AIM: To study if the angiotensin Ⅱ receptor blockers (ARB) losartan counteracts pancreatic hyperenzymemiaas measured 24 h after endoscopic retrograde cholan-giopancreatography (ERCP).METHODS: A triple-blind and placebo-controlled ran-domized clinical trial was performed at two Swedish hospitals in 2006-2008. Patients over 18 years of age undergoing ERCP, excluding those with current pancreatitis, current use of ARB, and severe disease, such as sepsis, liver and renal failure. One oral dose of 50 mg losartan or placebo was given one hour before ERCP. The relative risk of hyperenzymemia 24 h after ERCP was estimated using multivariable logistic regression, and expressed as odds ratio with 95% confidence intervals (CIs), including adjustment for potential remaining confounding.RESULTS: Among 76 participating patients, 38 were randomized to the losartan and the placebo group, re-spectively. The incidence rates of hyperenzymemia and acute pancreatitis among all 76 participating patients were 21% and 12%, respectively. Hyperenzymemia was detected in 9 and 7 patients in the losartan and placebo group, respectively. There were no major differences between the comparison groups regarding cannulation difficulty, findings, or proportion of patients requiring drainage of the bile ducts. There were, how-ever, more pancreatic duct injections, a greater extent of pancreatography, and more biliary sphincterotomies in the losartan group than in the placebo group. Losar-tan was not associated with risk of hyperenzymemia compared to the placebo group after multi-varible logis-tic regression analysis (odds ratio 1.6, 95%CI 0.3-7.8).CONCLUSION: In this randomized trial 50 mg losartan given orally had no prophylactic effect on development of hyperenzymemia after ERCP. AIM: To study if the angiotensin II receptor blockers (ARB) losartan counteracts pancreatic hyperenzymemiaas measured 24 h after endoscopic retrograde cholan-giopancreatography (ERCP). METHODS: A triple-blind and placebo-controlled ran-domized clinical trial was performed at two Swedish hospitals in 2006-2008. Patients over 18 years of age undergoing ERCP, excluding those with current pancreatitis, current use of ARB, and severe disease, such as sepsis, liver and renal failure. One oral dose of 50 mg losartan or placebo was given One hour before ERCP. The relative risk of hyperenzymemia 24 h after ERCP was estimated using multivariable logistic regression, and expressed as odds ratio with 95% confidence intervals (CIs), including adjustment for potential remaining confounding .RESULTS: Among 76 participating patients, 38 were randomized to the losartan and the placebo group, re-spectively. The incidence rates of hyperenzymemia and acute pancreatitis among all 76 participating patients w ere 21% and 12%, respectively. Hyperenzymemia was detected in 9 and 7 patients in the losartan and placebo group, respectively. There were no major differences between the comparison groups regarding cannulation difficulty, findings, or proport of patients requiring drainage of the bile ducts. There were, how-ever, more pancreatic duct injections, a greater extent of pancreatography, and more biliary sphincterotomies in the losartan group than in the placebo group. Losar-tan was not associated with risk of hyperenzymemia compared to the placebo group after multi-varible logis-tic regression analysis (odds ratio 1.6, 95% CI 0.3-7.8). CONCLUSION: In this randomized trial 50 mg losartan given orally had no prophylactic effect on development of hyperenzymemia after ERCP.