Disabling tremor induced by long-term use of sodium valproate and lamotrigine: Case report

Sodium valproate (VPA) and lamotrigine (LTG) are widely used antiepileptic drugs, disabling postural, and action tremors after using LTG with VPA were reported in 1993. However, in this study, we describe a patient in whom disabling resting-type tremor induced by 2-year use of VPA and LTG.

A 50-year old man was referred to department of neurology because of involuntary upper limbs resting-type tremor with high amplitude that had begun 6 months previously and progressively worsened, and he could not work on the day of visit. Furthermore, he had been treated with VPA, LTG, and benzhexol for 2 years as he suffered from twitch of eyelids and facial region, and amantadine, monolithic compound preparation (flupentixol and melitracen) were added in the last 2 months because of tremor and anxiety. However, the treatment had no benefit on improving involuntary movements of the patient.

Drug-induced disabling tremor was diagnosed.

LTG, amantadine, and VPA were withdrawn, the remaining 2 drugs, benzhexol and compound preparation (flupentixol and melitracen), were continued to use, and the patient improved in 2.5 months after discontinuation of 3 drugs. There was no recurrence at 6 months follow-up.

Considering the wide and long-term utilization of VPA and LTG, healthcare providers should be aware of them as a possible cause of tremor. When necessary, an attempt of discontinuing the suspected drugs should be made to confirm the diagnosis, instead of symptomatic treatment, especially when the adverse event was severe and fatal.