Valproate level

Keywords: Valproic acid, Epilim

Specimen:

5 mL blood in plain tube.

Method:

Immunoassay, HPLC.

Therapeutic Interval:

350-700 µmol/L (50-100 mg/L).

Application:

Therapeutic drug monitoring.

Interpretation:

Levels must be related to the time since previous dose.

Occasionally, hepatotoxicity may occur with serum levels < 700 µmol/L (<100 mg/L).

The half-life is about 6-20 h, but is shorter when valproate is given in combination with other anticonvulsants.

Reference:

Gugler R and von Unruh GE. Clin Pharmacokinet 1980; 5: 67-83.

Bowden CL. Bipolar Disord 2003; 5(3): 189-202.