Opioids act on opioid receptors located in the brain as well as in the gastrointestinal (GI)
tract to induce changes in motility. A variety of studies have linked chronic opioid use with
changes in intestinal and to a lesser extent esophageal motility. Less is known about acute
administration effects on distal esophageal motility and LES and even less with respect to
proximal esophagus, UES and pharynx. Codeine, an opioid receptor agonist, by acting both
centrally as well as in the periphery may induce changes in parts of the GI tract implicated
in deglutition. Therefore, to evaluate the hypothesis the researchers will study motility
patterns in the pharynx, UES, proximal and distal esophagus and LES in 22 healthy volunteers
receiving placebo or codeine (60 mg) in a double-blind randomized cross-over controlled
fashion. Motility patterns will be studied using state-of-the-art criteria and analytic tools
(Chicago 3.0, AIMPlot analysis).