Transient leucopenia, thrombocytopenia and anaemia associated with severe acute phenobarbital intoxication in a dog

A nine-year-old Labrador retriever dog was admitted to the emergency unit of the Hebrew University Veterinary Teaching Hospital with acute-onset tremors and coma. It had recently ingested a large quantity of phenobarbital and had a high serum phenobarbital concentration. On this basis, a diagnosis of acute phenobarbital intoxication was made. Significant leucopenia, thrombocytopenia and mild anaemia developed on the third day after admission. The leucopenia resolved on day 6 and the thrombocytopenia on day 13. The red blood cell count remained low for the next month. The dog was discharged on day 13 at which time it was ambulatory but weak. It was completely recovered clinically eight days later. In summary, high levels of serum phenobarbital as a result of acute intoxication induced pancytopenia, which improved when the serum phenobarbital level was normalised.