Letters Section Editor: Robert M. Golub, MD, Senior Editor.
In Reply: The findings previously reported by Dr Grouzmann and colleagues regarding DPP4 activity in nasal tissues and the effect of DPP4 on substance P in patients with chronic rhinosinusitis provide a potential explanation and support for our clinical findings of increased risk of nasopharyngitis and headache in patients with type 2 diabetes treated with DPP4 inhibitors. In our review, we included only publicly available data from the published literature, which did not specify whether there was overlap among patients reporting nasopharyngitis and headache. Therefore, we cannot determine whether, in patients treated with DPP4 inhibitors, headache is a component of nasopharyngitis or if it constitutes a distinct clinical entity. We agree that it would be reasonable for clinicians to be cautious when using DPP4 inhibitors in patients with chronic rhinosinusitis or headache.
Pittas AG, Amori RE, Lau J. Adverse Effects of Incretin Therapy for Type 2 Diabetes—Reply. JAMA. 2007;298(15):1759-1760. doi:10.1001/jama.298.15.1760-a