Side Effect Profile of Enteric-Coated Divalproex Sodium Versus Valproic Acid

Letter to the Editor

Sir: Valproic acid and its derivatives are important agents in the treatment of patients with bipolar illness. This drug has been extensively researched in the treatment of epilepsy, where 2 of its common side effects have included gastrointestinal side effects and thrombocytopenia. Two representative derivatives are valproic acid and divalproex sodium (the enteric-coated derivative), the latter being more expensive but equally effective. However, in individual clinical cases, the side effect profile and tolerability of each of these derivatives also need to be taken into consideration. We present here a case report of a naturalistic A-B-A design, which included the replacement of divalproex by valproic acid that resulted in the occurrence of gastrointestinal symptoms and thrombocytopenia, while a switch back to divalproex resulted in the disappearance of these adverse effects.