[Chlorpromazine-induced agranulocytosis: a case report]

Area of Science:

• Pharmacology
• Hematology
• Psychiatry

Background:

• Drug-induced agranulocytosis is a rare but serious adverse effect of medications.
• Phenothiazines, including chlorpromazine, are known to potentially cause agranulocytosis through various mechanisms.
• Risk factors such as old age and concurrent use of other medications can increase susceptibility.

Observation:

• A 50-year-old male on chlorpromazine for schizophrenia developed agranulocytosis (leukocytes 1.4G/L, neutrophils 0.2G/L) two months after treatment initiation.
• The patient had prior exposure to phenothiazines without adverse effects.
• Blood counts normalized after chlorpromazine discontinuation, confirming the drug's role.

Findings:

• Chlorpromazine was identified as the cause of toxic agranulocytosis in this patient.
• The occurrence was temporally linked to chlorpromazine introduction and resolved upon cessation.
• Risk factors identified included old age, polypharmacy, and previous high-dose phenothiazine exposure.

Implications:

• The risk of chlorpromazine-induced agranulocytosis may be underestimated compared to other antipsychotics like clozapine.
• Pre-treatment blood counts are recommended for patients with risk factors before initiating phenothiazine therapy.
• Awareness and monitoring are crucial for managing potential severe adverse drug reactions in psychiatric patients.