Optimal timing of rectal diclofenac in preventing post-endoscopic retrograde cholangiopancreatography pancreatitis.

Rectal nonsteroidal anti-inflammatory drug (NSAID) prophylaxis reduces incidence of post-endoscopic retrograde cholangiopancreatography (ERCP) pancreatitis. Direct comparisons to the optimal timing of administration, before or after ERCP, are lacking. Therefore, we aimed to assess whether timing of rectal NSAID prophylaxis affects the incidence of post-ERCP pancreatitis. We conducted an analysis of prospectively collected data from a randomized clinical trial. We included patients with a moderate to high risk of developing post-ERCP pancreatitis, all of whom received rectal diclofenac monotherapy 100-mg prophylaxis. Administration was within 30 minutes before or after the ERCP at the discretion of the endoscopist. The primary endpoint was post-ERCP pancreatitis. Secondary endpoints included severity of pancreatitis, length of hospitalization, and Intensive Care Unit (ICU) admittance. We included 346 patients who received the rectal NSAID before ERCP and 63 patients who received it after ERCP. No differences in baseline characteristics were observed. Post-ERCP pancreatitis incidence was lower in the group that received pre-procedure rectal NSAIDs (8 %), compared to post-procedure (18 %) (relative risk: 2.32; 95% confidence interval: 1.21 to 4.46,  = 0.02). Hospital stays were significantly longer with post-procedure prophylaxis (1 day; interquartile range [IQR] 1-2 days vs. 1 day; IQR 1-4 days;  = 0.02). Patients from the post-procedure group were more likely to be admitted to the ICU (1 patient [0.3 %] vs. 4 patients [6 %];  = 0.002). Pre-procedure administration of rectal diclofenac is associated with a significant reduction in post-ERCP pancreatitis incidence compared to post-procedure use.