Proton pump inhibitors may cause elevation in faecal calprotectin levels

NICE has endorsed the use of faecal calprotectin (FCP) testing to enable clinicians to decide which of their patients presenting with diarrhoea may have inflammatory bowel disease or irritable bowel syndrome with diarrhoea (IBS-D). A normal result should reassure the clinician that their patient probably has IBS-D and this should obviate the need for a colonoscopy.

I work in a community-based gastroenterology service and we are now seeing young patients who are referred to us with symptoms highly suggestive of IBS who also have slight or modestly raised levels of faecal calprotectin. Many of these patients are also taking proton pump inhibitors. A paper with very small patient numbers in 2003 demonstrated that omeprazole¹ caused a modest rise in FCP but since then there has been no confirmatory study.

GPs seem to be aware that non-steroidal anti-inflammatory drugs cause a rise in FCP but the link to proton pump inhibitors is less well known.² Most of these patients come to colonoscopy and the findings are almost always normal. In these circumstances and, in the absence of alarm, lower gastrointestinal symptoms, it would be quite reasonable to stop the proton pump inhibitor as long as it is clinically safe to do so. One can then repeat the faecal calprotectin 4 weeks later. A persistently raised FCP merits further investigation. Endoscopy services are currently under severe pressure and it makes sense to avoid colonoscopy in young patients who have a very low risk of significant organic disease.