Discussion: The basal ganglia perform a neuroregulatory function between the motor cortex and the thalamus. This role involves both positive and negative synaptic pathways. Choreoathetoid movement may result when the inhibitory functions of the basal ganglia are suppressed. Gabapentin increases brain levels of gamma-aminobutyric acid (GABA), a primary inhibitory neurotransmitter. The most common neurological signs of gabapentin toxicity are altered mental status, tremor, and ataxia. Myoclonus occurs, but is uncommon, and chorea has only rarely been reported. Predisposing factors to gabapentin neurotoxicity include advanced age, renal insufficiency, and ischemic cerebrovascular disease.
Conclusions: Declining renal function in the elderly patient taking gabapentin is a major risk factor for the development of gabapentin neurotoxicity, particularly in the setting of pre-existing cerebral ischemic change. Patients receiving relatively high doses of gabapentin may be particularly prone to adverse effects. Although gabapentin toxicity is typically manifest by either subtle mental status change or gait abnormalities, it may on rare occasions present with severe movement disorders such as mycoclonus or chorea. Heightened awareness of risk factors, and of the spectrum of gabapentin toxicity, may assist with prompt recognition and resolution.
To cite this abstract:VanHook, CJ; Laredo, R; Beer, M; Tangel, D . GABAPENTIN TOXICITY PRESENTING AS CHOREOATHETOSIS. Abstract published at Hospital Medicine 2017, May 1-4, 2017; Las Vegas, Nev. Abstract 769. Journal of Hospital Medicine. 2017; 12 (suppl 2). https://www.shmabstracts.com/abstract/gabapentin-toxicity-presenting-as-choreoathetosis/. Accessed February 21, 2020.