Incidence of Post-ERCP Pancreatitis in Patients Receiving Rectal Indomethacin vs. Compounded Rectal Diclofenac Prophylaxis

Background and aims: Endoscopic retrograde cholangiopancreatography (ERCP) carries a 3-15% risk of post-ERCP pancreatitis (PEP). Rectal indomethacin reduces the risk of PEP, but its cost has increased more than 20-fold over the past decade. Rectal diclofenac is also used to prevent PEP but is not commercially available in the United States. The aim of this study is to compare the incidence of PEP after administration of commercially available rectal indomethacin versus compounded rectal diclofenac and assess financial implications.

Methods: ERCP cases at our institution with administration of 100 mg rectal indomethacin or 100 mg compounded rectal diclofenac between May 2018 and January 2022 were retrospectively reviewed. The incidence and severity of PEP was compared between the indomethacin (n = 728) and diclofenac (n = 304) groups. Risk factors (young age, female sex, history of pancreatitis or PEP, sphincterotomy during procedure, pancreatic indication, trainee involvement) and protective factors (prior sphincterotomy, pancreatic duct stenting) for PEP were compared between groups.

Results: 60 patients (8.2%) in the rectal indomethacin group and 25 patients (8.2%) in the compounded rectal diclofenac group developed PEP, resulting in moderate or severe PEP in 9 (15.0%) and 2 (8.0%) patients, respectively. The compounded rectal diclofenac group had more trainee involvement (46.1% vs. 32.8%, p = 0.0001) and more prior sphincterotomy cases (15.8% vs. 10.6%, p = 0.0193) compared to the rectal indomethacin group; no statistically significant differences were observed in all other risk and protective factors. Following switch to compounded rectal diclofenac, institutional annual cost savings amounted to $441,460.62 and patient charge decreased 45-fold.

Conclusion: This retrospective single-center real-world analysis showed similar efficacy of rectal indomethacin and compounded rectal diclofenac in preventing PEP but demonstrates substantial cost savings after switching to compounded rectal diclofenac.