Abstracts

Rationale: Ezogabine/retigabine (EZG) is a first-in-class potassium channel opener, with a mechanism of action different than other antiepileptic drugs. Ezogabine stabilizes in the open position the voltage-gated potassium channels (Kv7.2-Kv7.5), decreasing neuronal hyperexcitability by membrane hyperpolarization. Hallucinations and psychosis have been reported with the use of EZG in about 2% of patients in pre-marketing clinical trials. Methods: Describe a case of persistent auditory hallucinosis associated with the use of EZG.Results: A 54-year-old, right-handed male with refractory focal seizures secondary to a venous anomaly in the left anterior, infero-lateral temporal neocortex was started on EZG at a dose of 50 mg daily and increased to 50 mg tid within 3-5 days. Immediately after taking the first 50-mg dose the patient began hearing music constantly. The patient recognized the music as classic rock of which he was very fond of. Entire songs would play exactly as the original version as if listening to the radio. The music started as soon as he woke up and never stopped until he fell asleep. It would occasionally wake him up. The hallucinations could be masked if he played music in his stereo. Reducing the dose of EZG to 50 mg bid had little effect on the hallucinations. The patient elected to continue the therapy with the hallucinations continuing unabatedly. Five weeks later, due to persistence of seizures, the dose of EZG was increased to 50 mg tid with worsening of the hallucinations. The music became louder and began disrupting his sleep more severely. After 6 weeks of therapy, EZG was discontinued gradually with rapid cessation of the hallucinations as a dose of 50 mg/d was reached. Two months after the discontinuation of EZG there has been no recurrence of auditory hallucinations. Concomitant medication at the time of initiation of EZG included lamotrigine 300 mg/d and phenobarbital 30 mg/d. The latter was discontinued as the EZG was started. Patient had no history of hallucinations, psychosis or other psychiatric disease. Patient had a history of poor tolerability to multiple other antiepileptic drugs.Conclusions: the authors are unaware of prior reports of similar auditory hallucinosis consisting of well formed familiar music with EZG use.