Systematic review: is ingestion of paracetamol or non-steroidal anti-inflammatory drugs associated with exacerbations of inflammatory bowel disease?

Aim: To examine the published evidence on the association between paracetamol or non-steroidal antiinflammatory drugs and relapse in inflammatory bowel disease. Methods: Medline searches were performed till June 2004 and Embase till April 2003. Abstracts published in Gut and Gastroenterology from 1999 to 2004 were hand-searched. Twenty-nine relevant abstracts and papers were identified. Results: Twenty-two patients with relapse of inflammatory bowel disease following exposure to non-steroidal anti-inflammatory drugs have been described in case-reports. Four patients were re-exposed to non-steroidal anti-inflammatory drugs and relapsed again. Two had relapsed after taking a cyclo-oxygenase 2 inhibitor. One study described increased inflammatory activity and clinical relapse in some patients after challenge with naproxen or nabumetone. Fifteen epidemiological studies were identified. All had small sample sizes and many had methodological problems. Six studies found evidence for an association between non-steroidal antiinflammatory drug use and relapse of inflammatory bowel disease, but the association was significant in only two. Three studies suggested a relationship between paracetamol use and exacerbations of inflammatory bowel disease. Conclusions: Non-steroidal anti-inflammatory drugs may precipitate a relapse in some patients with inflammatory bowel disease. This may be an idiosyncratic reaction. The published evidence does not support the view that non-steroidal anti-inflammatory drugs are important in inducing relapse of inflammatory bowel disease. There is weak evidence that paracetamol may be more important.