Erythromycin‐induced abdominal pain

Abstract

Dear Sir, Erythromycin is a common cause of abdominal pain. It is thus surprising that many clinicians overlook the drug when investigating the aetiology of severe abdominal cramps. A 10-year-old white boy diagnosed as having Mycoplasma pneumoniae chest infection was put on erythromycin base 250 mg orally every 6 hours. He developed crampy epigastric pain after the first two doses and the drug was discontinued. The pain occurred in bouts, and did not respond to antispasmodics. It increased in severity after discontinuation of the medication. The patient was admitted to the paediatric department and put on intravenous erythromycin lactobionate. The abdominal pain worsened. Plain film of the abdomen, ultrasound and endoscopy all produced normal results. The erythromycin was discontinued and the patient switched to oral tetracycline. The abdominal pain subsided gradually and disappeared completely after 36 hours. Erythromycin base and its salts are often used in clinical practice. The most frequent side-effects of oral erythromycin preparations are gastrointestinal; these become more common with intravenous use and have been described as occurring with erythromycin lactobionate.1 Erythromycin mimics the effect of motilin, the gastrointestinal polypeptide. The mechanism probably operates by the drug's acting as a motilin agonist through inhibiting motilin binding to its receptors, which are confined mainly to the gastric antrum and proximal duodenum.2 Individual susceptibility also plays a part.3 Last year, in a randomised, double-blind placebo-controlled study in adults, Bowler et al demonstrated that erythromycin gastrointestinal toxicity is common. They showed that it may be reduced by pretreatment with glycopyrrolate, through a presumed peripheral anticholinergic mechanism.4 Adverse reaction to erythromycin should thus be considered in the differential diagnosis of patients presenting with acute severe abdominal pain.