Recurrent Admissions for Hypothermia From Concomitant Topiramate and Phenobarbital: A Case Report

This article presents an additional case of concomitant topiramate and phenobarbital administration that resulted in 8 hospital admissions for hypothermia that resolved after discontinuation of phenobarbital. A 56-year-old white female with cerebral palsy and quadriplegia, epilepsy, and hypothyroidism was admitted to a community teaching hospital multiple times with documented hypothermia. These admissions followed a subsequent dose increase of topiramate in December 2014. In February 2015, the patient was admitted with 35°C rectal temperature. Her 2 admissions in April were for hypothermia with temperatures of 34.6°C and 33.6°C, respectively. The patient had 5 other admissions with hypothermia through December 2015. All other causes of hypothermia were ruled out. The hypothermia resolved when phenobarbital was discontinued. A recent case series noted an association between phenobarbital and topiramate causing hypothermia. The patient’s hypothermia developed while on concomitant phenobarbital and topiramate but only after an increase in topiramate. No other causes for hypothermia were found based upon physical examination or lab work. The Naranjo nomogram noted a probable causation. This case report points to an association of hypothermia with concomitant topiramate and phenobarbital with resolution after phenobarbital discontinuation. Improvement after discontinuation of phenobarbital seems to support a drug-effect relationship