The core treatment involves supportive care to rest the pancreas. This can be achieved mainly through diet control.
NPO (clears is probably ok for mild/moderate cases)
When restarting diet, eat small, low-fat meals and gradually advance over 3 to 6 days as tolerated
In patients with mild pancreatitis who are tolerating POs and can most likely be discharged. Instructions regarding a light diet and avoidance of alcohol is necessary
Volume resuscitation and constant monitoring of fluid status is important due to the risk of profound hypovolemia
Maintain urine output at 0.5 mL/kg
Maintain urine output at 0.5 mL/kg
For example:
Dilaudid 1mg or morphine 4mg IV PRN
Zofran 4mg IV PRN
Dilaudid 1mg or morphine 4mg IV PRN
Zofran 4mg IV PRN
Monitor for hypocalcemia and treat if symptomatic
Monitor for development of hypoglycemia or hyperglycemia
Consider albumin replacement if level <2g/dL
See hypertriglyceridemia for management of high triglycerides
Antibiotic use is often controversial and generally only required if there are obvious signs or sources of infection. Prophylactic use is not necessary 
Only indicated for necrosis, abscess, or infected pseudocyst / peripancreatic fluid
Imipenem-cilastatin, meropenem, or (fluoroquinolone + metronidazole)
Consider placement of an NG tube only if SBO or ileus is present and symptomatic
Indicated for patients with gallstone pancreatitis with retained CBD stone or cholangitis (recommended within 24 hours)
Alternative option for patients with gallstone pancreatitis who are poor operative candidates for cholecystectomy
Indicated for patients with biliary pancreatitis. Patients will generally will benefit from early cholecystectomy, as soon as the patient has recovered, preferably within the same hospital admission.
Symptomatic walled-off pancreatic fluid collections should be evaluated for a drainage procedure.
Acute pancreatitis
Gastroesophageal reflux disease 
Acute calculous cholecystitis
Peptic ulcer disease with or without perforation
Chronic pancreatitis
Gastritis
Duodenal hematoma
Pancreatitis