ERYTHROMYCIN ENHANCES GASTRIC-EMPTYING IN PATIENTS WITH GASTROPARESISAFTER VAGOTOMY AND ANTRECTOMY

We studied the effect of erythromycin on gastric emptying in nine pati ents with gastroparesis following truncal vagotomy and antrectomy, and assessed their clinical response to chronic oral erythromycin. Gastri c emptying was evaluated using a solid-phase radiolabeled meal. Patien ts were studied after erythromycin 200 mg intravenously (N = 9) and af ter an oral suspension of erythromycin 200 mg (N = 7) each given 15 mi n after ingestion of the meal. Three parameters of gastric emptying we re analyzed: half-emptying time (T1/2), area under the curve, and perc ent gastric residual at 2 hr. Nine patients were subsequently placed o n oral suspension erythromycin 150 mg three times a day before meals ( range 125-250 mg three times a day) and symptoms of nausea, vomiting, postprandial fullness, and abdominal pain were assessed before and aft er erythromycin. Intravenous erythromycin markedly accelerated the gas tric emptying (all three parameters studied) of solids (P < 0.01) in s even of nine patients with postsurgical gastroparesis [baseline T1/2 1 54 +/- 15 min; after intravenous erythromycin, T1/2 56 +/- 17 min (mea n +/- SEM)]. Oral erythromycin enhanced (P < 0.05) the gastric emptyin g rate (T1/2, area under the curve) in five of seven patients (baselin e T1/2 146 +/- 16 min; after oral erythromycin, T1/2 87 +/- 20 min). O f the nine patients who were placed on oral maintenance erythromycin, three showed clinical improvement after two weeks. In summary, erythro mycin significantly enhances gastric emptying in many patients with va gotomy and antrectomy-induced gastroparesis; however, only a small sub set of patients respond clinically to chronic oral erythromycin.