Valproate - serum

Last updated: Tuesday, 30, March, 2004

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Item Process
Specimen

5 mL blood in plain tube.

Method

Immunoassay, chromatography.

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 hours, 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.