Bodyweight-Adjusted Nonsteroidal Anti-inflammatory Drugs Dose in the Prevention of Post-endoscopic Retrograde Cholangiopancreatography Pancreatitis

Objectives: Although rectal nonsteroidal anti-inflammatory drugs (NSAIDs) reduce the incidence of postendoscopic retrograde cholangiopancreatography pancreatitis (PEP), their optimal dosage is unknown. Given possible interindividual variability in the pharmacodynamics of NSAIDs, we hypothesized that the dose required to achieve adequate PEP prophylaxis varies with body weight. Materials and Methods: We conducted an analysis using single-center, prospective, observational cohort study data. The primary outcome was PEP incidence by NSAID dosage per body weight (mg/kg). Patients meeting the inclusion criteria were classified into 3 groups. Results: We included 891 patients, with 400, 454, and 37 patients in the control group with no NSAID therapy, the NSAID <1.0 mg/kg group, and the NSAID ≥1.0 mg/kg group, respectively. In the adjusted cohort, the odds ratio of PEP was 0.18 (95% confidence interval: 0.041–0.79; P = 0.023) for NSAID ≥1.0 mg/kg and 1.3 (95% confidence interval: 0.76–2.3; P = 0.31) for NSAID <1.0 mg/kg compared to the control group without NSAID. Conclusions: PEP was not prevented by NSAID dosages below 1.0 mg/ kg body weight whereas a dosage above 1.0 mg/kg body weight had a significant prophylactic effect. An NSAID dosage adjusted to body weight may be necessary to achieve an adequate prophylactic effect against PEP.