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

Table 1 Demographics and ERCP data

	Allopurinol n = 85	Placebo n = 85	P
Age	53.5 ± 18.9	52.8 ± 19.8	0.82
Gender M/F	36/49	34/51	0.86
Diagnosis
Benign
Choledocholitiasis	35	35	0.51
Iatrogenic injury of the biliary tract	11	14	0.48
Chronic pancreatitis	3	1	0.31
Chronic hepatopathy	2	2	0.60
Sphincter of oddi dysfunction	2	2	0.60
Mirizzi’s syndrome	1	0	0.50
Malignant
Pancreatic adenocarcinoma	11	12	0.82
Cholangiocarcinoma	4	5	0.50
Periampullary carcinoma	2	2	0.60
Gallbladder cancer	0	1	0.50
Normal cholangiography	8	5	0.48
Failed procedure	6	6	0.61
Total	85	85

Table 2 Procedural details, endpoints and post-ERCP morbidity n (%)

	Allopurinol group n = 85	Placebo group n = 85	P
Procedural details
Total procedural time (min)	37.8 ± 11.9	38.2 ± 12.4	0.82
Cannulation time (min)	15.4 ± 5.5	15.6 ± 5.6	0.81
Pancreatic cannulation and injection	24 (24.7)	18 (21.1)	0.18
Number of injections	1.23 ± 0.42	1.27 ± 0.44	0.60
Acinarization	9 (10.5)	9 (10.5)	0.58
Invasive diagnostics
Cytology	15 (17.6)	17 (20)	0.42
Intrabiliary biopsy	2 (2.3)	2 (2.3)	0.69
Therapeutics
Any Therapeutics	71 (83.5)	74 (87)	0.51
Precut sphincterotomy	15 (17.6)	18 (21.1)	0.56
Biliary sphincterotomy	20 (23.5)	17 (20)	0.57
Stone extraction	29 (34.1)	27 (31.7)	0.74
Biliary stenting	32 (37.6)	37 (43.5)	0.43
Pancreatic stenting	2 (2.3)	3 (3.5)	0.64
End points
Hyperamylasemia	5 (5.8)	18 (21.1)	0.003
Pancreatitis	2 (2.3)	8 (9.4)	0.049
PEP in low-risk procedures	1/55 (1.8)	1/57 (1.7)	0.70
PEP in high-risk procedures	1/30 (3.3)	7/28 (25)	0.02
ERCP morbidity
Bleeding	2 (2.3)	2 (2.3)	0.69
Perforation	1 (1.1)	0	0.50

Table 3 Summary of randomized trials using allopurinol to prevent post-ERCP pancreatitis

Study (year), SC vs MC, country	n	Dose, mg	Allopurinol vs placebo PEP rates	Percentage high risk1	Comment
Budzyńska et al[31] (2001) SC, Poland	300	4002	12.1% vs 7.9%; 12 vs 8	0	3-arm study, with third arm (n = 100) given prednisone
Kastinelos et al[30] (2005) SC, Greece	250	12003	3.2% vs 17.8%; 4 vs 21	0	2 patients with suspected SOD
Mosler et al[32] (2005) MC, USA	701	9004	13.0% vs 12.1%; 46 vs 42	70.2	4% absolute benefit in high-risk patients; 4% absolute harm in average risk
Romagnuolo et al[33] (2008) MC, Canada	586	3005	5.5% vs 4.1%; 16 vs 12	11.3	Harm in average risk patients; benefit in high-risk patients
Current study (2009) SC, Mexico	170	6006	2.3% vs 9.4%; 2 vs 8	34.1	21.7% absolute benefit in patients with high-risk procedures favoring allopurinol, no difference in low-risk procedures
Raw pooled	2007 (1008 vs 999)	-	7.9% vs 9.1%; 80 vs 91	-	1.2% difference (95% CI, 3.2% to 2.0%)

¹As defined in this protocol, namely sphincter manometry and/or pancreatic therapy. Other higher-risk cases (e.g. precut sphincterotomy or suspected SOD) were not considered;

²200 mg 15 h before, 200 mg 3 h before;

³600 mg 15 h before, 600 mg 3 h before;

⁴600 mg 4 h before, 300 mg 1 h before;

⁵300 mg 1 h before;

⁶300 mg 15 h before, 300 mg 1 h before; SC: Single centre; MC: Multicenter.