Can Tetrahydrocannabinol (THC) cause abdominal pain in individuals, particularly those with a history of gastrointestinal disorders such as irritable bowel syndrome?

Can THC Cause Abdominal Pain?

Yes, THC can paradoxically cause severe abdominal pain through Cannabinoid Hyperemesis Syndrome (CHS), a condition that develops in chronic cannabis users and presents with cyclic vomiting and abdominal pain that resolves only with cannabis cessation. 1, 2

Understanding the Paradox

While cannabis has historically been used to treat abdominal pain and some patients report symptomatic relief, chronic THC exposure fundamentally dysregulates the endocannabinoid system, leading to a syndrome characterized by the very symptoms it was intended to treat:

• CHS should be suspected in any chronic cannabis user presenting with cyclic vomiting and abdominal pain, according to the American Gastroenterological Association 1
• Key diagnostic features include recurrent episodes of nausea, vomiting, and abdominal pain in patients with chronic cannabis use, compulsive hot bathing or showering that provides symptom relief, and resolution of symptoms with cannabis cessation 1
• The pathognomonic hot water bathing behavior occurs in 44% of CHS patients and is highly specific for this diagnosis 2

Mechanism of THC-Induced Abdominal Pain

The endocannabinoid system's control over emesis becomes dysregulated in CHS through several mechanisms:

• CB1 receptors are densely distributed in the dorsal vagal complex, a critical area for controlling emesis 2
• Chronic cannabis use leads to loss of negative feedback on the hypothalamic-pituitary-adrenal axis, resulting in increased vagal nerve discharges that contribute to vomiting 2
• Altered gastric motility and emptying occur through peripheral CB1 receptor activation 2
• Modern cannabis products contain dramatically higher THC concentrations than historical products, increasing the risk of CHS 2

Critical Diagnostic Considerations

CHS is frequently underdiagnosed or misdiagnosed due to limited clinician awareness, leading to extensive unnecessary testing 2. When evaluating a patient with abdominal pain and cannabis use history:

• Look specifically for stereotypical episodic vomiting (at least 3 episodes annually) with acute onset and duration less than 1 week 2
• Ask directly about compulsive hot water bathing behavior for symptom relief—this is pathognomonic 1, 2
• The total THC dose and duration of use are the critical factors, not the method of consumption (smoking, vaping, or edibles all carry equal risk) 2
• Rule out life-threatening conditions first (acute abdomen, bowel obstruction, mesenteric ischemia, pancreatitis) before attributing symptoms solely to CHS 2

Acute Management of THC-Induced Abdominal Pain

The American Gastroenterological Association recommends avoiding opioids, as they worsen nausea and carry high addiction risk, and considering butyrophenones such as haloperidol or droperidol for suspected CHS 1, 2:

• Butyrophenones have superior efficacy in reducing hospital length of stay by nearly 50% (6.7 vs 13.9 hours, p=0.014) 2
• Topical capsaicin (0.1% cream) applied to the abdomen may provide symptom relief through activation of transient receptor potential vanilloid type 1 receptors 1, 2
• Benzodiazepines can be considered for their sedating and anxiolytic effects, which address the stress-mediated component of CHS 2
• Supportive care with intravenous fluids and electrolyte replacement is essential 1

Definitive Treatment

Cannabis cessation is the only definitive treatment for CHS and should be strongly recommended as the primary intervention, according to the American Gastroenterological Association 1, 2:

• Provide counseling to achieve marijuana cessation as the primary intervention 1
• Tricyclic antidepressants such as amitriptyline are the mainstay of preventive therapy for long-term management, starting at 25 mg at bedtime and titrating weekly to reach a minimal effective dose of 75-100 mg 1, 3

THC for Abdominal Pain Treatment: The Evidence Gap

Despite widespread use, the evidence does not support THC as an effective treatment for chronic abdominal pain:

• 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
• A phase 2 placebo-controlled trial found no difference between THC tablets and placebo in reducing pain measures in patients with chronic abdominal pain (VAS mean scores decreased by 1.6 points in THC group vs 1.9 points in placebo group, p=0.901) 4
• While animal and human studies suggest cannabis may have modulatory effects on the endocannabinoid system in the GI tract, clinical efficacy for various GI disorders remains unclear 5, 6

Special Populations: IBS and Functional GI Disorders

For patients with irritable bowel syndrome or functional gastrointestinal disorders:

• The 2021 AGA Clinical Practice Update explicitly states it does not discuss the use of complementary or alternative therapies such as marijuana for management of chronic gastrointestinal pain in disorders of gut-brain interaction 7
• The British Society of Gastroenterology guidelines on IBS management mention cannabinoid type-2 receptor agonists (olorinab) as a novel approach under investigation, but do not recommend THC itself 7
• One retrospective study suggested cannabis users with IBS had shorter hospital stays and less healthcare utilization, but this does not establish causation or recommend THC as treatment 8

Critical Pitfall to Avoid

Do not prescribe or recommend THC for chronic abdominal pain management. The risk of developing CHS, combined with lack of efficacy evidence and potential for dependency, makes this an inappropriate therapeutic choice. Instead, follow evidence-based guidelines recommending tricyclic antidepressants, SNRIs, gut-directed hypnotherapy, and cognitive behavioral therapy for chronic functional abdominal pain 7, 1, 3.