• Primary endpoint gastric accommodation [ Time Frame: 4 Weeks ]
  Fasting gastric and accommodation volumes (mL) measured by SPECT
• Primary Endpoint satiation [ Time Frame: 4 weeks ]
  Volume to fullness (VTF, mL) on satiation test
• Primary endpoint Gastric emptying [ Time Frame: 4 weeks ]
  Gastric emptying T1/2 of solids on scintigraphy, minutes
• Primary endpoint Gastroparesis symptoms [ Time Frame: Daily diary over 4 weeks ]
  Average weekly gastroparesis cardinal symptom index-daily diary score on treatment in patients with gastroparesis evaluating 6 symptoms (nausea, abdominal distension, bloating, early satiety, vomiting, and abdominal pain) on a 5 point scale ranging from none to very severe
• Primary endpoint functional dyspepsia symptoms [ Time Frame: Every 2 weeks ]
  Postprandial distress score on Nepean Dyspepsia Index (one of 10 items each scored on 5 point scale ranging from "not at all" to "extremely" in patients with functional dyspepsia

• Secondary Endpoint Gastric emptying [ Time Frame: 4 Weeks ]
  Gastric emptying of solids at 2 hours and 4 hours on scintigraphy, %
• Secondary Endpoint Symptom scores during gastric emptying test [ Time Frame: over 4 hours at 4 weeks ]
  Aggregate symptoms and individual symptom scores under the curve during the 4 hours after the standard meal during the gastric emptying test, measured on 0-100 mm visual; analog scale
• Secondary Endpoint Satiation [ Time Frame: over 2 hour test at week 4 ]
  Maximum tolerated volume (mL) and aggregate symptoms (nausea, fullness, bloating, pain on 0-100mm visual analog scale), scored 30min after MTV on satiation
• Secondary Endpoint Gastroparesis symptoms [ Time Frame: 4 weeks ]
  On weekly gastroparesis cardinal symptom index-daily diary, Individual subscales of GCSI-DD (3 subscales: nausea/vomiting, postprandial fullness/early satiety, and bloating) score in patients with gastroparesis evaluated by a 5 point scale ranging from none to very severe
• Secondary Endpoint: Overall dyspepsia score [ Time Frame: Every 2 weeks ]
  Overall Nepean Dyspepsia Index (NDI) score in functional dyspepsia based on 10 items each scored on 5 point scale ranging from "not at all" to "extremely"
• Secondary Endpoint: Pain score in dyspepsia [ Time Frame: Every 2 weeks ]
  Pain based on Nepean Dyspepsia Index (NDI) score based on 5 point scale ranging from "not at all" to "extremely"
• Secondary Endpoint: Adequate relief response in functional dyspepsia [ Time Frame: 4 weeks ]
  Single question on adequate relief answered "yes" or "no"
• Secondary endpoint: Daily score in functional dyspepsia [ Time Frame: daily for 4 weeks ]
  Daily Symptom score of upper abdominal pain, nausea and bloating or distension based on 5 point scale (ranging from none to severe) in patients with functional dyspepsia

• Gastroparesis
• Dyspepsia

• Drug: Cannabidiol

  Cannabidiol and the matching placebo solution (excipients alone) will be provided in identical 100ml amber glass bottles. At the end of the treatment period, the treatment solutions will be tapered (10% volume each day) over 10 days.

  In accordance with Food and Drug Administration guidance, prior to starting treatment and at end of 1 month treatment, we shall obtain serum transaminases (alanine and aspartate) and total bilirubin levels. These tests will also be performed if patient develops clinical signs or symptoms suggestive of hepatic dysfunction (e.g., unexplained nausea, vomiting, right upper quadrant abdominal pain, fatigue, anorexia, or jaundice and/or dark urine); if such features develop the treatment will be interrupted or discontinued.

• Other: placebo

  Cannabidiol and the matching placebo solution (excipients alone) will be provided in identical 100ml amber glass bottles. At the end of the treatment period, the treatment solutions will be tapered (10% volume each day) over 10 days.

  In accordance with Food and Drug Administration guidance, prior to starting treatment and at end of 1 month treatment, we shall obtain serum transaminases (alanine and aspartate) and total bilirubin levels. These tests will also be performed if patient develops clinical signs or symptoms suggestive of hepatic dysfunction (e.g., unexplained nausea, vomiting, right upper quadrant abdominal pain, fatigue, anorexia, or jaundice and/or dark urine); if such features develop the treatment will be interrupted or discontinued.

• Active Comparator: Pharmacodynamics and clinical effects of cannabidiol

  Cannabidiol will be administered orally twice daily in equally divided doses starting at 2.5mg/kg per day and increasing by 2.5 to 5.0mg/kg every other day until the target dose of 20mg/kg is reached.

  Cannabidiol and the matching placebo solution (excipients alone) will be provided in identical 100ml amber glass bottles. At the end of the treatment period, the treatment solutions will be tapered (10% volume each day) over 10 days.

  Intervention: Drug: Cannabidiol
• Placebo Comparator: pharmacodynamics and clinical effects of placebo

  Placebo will be administered orally twice daily in equally divided doses starting at 2.5mg/kg per day and increasing by 2.5 to 5.0mg/kg every other day until the target dose of 20mg/kg is reached.

  Cannabidiol and the matching placebo solution (excipients alone) will be provided in identical 100ml amber glass bottles. At the end of the treatment period, the treatment solutions will be tapered (10% volume each day) over 10 days.

  Intervention: Other: placebo

Inclusion Criteria:

• Patients with gastroparesis or functional dyspepsia
• Age 18-70 years
• Patients will be identified from among Mayo Clinic patients.

• Patients will have symptoms consistent with gastroparesis based on a national guideline (2) for gastroparesis (symptoms PLUS delayed gastric emptying of solids). Patients with Rome IV criteria for postprandial distress syndrome (a subset of functional dyspepsia) (35) will be selected based on gastric emptying of solids which is NOT delayed, in addition to standard FD criteria:

  • Symptoms fulfilled for the last 3 months with onset greater than 6 months before diagnosis:
  • One or more symptoms being bothersome: postprandial fullness, early satiation, epigastric pain or burning
  • Must include one or both of the following at least 3 days per week: bothersome postprandial fullness (i.e., severe enough to impact on usual activities) or bothersome early satiation (i.e., severe enough to prevent finishing a regular-size meal)
  • No evidence of organic, systemic, or metabolic disease to explain the symptoms on routine investigations.
  • Participants will have previously undergone test of gastric emptying of solids using the standardized Mayo Clinic scintigraphic method
• Ability to provide informed consent
• Absence of other diseases (structural or metabolic) which could interfere with interpretation of the study results
• Body mass index of 18-35 kg/m2
• Several medication classes, particularly those affecting gastrointestinal transit or motor functions, will be excluded, including GLP-1 receptor or amylin agonists in patients with diabetes mellitus. Stable doses of thyroid replacement, estrogen replacement, low-dose aspirin for cardioprotection, and birth control (but with adequate backup contraception, as drug interactions with birth control have not been conducted for secretin PAM) are

Exclusion Criteria:

• Patients with current H. pylori infection will be excluded.
• Pregnancy or lactation
• Rapid metabolizers for CYP3A4 or CYP2C19 [estimated prevalence of 17% and 18% respectively
• based on literature review (36)] will be excluded since this could impact assessment of effects of cannabidiol
• Patients with abnormal baseline liver transaminases (any value above UNL), since up to 3-fold, dose-related elevations of liver transaminases (ALT and/or AST) occur in 13% of treated patients (vs. 1% placebo);
• Hypersensitivity to cannabidiol or any of the ingredients in EPIDIOLEX
• Concomitant use of valproate, CNS depressants and alcohol, other hepatotoxic drugs