Tardive dystonia induced by low-dose gabapentin in a severely disabled patient with epilepsy

Background

Gabapentin-related dystonia is rare, occurring mainly at high doses. We herein report a rare case of dystonia induced by low-dose gabapentin.

Case presentation

A severely disabled patient was treated for epilepsy with valproate, lamotrigine, and phenytoin. He developed myocarditis at 25 years old, and severe bradycardia was noted 4 years later. Phenytoin was discontinued as it causes bradycardia, which subsequently resolved, and zonisamide was introduced. Seven months later, the patient developed orolingual dyskinesia. Zonisamide was gradually discontinued, and the dyskinesia subsided. He was prescribed gabapentin 100 mg 3 times daily. After 14 months of gabapentin treatment, the patient developed repetitive rotational movements in the torso and right arm. The patient also exhibited laryngeal dystonia and Pisa syndrome. After discontinuation of gabapentin, the movement disorders resolved.

Conclusions

In this case, low-dose gabapentin prescription led to dystonia in various parts of the body, including the larynx, as a life-threatening complication. When patients with epilepsy exhibit involuntary movements, the adverse effects of anti-seizure medications should be considered.