P203 Oral omeprazole and diclofenac intake is associated with increased faecal calprotectin levels: a randomised open-label clinical trial

Abstract Background Non-steroidal anti-inflammatory drugs and proton pump inhibitors are known to affect the diagnostics of gastrointestinal disorders. The aim of this study was to investigate to what extent omeprazole, diclofenac or co-administration of these affects faecal calprotectin (FC) levels, and the normalisation interval after cessation. Methods Participants received 20 mg omeprazole daily for two weeks in the first sequence, 50 mg oral diclofenac three times daily for two weeks in the second and co-administration of these for two weeks in the third, with washout periods in between. The first two sequences were randomised to a different order. FC was measured on day 0, 4, 7, 14, 21, 28 and 35 and thereafter at 7-day intervals until normalisation in each sequence. Results Thirty-two healthy volunteers were included. During drug intake, 39% on diclofenac (median 70.8 µg/g; range 50.2-1080 µg/g), 53% on omeprazole (median 85.3 µg/g; range 51.1-249 µg/g) and 69% on omeprazole + diclofenac (median 101.5 µg/g; range 51.5-532 µg/g) had FC levels above normal. In the diclofenac sequence, FC returned to normal in all participants within two weeks of cessation and in the omeprazole and co-administration sequences, within three weeks of cessation. No statistical significant difference was found with respect to drug order. Conclusion Short-term intake of omeprazole, diclofenac or co-administration appears to increase FC levels. In patients with increased FC on omeprazole alone or in combination with diclofenac, a repeated FC test is recommended at least three weeks after cessation. On diclofenac alone, it is sufficient to repeat the FC test two weeks after cessation.