Voxamin

Approved indications (typical, adults & children as labelled in major jurisdictions):

• Obsessive–compulsive disorder (OCD): First-line pharmacotherapy for OCD in adults and pediatric patients (commonly approved for children/adolescents in many regions).
• Major depressive disorder (MDD): Used for treatment of depressive episodes in adults in many countries (in some regions depression is an on-label indication; in others fluvoxamine is used off-label for depression).
• Social anxiety disorder / social phobia: Approved in some countries; used clinically where indicated.
• Panic disorder: Used in clinical practice; regulatory approval varies by country.

Common clinically accepted (off-label) / adjunct uses:

• Post-traumatic stress disorder (PTSD) (selected cases).
• Other anxiety spectrum disorders when SSRIs are appropriate and clinician judgment supports use.

Note: Local labeling differs by country — always follow local regulatory labeling and specialist guidance for pediatric use and specific indications.

General principles

• Start low and titrate to effect while monitoring tolerability and interactions. Evening dosing is common for immediate-release formulations because of initial sedation for some patients, though twice-daily schedules may be used to reduce GI side effects.
• Reassess clinical response and tolerability after 4–12 weeks at an effective dose before declaring lack of efficacy.

Adult dosing (typical, immediate-release and extended-release where available)

• Initial (IR): 50 mg once daily (often at bedtime).
• Titration: Increase in 50 mg increments every 4–7 days as needed and tolerated.
• Typical effective range: 100–200 mg/day (divided doses or once daily depending on formulation).
• Higher doses: Up to 300 mg/day may be used for resistant OCD under specialist supervision (monitoring for adverse effects and interactions).
• Extended-release (ER) formulations (where available): commonly start 100 mg once daily and may be titrated to 300 mg once daily depending on local product labeling.

Pediatric dosing (OCD; typical guidance)

• Children/adolescents (approx. 8–17 years): Start lower, e.g., 25–50 mg/day, titrate gradually. Common effective ranges 50–200 mg/day, individualized by age, weight and tolerability. Specialist (child/adolescent psychiatrist) supervision required. Safety not established in very young children.

Elderly

• Initiate at lower doses (e.g., 25–50 mg/day) and titrate slowly. Monitor for hyponatremia, sedation, orthostasis, and drug interactions.

Renal impairment

• No specific routine dose adjustment required in mild–moderate renal impairment, but use caution in severe impairment and monitor for accumulation and adverse effects. Individualize dosing.

Hepatic impairment

• Because fluvoxamine is extensively metabolized in the liver, use caution and consider lower initial doses and slower titration in moderate hepatic impairment; avoid or use with extreme caution in severe hepatic dysfunction. Monitor LFTs and clinical status.

Switching / discontinuation

• When stopping, taper gradually (typically over 2 weeks or longer) to reduce risk of discontinuation symptoms (dizziness, irritability, insomnia, sensory disturbances, flu-like symptoms). If switching from or to MAO inhibitors follow recommended washout intervals (see section 7 & 10).

Administration notes

• Oral tablets or capsules; take with or without food.
• Take at the same time each day; if dose split, morning and evening spacing may reduce nausea.
• Advise patients not to abruptly stop therapy without clinician approval.

Fluvoxamine is a selective serotonin reuptake inhibitor (SSRI). It binds with high affinity to the presynaptic serotonin transporter (SERT), inhibiting reuptake of serotonin (5-HT) into the presynaptic neuron and thereby increasing synaptic 5-HT concentrations. This modulation of serotonergic neurotransmission reduces obsessive thoughts and compulsive behaviors in OCD and relieves anxiety and depressive symptoms in susceptible patients. Fluvoxamine also has notable activity at the sigma-1 receptor, which may contribute to some of its clinical and neuroprotective effects. The downstream clinical benefits evolve over weeks as neuronal networks adapt.

• Absorption: Well absorbed orally. Tmax typically occurs within a few hours (formulation-dependent). Food can slow absorption but does not meaningfully reduce overall exposure.
• Bioavailability: Moderate due to first-pass metabolism.
• Distribution: Widely distributed and highly protein-bound.
• Metabolism: Extensively metabolized in the liver (multiple CYP isoenzymes involved). Fluvoxamine is both a substrate and a potent inhibitor of several CYP enzymes (notably CYP1A2 and CYP2C19) and interacts with others (see section 10).
• Half-life: Elimination half-life is in the range that supports once- or twice-daily dosing (commonly reported ~12–20 hours in adults; variability occurs with age, dose, and hepatic function).
• Elimination: Metabolites are excreted primarily in urine; some biliary/fecal elimination of metabolites occurs.
• Steady state: Reached in several days; clinical effects require longer (weeks).

Practical point: individual pharmacokinetics vary with age, hepatic function, and co-medications—monitor clinically and adjust dosing when necessary.

• Pregnancy: There are limited and mixed human data. Historically SSRIs were classed as FDA Category C; blanket contraindications have been relaxed for many drugs, but fluvastamine should generally be discontinued when pregnancy is recognized unless the prescribing clinician, together with the patient, judges that the benefits outweigh potential fetal risks (e.g., severe refractory maternal illness). Consider specialist (perinatal psychiatry) input for treatment decisions. Possible risks with late-pregnancy SSRI exposure include neonatal adaptation syndrome; absolute risks are small but require counseling.
• Lactation: Fluvoxamine is excreted into breast milk. Because of potential infant exposure, breastfeeding is generally approached cautiously: choose to withhold breastfeeding, temporarily stop the drug, or continue while monitoring the infant for sedation, poor feeding or other adverse effects — decisions should be individualized with specialist input.

• Primary class: Antidepressant / anxiolytic — Selective Serotonin Reuptake Inhibitor (SSRI).

Notable pharmacologic features: High SERT selectivity and clinically significant CYP enzyme inhibition profile; sigma-1 receptor agonism is a distinctive pharmacologic property.

• Known hypersensitivity to fluvoxamine or any component of the formulation.
• Concomitant use of monoamine oxidase inhibitors (MAOIs) (risk of life-threatening serotonin syndrome). Avoid starting fluvoxamine within 14 days of stopping an MAOI and do not start an MAOI within 14 days of stopping fluvoxamine (or follow the specific, longer washout recommended for fluvoxamine due to its enzyme effects and duration).
• Concomitant use with tizanidine: Contraindicated — fluvoxamine markedly increases tizanidine concentrations causing severe hypotension and sedation.
• Concomitant use with pimozide: Generally contraindicated because of risk of QT prolongation and elevated pimozide levels.
• Severe hepatic impairment (use is generally contraindicated or requires specialist oversight).

• Serotonin syndrome: Potentially life-threatening — especially when combined with other serotonergic drugs (e.g., other SSRIs, SNRIs, MAOIs, triptans, tramadol, linezolid, certain recreational drugs). Watch for agitation, hyperthermia, autonomic instability, neuromuscular abnormalities; stop serotonergic agents and seek urgent care if suspected.
• Suicidal thoughts & behaviors: Antidepressants (including SSRIs) increase risk of suicidal ideation and behavior in children, adolescents and young adults (up to ~24 years). Monitor closely during initiation and dose changes.
• Hyponatremia / SIADH: Particularly in elderly or volume-depleted patients; monitor sodium if symptomatic.
• Bleeding risk: SSRIs may increase bleeding tendency (especially with NSAIDs, antiplatelets, anticoagulants). Use caution and monitor.
• Mania / bipolar disorder: May precipitate mania or hypomania in patients with bipolar disorder — screen prior to initiation.
• Seizure risk: Use cautiously in patients with seizure disorders; high doses or interactions raising plasma levels increase risk.
• Discontinuation symptoms: Abrupt cessation can cause dizziness, sensory disturbances, sleep disturbance, agitation and flu-like symptoms; taper gradually.
• Drug–drug interactions: Because fluvoxamine strongly inhibits several CYP enzymes, it can raise levels of many concomitant drugs — review full medication list before prescribing (see section 10).
• Cardiac: Use caution with drugs that prolong QT interval; although fluvoxamine itself is not a major QT-prolonger, interactions increasing substrate levels can increase risk.

Very common / common

• Gastrointestinal: Nausea (often early), vomiting, diarrhea, constipation.
• CNS: Somnolence or sedation, insomnia, headache, dizziness, nervousness, anxiety.
• Sexual dysfunction: Reduced libido, delayed ejaculation, anorgasmia.
• Sweating, tremor, dry mouth.

Less common / serious

• Hyponatremia (SIADH), especially in older adults.
• Bleeding/bruising: when combined with anticoagulants/antiplatelets/NSAIDs.
• Manic switch in bipolar patients.
• Seizures at high doses or with interacting drugs.
• Severe allergic reactions (rare).
• Discontinuation syndrome on abrupt stop.

Onset & dose dependence

• GI and CNS side effects commonly appear early (days–weeks) and often improve with continued treatment. Sexual side effects and weight changes may appear later and can be persistent. Risk/severity of some effects increases with higher doses or with interacting drugs that raise fluvoxamine exposure.

Fluvoxamine has a clinically important interaction profile due to inhibition of multiple CYP enzymes and effects on drug transport:

Major interactions (clinically important — avoid or adjust):

• MAO inhibitors — risk of serotonin syndrome (contraindicated).
• Tizanidine — contraindicated (severe hypotension, sedation).
• Pimozide — generally contraindicated (risk of QT prolongation).
• Tricyclic antidepressants, certain antipsychotics, benzodiazepines, opioids (e.g., tramadol), and many others — fluvoxamine increases concentrations via CYP inhibition; monitor and reduce doses as required.
• Warfarin — can increase INR; monitor INR when initiating or stopping fluvoxamine.
• Theophylline, caffeine, clozapine, olanzapine, carbamazepine, diazepam (and other CYP1A2/2C19 substrates): levels can be increased; dose adjustments or monitoring required.
• SSRIs/SNRIs/triptans/linezolid/MAOIs/other serotonergic agents — increased risk of serotonin syndrome; use caution, avoid combinations where possible.
• Cholesterol medications (statins): some statins metabolized by CYP2C19/3A4 may have increased levels — monitor for myopathy.
• Colchicine and other myotoxic agents: risk of toxicity if levels rise.
• Alcohol: may exacerbate CNS depression and impair judgment — advise caution.

Mechanism notes

• Fluvoxamine is a potent inhibitor of CYP1A2 and CYP2C19, and it also inhibits CYP2D6 and CYP3A4 to varying degrees — this produces multiple clinically important interactions. Always review concomitant medications for CYP substrates and adjust dosing or choose alternatives.

• Suicide monitoring: Contemporary guidelines reiterate the need to monitor young patients closely for suicidal ideation during antidepressant initiation.
• Perinatal use: Current practice stresses individualized decision-making for continuing SSRIs during pregnancy/lactation, involving risks of untreated maternal illness vs fetal/infant exposure; consultation with perinatal psychiatry is recommended for complex cases.
• Drug-interaction awareness: Guidance increasingly highlights the importance of CYP interaction screening before prescription because fluvoxamine’s inhibitory profile can cause serious adverse interactions with commonly used drugs (e.g., antipsychotics, anticoagulants, certain analgesics).
• COVID-19 note: Early in the COVID-19 pandemic fluvoxamine was studied in trials for potential antiviral/anti-inflammatory benefit; however, such uses are experimental and not standard, and decisions should follow up-to-date regulatory guidance and trial results.

• Store at room temperature: typically 20–25°C (68–77°F); short excursions allowed per product labeling (e.g., 15–30°C).
• Protect from moisture and light.
• Keep tablets/capsules in original container, tightly closed.
• Keep out of reach of children.