Safe Use of Erythromycin For Refractory Gastroparesis After Small Bowel Transplantation

Current therapeutic options with prokinetic agents for posttransplant gastroparesis are limited. Erythromycin is associated with adverse reactions, including corrected QT interval prolongation and cytochrome P450 3A4 isoenzyme inhibition. The use of erythromycin has been avoided in patients undergoing treatment with cyclosporine or tacrolimus because of significant fluctuations in therapeutic immunosuppression levels. We report herein the successful use of erythromycin after visceral transplant to treat delayed gastric emptying. Two patients were managed with oral erythromycin (initial dose of 750 mg/d divided into 3 doses) for gastroparesis after visceral transplant. Patient 1 was a woman aged 42 years with a history of chronic intestinal pseudo-obstruction syndrome who underwent isolated small bowel transplant with dual (gastric and duodenal) proximal allograft anastomosis. Posttransplant gastroparesis was initially managed with oral metoclopramide. The patient also required high doses of tacrolimus (36 mg/d) to maintain adequate immunosuppression levels. The decision was made to change metoclopramide to erythromycin, which significantly decreased the daily tacrolimus dose requirement (from 36 to 9 mg/d), with resolution of nausea and intermittent bloating symptoms. Patient 2 was a woman aged 35 years with ultra-short gut syndrome after extensive enterectomy due to intestinal volvulus who underwent uneventful combined intestinal and colon transplant. Conventional pharmacologic therapy for gastroparesis was initiated after surgery without success. Erythromycin was started 15 days posttransplant, with significant improvement in her symptoms, and discontinued 47 days post-transplant. To maintain therapeutic levels (8-10 mg/dL), daily tacrolimus dose was decreased 75.8% and 36.5% for patients 1 and 2, respectively. No significant side effects associated with erythromycin use were observed in either patient. Our findings here suggest that erythromycin may be safely used for gastroparesis after small bowel transplant. Close monitoring of immunosuppressive drug levels and dose adjustments of other medications affected by inhibition of cytochrome P450 3A4 are advised.