Drug fever and acute inflammation from hypercytokinemia triggered by dipeptidyl peptidase‐4 inhibitor vildagliptin

A 69‐year‐old man started taking the dipeptidyl peptidase‐4 inhibitor, vildagliptin. One week later, C‐reactive protein and plasma immunoglobulin E levels were markedly elevated, and the vildagliptin was stopped. After the patient's laboratory findings were normalized, we decided to restart vildagliptin with the patient's agreement. The next day, he had a high fever, and C‐reactive protein and procalcitonin levels were elevated. Although we failed to find a focus of infection, we started antibiotics therapy. Two days later, the high fever had improved, and the C‐reactive protein level had decreased. A drug lymphocyte stimulation test showed a positive result for vildagliptin. We examined various kinds of cytokine and infection markers just before and after the treatment with vildagliptin. Finally, we diagnosed the patient with vildagliptin‐induced drug fever, probably based on the increase of various inflammatory cytokine levels and the response to this. Taken together, we should be aware of the possibility of vildagliptin inducing drug fever and/or acute inflammation.