Neutropenia and thrombocytopenia in three dogs treated with anticonvulsants.

Three dogs became lethargic and had poor appetites within 2 months after anticonvulsant treatment was initiated to control seizures. Dogs were neutropenic, thrombocytopenic, and anemic and had splenomegaly. Sensitivity to phenobarbital and related anticonvulsants may induce life-threatening leukopenia, thrombocytopenia, and anemia in dogs. Phenobarbital-induced neutropenia in these 3 dogs may have posed a risk for developing bacteremia. It is important for clinicians to be aware of adverse effects so that adequate precautions can be taken. A baseline hemogram should always be obtained before starting anticonvulsant treatment, and periodic hemograms should be obtained to monitor animals. Furthermore, client education should include instructions on recognizing signs of bacteremia, thrombocytopenia, and anemia.