Faecal calprotectin shedding after short-term treatment with non-steroidal anti-inflammatory drugs

Increased faecal calprotectin shedding indicates gastrointestinal mucosal inflammation. Methods: We studied the effect of short-term treatment with non-steroidal anti-inflammatory drugs (NSAIDs) on faecal calprotectin shedding in two randomized crossover studies, with treatment regimens of indomethacin or naproxen for 14 days in the first study (n = 16) and lornoxicam or naproxen for 7 days in the second study (n = 18). Results: The method's reproducibility and stability were satisfactory. Indomethacin and naproxen increased the faecal calprotectin significantly from a base line of 4.7 mg/l to 9.0 mg/l and 8.0 mg/l, respectively. Lornoxicam failed to increase the faecal calprotectin. Shedding after 7 days of naproxen treatment was positively correlated to gastroduodenal mucosal inflammation assessed by endoscopy. Conclusions: Although seemingly influenced by concurrent upper airway infections, the study indicates that the calprotectin test may be useful for monitoring the inflammatory response to NSAID treatment, even in a short-term setting.