be increased by 50-100% in third trimester, with gradual reduction postpartum to pre-pregnancy levels.
No routine dose adjustment is required for fluvoxamine during pregnancy. However, due to increased volume of distribution and enhanced hepatic metabolism (CYP1A2, CYP2D6) in pregnancy, some patients may require dose adjustments to maintain efficacy; therapeutic drug monitoring is not standard but consider checking trough levels. Initiate at lowest effective dose and titrate based on clinical response. Postpartum: Reduce dose pre-conception levels if increased during pregnancy to avoid toxicity.
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.
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.
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.
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.
"Tetracycline may inhibit the metabolism of Fluvoxamine via cytochrome P450 enzyme interference, leading to increased Fluvoxamine plasma concentrations. This elevation potentiates serotonergic effects and may precipitate serotonin syndrome, characterized by hyperthermia, autonomic instability, and neuromuscular abnormalities. Concurrent use requires careful monitoring for signs of toxicity such as agitation, confusion, and tachycardia."
"Dexlansoprazole, a proton pump inhibitor (PPI), may inhibit CYP1A2, the primary enzyme responsible for metabolizing fluvoxamine, a selective serotonin reuptake inhibitor (SSRI). This interaction can lead to increased plasma concentrations of fluvoxamine, potentiating its serotonergic effects and risk of dose-dependent adverse events such as nausea, somnolence, and serotonin syndrome. Clinicians should monitor for signs of fluvoxamine toxicity and consider dose adjustment when initiating or discontinuing dexlansoprazole."
"Afatinib, an epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor, and fluvoxamine, a selective serotonin reuptake inhibitor (SSRI), both undergo metabolism via CYP450 enzymes. Afatinib is a moderate inhibitor of CYP2D6 and may also inhibit CYP1A2 and CYP3A4, while fluvoxamine is a known inhibitor of CYP1A2 and CYP2C19. Coadministration can lead to increased fluvoxamine concentrations due to inhibition of its metabolism, potentially resulting in enhanced serotonergic effects such as serotonin syndrome, as well as increased adverse effects like nausea, dizziness, or QT prolongation."
No interactions on record
Explore head-to-head clinical comparisons of other medications in the same therapeutic classes.
Common clinical questions about LUVOX vs LUVOX CR, answered by our medical review team.
LUVOX is a SSRI Antidepressant that works by Selective serotonin reuptake inhibitor (SSRI); increases serotonergic activity by blocking reuptake of serotonin into presynaptic neurons.. LUVOX CR is a SSRI Antidepressant that works by Selective serotonin reuptake inhibitor (SSRI); increases serotonin availability in the synaptic cleft by blocking serotonin reuptake transporters (SERT).. They differ in pharmacokinetic profiles, FDA-approved indications, and side effect profiles.
Potency comparisons between LUVOX and LUVOX CR depend on the specific clinical indication. These are both SSRI Antidepressant agents and are not directly interchangeable by dose. A physician or clinical pharmacist should guide any therapeutic switching decisions.
The standard adult dose of LUVOX is: 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.. The standard adult dose of LUVOX CR is: 100-300 mg orally once daily at bedtime. Dosing should always be individualized based on indication, renal and hepatic function, age, and other patient factors.
No direct drug-drug interaction has been formally documented between LUVOX and LUVOX CR in current clinical databases. However, individual patient risk factors including other medications, organ function, and comorbidities should always be evaluated by a qualified healthcare provider.
The maternal-fetal safety profiles differ. LUVOX is classified as Category C. First trimester: Increased risk of congenital malformations, particularly cardiac defects (RR ~1.5-2) based on observational studies; also associated with persistent pulmonary hype. LUVOX CR is classified as Category C. First trimester: Epidemiologic studies have not consistently demonstrated an increased risk of major congenital anomalies; however, some studies suggest a small increased risk of c. Always consult a maternal-fetal medicine specialist before taking either drug during pregnancy or lactation.