Oral allopurinol to prevent hyperamylasemia and acute pancreatitis after endoscopic retrograde cholangiopancreatography

AIM:To assess the efficacy of allopurinol to prevent hyperamylasemia and pancreatitis after endoscopic retrograde cholangiopancreatography(PEP).METHODS:One hundred and seventy patients were enrolled and randomized to two groups:a study group(n=85)who received 300 mg of oral allopurinol at 15 h and 3 h before endoscopic retrograde cholangiopancreatography(ERCP)and a control group(n=85)receiving an oral placebo at the same times.Main Outcome Measurements included serum amylase levels and the number severity of the episodes of pancreatitis.Serum amylase levels were classified as normal(<150 IU/L)or hyperamylasemia(>151 IU/L).Episodes of PEP were classified following Ranson's criteria and CT severity index.RESULTS:Gender distribution was similar between groups.Mean age was 53.5±18.9 years for study group and 52.8±19.8 years for controls.Also,the distribution of benign pathology was similar between groups.Hyperamylasemia was more common in the control group(P=0.003).Mild PEP developed in two patients from the study group(2.3%)and eight(9.4%) from control group(P=0.04),seven episodes were observed in high-risk patients of the control group(25%) and one in the allopurinol group(3.3%,P=0.02).Risk factors for PEP were precut sphincterotomy(P=0.02),pancreatic duct manipulation(P=0.002)and multiple procedures(P=0.000).There were no deaths or side effects.CONCLUSION:Oral allopurinol before ERCP decreased the incidences of hyperamylasemia and pancreatitis in patients submitted to high-risk procedures.

Antioxidant drugs to prevent post-endoscopic retrograde cholangiopancreatography pancreatitis:What does evidence suggest?

AIM:To determine whether or not the use of antioxidant supplementation aids in the prevention of post-endoscopic retrograde cholangiopancreatography pancreatitis.METHODS:A systematic review of randomized controlled trials(RCTs) was made to evaluate the preventive effect of prophylactic antioxidant supplementation in post-endoscopic retrograde cholangiopancreatography pancreatitis(PEP).The inclusion criteria included:acute post-endoscopic retrograde cholangiopancreatography pancreatitis in adults; randomized clinical trials with the use of any antioxidant as an intervention compared with placebo,to reduce PEP.The outcome measure was the incidence and severity of PEP.Twelve RCTs involving 3110 patients since 1999 wereincluded.The antioxidants used were selenite,β-carotene,and pentoxifylline(each one in one trial),N-acetylcysteine(NAC) in three trials,and allopurinol in six trials.The group of patients treated with NAC received different doses; either oral or intravenous,and allopurinol-treated patients received five different oral doses in two different administration periods.The results are expressed with raw numbers,proportions,as well as mean and standard deviations.The incidence of pancreatitis between groups was analyzed with Pearson's χ2 test or Fisher's exact test(F).The main outcome is expressed as relative risks and 95%CI.RESULTS:The incidence of pancreatitis in all antioxidant treatment groups was 8.6%,whereas it was 9.7% in the control group.The antioxidants used were selenite,β-carotene,and pentoxifylline(each one in one trial),NAC in three trials,and allopurinol in six trials.In allopurinol trials,three different dosifications were used; two trials reported a low dosage(of less than 400 mg),two trials reported a moderate dose(600 mg) and the remaining two employed higher doses(more than 900 mg).Supplementation was not associated with a significant reduction in the incidence of PEP [relative risk(RR) = 0.93; 95%CI:0.82-1.06; P = 0.28].In addition,the incidences of PEP in patients treated with allopurinol and those treated with other antioxidants were similar to that observed in patients who received the placebo(RR for trials with allopurinol,0.92; 95%CI:0.78-1.08; P = 0.31) and,with the use of other antioxidants,the incidence of PEP was 8.9%,whereas it was 9.7% in the control group(RR = 0.95; 95%CI:0.77-1.18; P = 0.19).CONCLUSION:Antioxidant supplementation shows no beneficial effect on the incidence of PEP.There is a lack of robust trials to support the use of antioxidants for prevention.