Objective: To describe the association of clarithromycin, used to treat Helicobacter pylori infection and duodenal ulceration, with pseudomembranous colitis in two patients.
Setting: St Mary's Hospital, London, UK.
Patients: Two female patients aged 77 and 78 years, admitted with duodenal ulceration and H. pylori infection.
Intervention: Clarithromycin (500 mg three times daily) was administered concurrently with omeprazole (40 mg once daily).
Outcome measures: After an initial improvement in symptoms both patients experienced persistent Clostridium difficile-associated diarrhoea.
Conclusions: High-dose clarithromycin should be used with caution for the treatment of H. pylori infection associated with gastroduodenal ulceration. The drug may induce antibiotic-associated colitis which can lead to morbidity and mortality, particularly in the elderly.