From the Guidelines
Quetiapine can rarely cause neutropenia, as evidenced by an unpublished report of a precipitous drop in ANC and platelets in a 12-year-old boy receiving quetiapine 1. This adverse effect is uncommon but has been documented in clinical practice, although the majority of evidence is associated with clozapine, another antipsychotic agent. The risk of neutropenia with quetiapine appears to be rare, but patients taking this medication should have baseline complete blood counts performed before starting treatment, with periodic monitoring recommended, especially for those with pre-existing low white blood cell counts or a history of drug-induced neutropenia. Some key points to consider when prescribing quetiapine include:
- Monitoring of blood counts, particularly during the first few months of treatment
- Education of patients about signs of infection, such as fever, sore throat, or flu-like symptoms, that might indicate neutropenia
- Close monitoring of blood counts until they normalize if neutropenia develops, and consideration of alternative antipsychotic medications. It is essential to weigh the benefits of quetiapine against the potential risks, including the rare but potentially serious side effect of neutropenia, as reported in the study by the American Academy of Child and Adolescent Psychiatry 1.
From the FDA Drug Label
In clinical trial and postmarketing experience, events of leukopenia/neutropenia have been reported temporally related to atypical antipsychotic agents, including quetiapine. Agranulocytosis has also been reported. Agranulocytosis (defined as absolute neutrophil count <500/mm 3) has been reported with quetiapine, including fatal cases and cases in patients without pre-existing risk factors Neutropenia should be considered in patients presenting with infection, particularly in the absence of obvious predisposing factor(s), or in patients with unexplained fever, and should be managed as clinically appropriate.
Quetiapine can cause neutropenia. Patients with a pre-existing low WBC or a history of drug-induced leukopenia/neutropenia should have their complete blood count (CBC) monitored frequently during the first few months of therapy and should discontinue quetiapine at the first sign of a decline in WBC in absence of other causative factors 2.
From the Research
Quetiapine and Neutropenia
- Quetiapine has been reported to cause neutropenia, a potentially life-threatening side effect, in several case studies 3, 4, 5, 6.
- The mechanism of quetiapine-induced neutropenia is not fully understood, but it is thought to be related to its similarity in structure to clozapine, which is known to cause blood dyscrasias 3.
- Risk factors for quetiapine-induced neutropenia may include hepatic dysfunction and concomitant fever 3.
- Patients who have developed neutropenia with previous antipsychotic agents may be at increased risk of developing it with quetiapine 5.
- Even low doses of quetiapine can cause agranulocytosis and leucopenia in patients with underlying genetic susceptibility towards low white blood cell counts 6.
Clinical Implications
- Physicians should be cautious when prescribing quetiapine, especially in patients with a history of blood dyscrasias or those taking other medications that may increase the risk of neutropenia 3, 4, 5, 6.
- Regular monitoring of white blood cell counts is recommended for patients taking quetiapine, especially during the initial stages of treatment 3, 4, 5, 6.
- If neutropenia occurs, quetiapine should be discontinued and alternative treatments considered 3, 4, 5, 6.