Efficacy Study of Δ9-THC to Treat Chronic Abdominal Pain

Inclusion Criteria: * Patient has chronic pancreatitis, diagnosed using the Marseille and Cambridge Classification System (addendum II).37 * Patient suffers from chronic abdominal pain typical for pancreatitis, meet the criteria for chronic pain according ISAP (intermittent or persistent pain on a daily basis in at least 3 months)38, and consider their pain must as severe enough for medical treatment (average NRS ≥ 3). * Patient in the opioid group takes stable doses of opioids, e.g. morphine or tramadol, for the past 2 months on the day of screening. Stable dose intake is defined as a daily equivalent sum of opioid intake according medical prescription within a small deviation range as judged by the (principal) investigator. * Patient in the non-opioid group does not take any opioids for the past 2 months on the day of screening. Exclusion Criteria: * Patient used any cannabinoid (by smoking cannabis or oral intake) for at least one year on the day of screening. * Patient does not feel a pinprick test in the lower extremities, due to affected sensory input (e.g. neuropathy as a result of diabetes mellitus). * Patient has a body mass index (BMI) below 18 or above 31.2 kg/m2. * Patient suffers from serious painful conditions other than chronic pancreatitis or had any major pre-existing chronic pain syndrome. * Patient has a (history of) a significant medical disorder that, in the opinion of the investigator, may interfere with the study or may pose a risk for the patient. * Patient uses any kind of concomitant medication that, in the opinion of the investigator, may interfere with the study or may pose a risk for the patient (e.g. HIV antivirals). * Patient takes amitriptyline on a daily basis. * Patient takes more than 20 mg benzodiazepines 6 hours prior or following intake of study medication (11 hour am) according prescription.