Effect of loperamide on gastro-oesophageal reflux

We have recently shown that morphine reduces gastro-oesophageal reflux (GOR) by stimulating opioid receptors. Our aim was therefore to investigate the effect of loperamide, a peripheral opioid agonist, on GOR.

Nine patients with GOR disease underwent two ambulatory 24-h intra-oesophageal pH monitoring sessions separated by a period of at least 7 days under double-blind randomized conditions during the administration of placebo or loperamide solution p.o. (8 mg + 4 mg + 4 mg, 12 h and 2 h before, and 7 h after the start of the recording).

Twenty-four-hour oesophageal acid exposure and the number of reflux episodes/hour were similar under the two experimental conditions: a median (IQ range) of 6.2% (3.3%-11.0%) of the time at pH < 4 and 2.6 (1.6-3.5)/h during placebo versus 8.8% (3.7%-14.8%) and 2.8 (2.3-4.9)/h during loperamide (P = ns). Acid clearance time was also similar: 1.8 +/- 0.3 min versus 1.6 +/- 0.2 min (P = ns).

Loperamide did not decrease GOR, thus suggesting that an opioid agonist may not be useful in the treatment of GOR disease.