Review 10.1517/14740338.5.4.xxx © 2006 Informa UK Ltd ISSN 1474-0338 1 General Drug-induced side effects affecting the gastrointestinal tract Rupert WL Leong † & Francis KL Chan † The University of New South Wales, Department of Gastroenterology and Hepatology, Bankstown-Lidcombe Hospital, Eldridge Road, Bankstown, NSW 2200, Sydney, Australia With the ever growing armamentarium of pharmacological agents, the gas- trointestinal drug-induced side effects of dyspepsia, nausea, vomiting, diar- rhoea and constipation are increasingly seen. They are often self-limiting and without serious sequelae, but of greater concern is drug-induced mucosal ulceration that can manifest as gastrointestinal haemorrhage, stric- ture and perforation. These complications are mainly attributable to NSAIDs and aspirin, which can injure the mucosa anywhere along the gas- trointestinal tract. These iatrogenic serious side effects can be reduced with co-prescription of a proton pump inhibitor, substitution of a COX-2 inhibitor and eradication of Helicobacter pylori when the bacterium is present. Other recognised gastrointestinal complications include small intestinal dia- phragm, microscopic colitis, a range of hepatotoxic effects and pancreatitis. The introduction of new classes of drugs has resulted in new adverse effects that require consideration in patients presenting with gastroenterological symptoms. These include pill oesophagitis from bisphosphonates and ischae- mic colitis relating to serotonin antagonists. Here, the authors review the lit- erature on drug-induced complications of the gastrointestinal tract and present the pertinent management issues relevant to clinical practice. Keywords: aspirin, diaphragm, haemorrhage, NSAID, oesophagitis, perforation, ulcer Expert Opin. Drug Saf. (2006) 5(4):xxx-xxx 1. Introduction With an ever increasing array of novel chemical compounds and translational research, more new drugs are being developed. When marketed, there may not have been adequate clinical exposure or the follow-up time necessary to recognise impor- tant drug-induced complications. The increasing complexity of agents has also resulted in greater side effect profiles and risk of drug interactions from polyphar- macy. On average, unwell patients are receiving more drugs, corresponding to increasing likelihood of adverse reactions. The availability of drugs over-the-counter and use of poorly regulated complementary alternative medicines add to the com- plexity of identifying the culprit agent. Gastrointestinal drug side effects, especially from NSAIDs and low-dose aspirin, are common and may result in variable mor- bidity that ranges from nausea and dyspepsia, to life-threatening events through the development of complicated gastroduodenal ulcers. Furthermore, drug adverse effects add to the direct and indirect cost of the healthcare system [1]. This article focuses on the drug-induced adverse reactions on the gastrointestinal lumen. An estimated three-quarters of a million people are injured or die in hospitals each year from adverse drug events [2]. Aspirin, NSAIDs, analgesics, digoxin, antico- agulants, diuretics, antimicrobials, glucocorticoids, antineoplastics and hypoglycae- mic agents account for 90% of reactions [3]. The diagnosis of a drug-induced gastrointestinal side effect is often made clinically. The introduction of the drug is temporally associated with the adverse reaction, which resolves on cessation of the 1. Introduction 2. Oral cavity 3. Oesophageal 4. Stomach and duodenum 5. Small intestine 6. Colon 7. Expert opinion and conclusions