The objective of this study is to evaluate the effects of naloxegol (a peripheral mu-opioid
receptor antagonist [PAMORA]) in opioid-related gastroparesis on 1) symptoms of
gastroparesis; 2) gastric emptying; and 3) pain control. The endpoints will be gastroparesis
symptoms (PAGI-SYM), gastric emptying (GEBT), and pain control (McGill Pain Inventory). The
hypothesis to be tested is that naloxegol improves symptoms of gastroparesis in patients who
are taking opioids as well as improves their gastric emptying while maintaining control of
patient's pain. This study will entail an initial double-blind, randomized,
placebo-controlled, 4-week treatment period of naloxegol vs placebo in patients with
opioid-related gastroparesis followed by a 4-week open label period to demonstrate the
improvement in symptoms and gastric emptying with naloxegol.