2019 Volume 31 Issue 2 Pages 207-215
[Introduction] Development of alternative medicines other than antipsychotics to treat delirium in Parkinson’s disease (PD) is imperative. Some reports suggest that gabapentin might be able to suppress delirium. Here, we report cases of PD with delirium that were effectively and we safely improved with gabapentin without exacerbation of extrapyramidal symptoms, and we discuss the potential of gabapentin as an alternative to antipsychotics. [Case 1] An 82-year-old PD patient with pneumonia presented with delirium accompanied by impairment of sleep-wake cycle, attention and short-term memory. Gabapentin 100 mg nocte improved sleep-wake cycle disturbance initially, and most symptoms were alleviated faster than the pneumonia. Parkinsonism did not deteriorate. [Case 2] A 66-year-old PD patient with cerebellar infarction developed delirium. Perceptual disturbance, delusion, labile affect, and impairment of attention, short-term memory, and visuospatial ability were observed. Gabapentin 100 mg nocte improved cognitive function and affect initially. Hallucination and delusion diminished after gabapentin was increased to 200 mg/day. Parkinsonism was not aggravated. [Discussion] Our study highlights two important findings. Firstly, gabapentin assuaged delirium without exacerbation of symptoms of PD, suggesting that gabapentin is a likely alternative to antipsychotics for treatment of delirium in PD patients. Secondly, gabapentin, which affects the γ-aminobutyric acid (GABA)/glutamate system, seems to improve delirium by a different mechanism in comparison to the administration of antipsychotics. The pharmacological function of gabapentin is also distinct from that of benzodiazepines. [Conclusion] Gabapentin is a likely alternative to antipsychotics for treating delirium in PD patients. Further study will be necessary.
