We previously showed an association between chronic opioid use and esophageal motor dysfunction characterized by esophagogastric junction outflow obstruction, distal esophageal spasm, achalasia type III, and Jackhammer esophagus. Assessment of response to multiple rapid swallows (MRS) during high-resolution esophageal manometry (HRM) enables detection of impaired inhibition during MRS. Healthy subjects respond to MRS by deglutitive inhibition during MRS followed by an augmented contraction with higher vigor than single swallows. Hypothesis: during MRS, opioids may interfere with deglutitive inhibition and may enhance post MRS contraction. Aim: compare response to MRS in opioid users, non-users and healthy controls.
Response to MRS was evaluated in 200 patients with esophageal symptoms (100 chronic opioid users on oxycodone, hydrocodone, or tramadol for ≥3 months, 100 not on opioids), and 19 asymptomatic healthy controls that underwent HRM. Patients with prior gastroesophageal surgery, pneumatic dilation, esophageal botulinum toxin injection within 6 months of HRM, esophageal stricture, achalasia type I or II, and scleroderma were excluded. Demographic and symptom data were extracted from a prospectively maintained motility database. Response to MRS was evaluated for complete versus incomplete inhibition (contractility with DCI >100 mmHg-sec-cm during MRS), and presence of post MRS contraction augmentation (DCI post MRS greater than mean DCI for single swallows). Categorical variables were analyzed by chi square.
Patients were older than controls (Table 1). HRM indications are shown in Table 2. Incomplete inhibition during MRS was significantly more frequent in chronic opioid users compared to patients not on opioids and healthy controls (26% vs 11% vs 0% P = 0.002; Figure 1). There was a significant difference in the rate of incomplete MRS inhibition for patients on oxycodone, hydrocodone, and tramadol (27% vs 34% vs 22% P = 0.002). The proportion of patients with augmentation post MRS was similar for opioid users, non-opioid users and healthy controls (P = 0.05).
Impaired deglutitive inhibition during MRS was significantly more frequent among opioid users compared to non-opioid users and healthy controls. This was more common with stronger opioids (oxycodone and hydrocodone) compared to tramadol. These findings support our hypothesis that opioids interfere with inhibitory signals in the esophagus.