Depakote, Depakene

Renal impairment

Valproate is eliminated almost entirely (>96%) by hepatic metabolism, and renal disease has little effect on valproate metabolism.71 However, valproate is 85–95% protein bound, and renal disease significantly affects valproate protein binding.71,72 In renal disease the total valproate plasma concentration falls, principally because of decreased protein binding, but the free valproate level is unchanged. (See Effects of renal impairment on steady-state plasma concentration of drugs for further discussion of this phenomenon.) Allosteric changes in protein binding73 and endogenous toxic products displacing valproate from protein binding sites74 may also contribute to decreased protein binding.

Hemodialysis

Valproate is poorly soluble in water, is highly protein bound, and has a small volume of distribution. Less than 20% of valproate is removed by hemodialysis75 or peritoneal dialysis.76

Adapted from: Browne TR. Renal disorders. In: Ettinger AB and Devinsky O, eds. Managing epilepsy and co-existing disorders. Boston: Butterworth-Heinemann; 2002;49-62.
With permission from Elsevier (www.elsevier.com).
Reviewed and revised February 2004 by Steven C. Schachter, MD, epilepsy.com Editorial Board.