Association between dipeptidyl peptidase-4 inhibitor and aspiration pneumonia: disproportionality analysis using the spontaneous reporting system in Japan.

Since DPP-4 inhibitors prevent the degradation of substance P involved in swallowing reflex, DPP-4 inhibitors were expected to prevent dysphagia and aspiration pneumonia. However, this study revealed that DPP-4 inhibitors strongly were associated with onset rather than preventing aspiration pneumonia. This result suggests that DPP-4 inhibitors may affect the immune function associated with the development of aspiration pneumonia. Furthermore, there is a possibility that the amount of DPP-4-Is used clinically cannot increase the amount of substance P in sufficient quantity to prevent aspiration pneumonia.