Hematological effects of valproate in psychiatric patients: what are the risk factors?

Sodium valproate is an anticonvulsant that is also one of the common treatments used for bipolar disorder. The present study was conducted in psychiatric patients with the aim of examining the effects of valproate on hematological parameters and to explore any association with sex and age.

A list of all psychiatric patients who underwent valproate level estimation in the years 2004-2008 in Newcastle upon Tyne was drawn from the biochemistry database of the local hospital. The names and date of births of these patients were used to draw corresponding hematological data, including hemoglobin, white blood cell count, mean corpuscular volume (MCV), and platelet count, conducted on the same day or within a week of the valproate level measurement.

: The data from 126 patients were analyzed. The prevalence of thrombocytopenia (platelet count, <150,000/microL) was found to be approximately 5%. In female subjects, a significant negative correlation was found between serum valproate level and platelet count; also, a positive correlation between valproate level and MCV was found. Neither correlation was found in male subjects. The risk of a low platelet count was found to be significantly increased at serum valproate level above 80 microg/mL in female subjects. The regression analysis in female patients showed a trend toward fall in platelet count and an increase in MCV with increasing age.

In psychiatric patients on valproate therapy, close monitoring of full blood count is required in women particularly at valproate serum level above 80 microg/mL. This may be particularly important in older patients.