Thinking out of the box: management of valproic acid toxicity with carbapenems

Valproic acid (VPA) is commonly used medication to treat seizure disorder and as prophylaxis for bipolar disorder. Acute VPA toxicity can cause varied symptoms ranging from mild drowsiness to severe cerebral oedema and coma. The therapeutic level of VPA is around 50-100 mu g/mL and most of it is protein bound. It is mainly metabolised by liver and is eliminated via bile. The metabolites of VPA interfere with urea cycle and cause deficiency in carnitine leading to increase in ammonia levels. The use of carnitine to treat VPA toxicity is well known but it is still unclear if it lowers VPA levels. We report a case of VPA toxicity that did not respond to use of carnitine at 6000 mg orally but was successfully treated using meropenem leading to lowering of VPA levels and also clinical improvement of patient.