Topiramate Overdose: Clinical and Laboratory Features.

Limited data exist on overdose with new antiepileptic drugs. We reviewed the medical records of two patients who took a topiramate overdose as a suicide attempt. We recorded their medical and seizure histories, concomitant antiepileptic medications, neurologic examination, and laboratory findings at the time of presentation following the overdose. We also recorded their progress and the evolution of laboratory abnormalities. Both patients progressed to coma and had generalized convulsive status epilepticus, requiring intubation and treatment with benzodiazepines. Both patients recovered within 2 days but had a non-anion-gap metabolic acidosis that persisted for 5-6 days. Physicians should carefully monitor patients treated with topiramate who develop signs of clinical depression. The non-anion-gap metabolic acidosis observed may be due to inhibition of renal cortical carbonic anhydrase.