This is a prospective, single-center, randomized, placebo-controlled, double-blind clinical trial that aims to investigate the beneficial and harmful effects of prophylactic use of imipenem in patients with predicted severe acute pancreatitis. All patients with first attack of acute pancreatitis, an onset of disease less than 72h before admission, and an APACHE II score ≥ 8 calculated within the first 24h from admission will be enrolled.

Inclusion Criteria:

• diagnosis of acute pancreatitis defined by the Revised 2012 Atlanta Criteria
• first manifestation of acute pancreatitis regardless of etiology
• APACHE II ≥ 8 calculated within the first 24 hours of admission
• onset of symptoms < 72 hours before admission

Exclusion Criteria:

• age < 18 years
• pregnant and breastfeeding women
• active and documented infection at admission
• concomitant antibiotic treatment or antibiotic treatment present within 72 hours before enrollment
• acute pancreatitis diagnosed at surgery
• active malignancy
• known immune deficiency
• patients with chronic pancreatitis
• patients unwilling to participate in the trial