EFFECTS OF ORAL ERYTHROMYCIN ON ESOPHAGEAL PH AND PRESSURE PROFILES IN PATIENTS WITH GASTROESOPHAGEAL REFLUX DISEASE

Erythromycin, a possible motilin agonist, is a potent gastrokinetic ag ent that may increase the lower esophageal sphincter pressure. Therefo re, we assessed the effects of erythromycin in two dosages (250 and 50 0 mg per os four times a day) on esophageal pH and pressure profiles i n reflux patients using prolonged ambulatory monitoring systems. Studi es were blinded, placebo-controlled with randomized crossover design. Patients took each drug for three days prior to studies, with erythrom ycin serum levels obtained the day of esophageal studies. Erythromycin 250 mg four times a day had no effect on esophageal contraction press ures or peristalsis during the day or meal periods. In the supine posi tion, however, erythromycin significantly (P = 0.012) decreased esopha geal contraction velocity and showed a strong trend (P = 0.059) toward s increasing the percentage of peristaltic waves. Despite these potent ially beneficial effects an esophageal clearance, no significant diffe rence in acid exposure times during 24-hr pH studies were observed bet ween placebo and low-dose erythromycin. High-dose erythromycin (500 mg four times a day) was associated with drug levels in the typical anti biotic efficacy range (normal 1-3 mu g/ml; patients 1:7-7.0 mu g/ml), but, here again, there was no significant difference in all acid reflu x parameters between placebo and erythromycin phases. Therefore, ''sta ndard'' doses of erythromycin have no important clinical effects on es ophageal pressures or acid reflux parameters.