A Randomized Clinical Trial on the Effect of a Two-Week Treatment with Capsaicin on Older Patients with Oropharyngeal Dysphagia

BACKGROUND: Acute studies have shown that TRPV1 agonists have improved both the biomechanics and neurophysiology of the swallowing response. The aim of this study was to assess the effect of a two-week treatment with capsaicin in older patients with oropharyngeal dysphagia (OD). METHODS: A prospective, double-blind, randomized clinical trial was conducted. A total of 51 older patients with OD (PAS > 2) were included and treated for two weeks with 10 mL capsaicin 10 μM before meals (three times a day). Videofluoroscopy was used to examine swallowing biomechanics, and pharyngeal sensory (pSEP) and motor evoked potentials (pMEP) were used to assess neurophysiological responses. Salivary neuropeptides SP and CGRP were quantified using ELISA. RESULTS: The mean age of patients was 78.51 ± 6.04 years. The 32 patients treated with capsaicin showed a significant reduction in PAS score (4.7 ± 1.7 vs 3.9 ± 1.5, p = 0.02), time to LVC (405.3 ± 124.2 ms vs 366.6 ± 154.4 ms, p = 0.04), and latency of the N1 peak of pSEPs (88.3 ± 17.1 ms vs 74.4 ± 17.6 ms, p = 0.007) and had significant changes in brain activation. Improvement in time to LVC correlated significantly with N1 peak latency (p = 0.03), and salivary substance P increased by 75.8%. In contrast, the biomechanics and neurophysiology of the swallowing response in the 19 patients of the placebo group did not show significant improvement. DISCUSSION: Two weeks of capsaicin stimulation in older patients with OD were found to improve sensory and motor swallowing functions by enhancing pharyngeal sensitivity and reducing the time to LVC. CONCLUSION: Capsaicin administered over 2 weeks was found to improve swallowing safety and the biomechanics and neurophysiology of the swallowing response. TRPV1 agonists could be the basis of long-term pharmacological treatments for OD.