Meropenem as an antidote for intentional valproic acid overdose

Valproic acid (VPA) is a broad-spectrum antiepileptic drug indicated for monotherapy and adjunctive therapy of seizures, and complex manic episodes associated with bipolar disorder [1]. While uncommon due to monitoring, VPA can cause toxicity at supratherapeutic levels [1, 2]. Traditional treatment for VPA toxicity is primarily supportive care, however activated charcoal, l-carnitine, and hemodialysis have been successful in removing free VPA [2]. An interaction between carbapenem antibiotics and VPA is well-established and listed in respective package inserts as a combination to be avoided due to decreased VPA efficacy [1, 3]. Recent literature suggests co-administration of meropenem with VPA reduces mean plasma VPA levels by 50-80% [4, 6]. This case report describes the successful use of carbapenems to intentionally lower toxic VPA levels in a 42 year old female that presented to the emergency department with VPA toxicity from an overdose with divalproex sodium.