Hematological ADR to Antiepileptics

• Most common antiepileptic causing neutropenia and/or agranulocytosis are : Carbamazepine (boxed warning), phenytoin, Phenobarbital, Valproate

• Other agents are such as below:

Carbamazepine	Agranulocytosis, leukopenia, thrombocytopenia, pancytopenia, leukocytosis
Phenytoin	Agranulocytosis, leukopenia, thrombocytopenia, pancytopenia, granulocytopenia
Phenobarbitone	Agranulocytosis, megaloblastic anaemia, thrombocytopenia
Valproate	Thrombocytopenia (1-24%) <1% leukopenia, pancytopenia, leukocytosis
Lamotrignine	<1%  aplastic anemia,  leukopenia, neutropenia, pancytopenia, thrombocytopenia
Levetiracetam	8% eosinophilia (4-16 years) 3% decreased WBC count <1% pancytopenia (bone marrow suppression)

Management:

• Monitor for blood dyscrasias (routine lab investigations and/or inform patient to watch for fever, sore throat, rash, etc)
• Intense monitoring for high risk patients during the first 3 months of treatment
• Frequency depends on the results of each lab values
• discontinuation of therapy is usually not indicated unless symptoms are severe, persistent, or accompanied by infection.
• Leukopenia often reverses, even if carbamazepine treatment is continued.
• A severe risk of infection exists when the patient's neutrophil count falls below 500 mm

References:

1. www.lexicomp.com
2. Careful Monitoring for Agranulocytosis During Carbamazepine Treatment. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1764526/