Findings demonstrate the efficacy as well as safety of pre-procedural administration of rectal indomethacin in decreasing the incidence of post-extracorporeal shock wave lithotripsy (ESWL) pancreatitis.

• In this double-blind, randomized, placebo-controlled trial, a total of 1,370 patients aged 18 years or older with chronic pancreatitis and pancreatic stones (>5 mm in diameter) who were eligible for treatment with ESWL were randomized to receive 100 mg rectal indomethacin or identical glycerin (placebo) suppositories 30 min before ESWL.

• In the rectal indomethacin and placebo groups, post-ESWL pancreatitis occurred in 60 (9%) patients and in 84 (12%) patients, respectively (relative risk 0·71).

• In the rectal indomethacin and placebo groups, transient adverse events were experienced by 34% and 37% of the patients, respectively, with asymptomatic hyperamylasemia being the most common (28% vs 29% patients).

• The incidence of other complications and transient adverse events did not differ between groups.