Managing Abdominal Pain in Marijuana Users
The primary consideration when evaluating abdominal pain in marijuana users is to determine whether the patient has cannabinoid hyperemesis syndrome (CHS), which requires cannabis cessation as definitive treatment, while avoiding opioids and unnecessary investigations. 1
Initial Diagnostic Approach
Screen for Cannabinoid Hyperemesis Syndrome (CHS)
CHS should be suspected in any chronic cannabis user presenting with cyclic vomiting and abdominal pain. 1 Key diagnostic features include:
- Recurrent episodes of nausea, vomiting, and abdominal pain in patients with chronic cannabis use (typically developing within 1-5 years of regular use) 2
- Compulsive hot bathing or showering that provides symptom relief—this is a pathognomonic feature 1, 2
- Resolution of symptoms with cannabis cessation 1
- Symptoms typically occur in three phases: prodromal (early morning nausea, abdominal discomfort), hyperemetic (incapacitating nausea and profuse vomiting), and recovery 2
Quantify Cannabis Consumption
Document specific usage patterns to guide management 1, 3:
- Amount consumed per day (grams of smoked cannabis, mg of CBD/THC oil)
- Frequency of use (times per day/week)
- Method of consumption (smoked, edible, oil)
- CBD to THC ratio if known
- Duration of regular use
Rule Out Alternative Diagnoses
In the emergency setting, immediately exclude life-threatening conditions including acute abdomen, bowel obstruction, mesenteric ischemia, pancreatitis, and myocardial infarction 1. Cannabis use has been associated with acute pancreatitis in case reports, though this is rare 4.
In the outpatient setting after structural abnormalities are excluded, consider rumination syndrome, gastroparesis, cyclic vomiting syndrome (non-cannabis related), pregnancy, migraine, and functional chronic nausea and vomiting syndrome 1.
Acute Management
For Suspected CHS
Avoid opioids, as they worsen nausea and carry high addiction risk 1. Standard antiemetics are generally poorly effective 1.
Consider butyrophenones (haloperidol or droperidol) as they have shown some success in CHS 1.
Topical capsaicin (0.1% cream) may provide symptom relief through activation of transient receptor potential vanilloid type 1 receptors 1.
Supportive care with intravenous fluids and electrolyte replacement is essential 1.
For Cannabis Withdrawal Syndrome (CWS)
If the patient has been abstinent from cannabis for 48+ hours and develops nausea and abdominal pain, consider CWS 1:
- Supportive care is the mainstay
- Gabapentin, nabilone, nabiximols, or dronabinol may be beneficial but require expert guidance 1
- Symptoms typically peak in the first week and last 1-2 weeks after cessation 1
Long-Term Management
Cannabis Cessation is Essential
The definitive treatment for CHS is complete cannabis abstinence 1. However, recidivism rates are high 1.
Provide counseling to achieve marijuana cessation as the primary intervention 1.
Consider tricyclic antidepressants (amitriptyline) for long-term symptom management 1:
- Start at 25 mg at bedtime
- Titrate weekly to reach minimal effective dose of 75-100 mg
- Monitor for efficacy and adverse effects
Address Psychiatric Comorbidities
Co-management with psychology or psychiatry is recommended for patients with lack of response to standard therapies or extensive psychiatric comorbidity 1. Anxiety and depression are very common associated conditions in CHS patients 1.
Combining evidence-based psychosocial interventions with pharmacology may be necessary for successful long-term management 1.
Special Considerations
Cannabis Use Without CHS
For patients using cannabis who do not have CHS, the Canadian Association of Gastroenterology recommends against using marijuana to treat abdominal pain in conditions like Crohn's disease, as evidence shows it does not induce symptomatic remission 1.
Research suggests cannabis users with inflammatory bowel disease report more abdominal pain, gas, tenesmus, and arthralgias, but do not demonstrate more frequent active disease or complications, suggesting extraintestinal factors influence their symptoms 5. This highlights the importance of evaluating for non-luminal contributors to symptom burden.
Perioperative Context
Heavy cannabis users (>1.5 g/day smoked, >300 mg/day CBD oil, or >20 mg/day THC oil) may require higher analgesic doses postoperatively due to tolerance 1.
Cannabis use is not a contraindication to NSAIDs, opioids, local anesthetics, ketamine, gabapentin/pregabalin, dexmedetomidine, or acetaminophen 1.
Common Pitfalls to Avoid
- Do not prescribe opioids for CHS-related abdominal pain, as they worsen nausea and carry addiction risk 1
- Do not perform unnecessary invasive investigations once CHS is diagnosed—it is a clinical diagnosis 1, 2
- Do not ignore the compulsive hot bathing behavior, as this is pathognomonic for CHS 1, 2
- Do not assume all abdominal pain in cannabis users is CHS—maintain vigilance for other serious pathology, especially in severe or refractory cases 1
- Avoid abrupt cessation in heavy users without support, as withdrawal symptoms can be significant 1, 3