Esophageal dysfunction more common in some patients on opioids

Last Updated: 2015-06-19

By Larry Hand

NEW YORK (Reuters Health) - Patients who have taken opioids for pain relief within 24 hours of esophageal pressure tomography (EPT) are more likely to have esophageal dysfunction than are those who stopped treatment earlier, according to new research.

"Opioid pain medications may contribute to esophageal motor dysfunction and symptoms in a subset of patients with dysphagia," Dr. Michael D. Crowell of the Mayo Clinic Arizona in Scottsdale told Reuters Health by email.

Dr. Crowell and colleagues reviewed data on 121 opioid users, 66 (55%) of whom were on current opioid medications and 55 (45%) who were off opioid medications for at least 24 hours. The patients underwent high-resolution manometry (HRM) studies between March 2010 and August 2012.

Demographic characteristics were similar between groups. Dysphagia was the most common (55%) reason for performing HRM. Other reasons included gastroesophageal reflux disease (26%), chest pain (12%), hiatal hernia (2%) and nausea and vomiting (2%).

Most patients (98%) took short-acting opioids, and medications included oxycodone, hydrocodone, morphine, codeine and hydromorphone, Dr. Crowell and colleagues report in the American Journal of Gastroenterology, online June 2.

Of the 86% of patients who underwent esophagogastroduodenoscopy, 77% had normal appearance of the esophagus, while the others had conditions including Barrett's esophagus, furrowing and esophagitis.

Patients studied on opioid medications had significantly more esophagogastric junction (EGJ) outflow obstruction than did patients off medication (27% vs. 7%, p=0.004).

They also had significantly higher mean 4s integrated relaxation pressure (10.71 vs. 6.6 mmHG, p=0.025), and their resting lower esophageal sphincter (LES) pressures were numerically though not statistically higher (31.61 vs. 26.98, p=0.25).

In addition, achalasia type III, distal esophageal spasm, jackhammer esophagus, and fragmented peristalsis were more common in patients on opioid medication.

"We speculate that in the esophagus, opioids may preferentially act on nitric oxide-releasing neurons rather than cholinergic neurons, leading to unopposed excitatory input that can result in spastic esophageal motor activity," the researchers wrote.

"The findings in our study support the notion that opiates may affect esophageal motility by interfering with inhibition of contractions. Impaired LES relaxation as seen in EGJ outflow obstruction, and the reduced latency seen in distal esophageal spasm, can both be attributed to diminished inhibitory signaling, or alternatively, unopposed excitatory input," they added.

"Prospective studies are needed with patients studied on and off opioid pain medications to determine if esophageal motor dysfunction resolves," Dr. Crowell said. "Clinical symptoms and esophageal manometry findings in patients on opioid pain medications should be interpreted with caution, and if at all possible, patients should be evaluated after stopping these medications."

Opioid-induced bowel pain (OIBD) "is an increasingly important problem to consider as we continue to try to treat pain, whether that be cancer-associated pain or non-cancer-associated pain." Dr. Ankush Sharma, of the University of California Irvine Medical Center and Medical School, who has conducted research in this area, told Reuters Health by email.

"OIBD ends up costing millions upon millions of dollars in readmissions, prolonged lengths of stay, and morbidity associated with this. The solution to the problem is first to be aware of the issue and educating patients to be cognizant that their bowel movements will slow down, and administering prophylactic medicines such as stool softeners to prevent the problem from happening," he said.

"Furthermore, if and when this happens, newer medications such as methylnaltrexone and oral lubiprostone have demonstrated such rapid and effective results that they can be prescribed in a hospital (methylnaltrexone) and outpatient setting (lubiprostone), respectively," Dr. Sharma added.

"Research that is being done and needs to continue is to compare head to head oral laxatives versus methylnaltrexone versus even lubiprostone to see if and what are the significant differences in terms of costs, lengths of stay, and morbidity to the patients. Current studies tend to compare these different drugs to placebo, and we know based on their mechanisms of action that certainly these drugs will be far more effective than placebo," he said.

The authors reported no funding or disclosures.

SOURCE: http://bit.ly/1dxfXsb

Am J Gastroenterol 2015.