Can Fluvoxamine Cause Neutropenia?
Fluvoxamine does not cause neutropenia in children or adolescents being treated for obsessive-compulsive disorder. There is no evidence in the medical literature linking fluvoxamine to neutropenia or other white blood cell abnormalities.
Evidence from Clinical Guidelines and Research
Safety Profile in Pediatric Populations
The American Academy of Child and Adolescent Psychiatry guidelines for anxiety disorders in children and adolescents do not list neutropenia or any hematologic adverse effects as concerns with fluvoxamine use. 1 The guideline focuses on other safety considerations including:
- Discontinuation syndrome (dizziness, fatigue, nausea, sensory disturbances) 1
- Drug-drug interactions via multiple CYP450 enzymes (CYP1A2, CYP2C19, CYP2C9, CYP3A4, CYP2D6) 1
- Initial anxiety or agitation as a potential early side effect 1
Clinical Trial Safety Data
Multiple studies in pediatric populations have documented fluvoxamine's adverse effect profile without reporting neutropenia:
An 8-week open-label trial in 20 adolescent inpatients (ages 13-18) treated with fluvoxamine 100-300 mg daily for OCD reported common side effects including dermatitis, insomnia, hyperactivity, excitement, anxiety, tremor, and nausea—but no hematologic abnormalities. 2
A placebo-controlled trial in 120 children and adolescents (ages 8-17) treated for 10 weeks showed no reports of neutropenia or blood count abnormalities. 3
Adult studies and controlled-release formulation trials similarly do not report hematologic adverse effects. 4, 5
Animal Toxicology Studies
One animal study in male rats receiving prolonged high-dose fluvoxamine (27 mg/kg) reported leukocytosis, lymphocytosis, and monocytosis—an increase in white blood cells, not a decrease. 6 This finding is opposite to neutropenia and has not been replicated in human clinical use.
Important Distinction: Clozapine vs. Fluvoxamine
Do not confuse fluvoxamine with clozapine, which does cause potentially fatal agranulocytosis:
- Clozapine (an atypical antipsychotic) causes agranulocytosis in approximately 0.4-1% of patients and requires mandatory weekly-to-monthly white blood cell monitoring. 7, 8
- Fluvoxamine (an SSRI) has no such hematologic risks and requires no routine blood count monitoring. 1, 3, 4
Clinical Implications
- No baseline or routine blood count monitoring is required when prescribing fluvoxamine for OCD in children or adolescents. 1
- Focus monitoring on clinically relevant adverse effects: gastrointestinal symptoms, activation/agitation, and discontinuation syndrome if stopping abruptly. 1, 2
- Be vigilant about drug interactions given fluvoxamine's extensive CYP450 enzyme inhibition profile. 1