Non-invasive Vagal Nerve Stimulation Decreases the Need for Rescue Medication for Nausea Exacerbation in Patients...

Nausea exacerbations in patients with gastroparesis and functional dyspepsia (FD) require the use of rescue medications with concomitant adverse effects. We hypothesized that non-invasive vagal nerve stimulation (nVNS) may provide an effective and safer alternative for such symptoms.

This pilot study included 41 patients with chronic nausea, attributed to gastric etiology with or without delayed gastric emptying. After a one-week observation period, patients self-administered nVNS for exacerbations of nausea: 4 weeks on one side of the neck (left or right based on the patient's preference), followed by a 2-week washout and then another 4 weeks of nVNS on the other side. The primary endpoint was a reduction in the use of anti-nausea rescue medications.

Compared to baseline, nVNS reduced the average number of rescue medications used per day by half. The initial side of stimulation did not appear to influence the outcome. Although the use of nVNS in this study was not designed to influence chronic sustained symptoms, robust changes were also seen in abdominal pain, reflux, indigestion, constipation, depression, and some autonomic symptoms. Paradoxically, daily vomiting episodes increased during the 4-week period after nVNS was initiated but remained steady thereafter.

"As-needed" nVNS may reduce the use of rescue medications for exacerbations of nausea. Additionally, several relatively unexpected benefits across a variety of other symptoms were observed. These results should inform larger randomized sham-controlled trials in these disorders with limited therapeutic alternatives.

gov registration number NCT04857281. Date of registration, 2021-04-20.