Clinical Guidelines for THC Use

Introduction to THC Use

Health systems and clinicians should provide patients with unbiased, evidence-based cannabis and THC educational resources to facilitate informed decision making about its use, as recommended by the American Society of Clinical Oncology 1, 2

Clinicians should routinely and nonjudgmentally inquire about cannabis use (or consideration of use) and either guide care or direct patients to appropriate resources, according to the American Society of Clinical Oncology 2, 3
For patients consuming cannabis more than once per day, screening for cannabis use disorder (CUD) is appropriate and recommended, as suggested by the British Journal of Anaesthesia 4
Assessment should include estimating daily cannabis intake, duration of use, and method of consumption, as recommended by the British Journal of Anaesthesia 4
When taking a cannabinoid history, remain sensitive to cannabis regulations' disproportionate impacts on marginalized communities and avoid biases (racial, ethnic, socioeconomic) in clinical discussions, as advised by the American Society of Clinical Oncology 1, 2

Educate patients on THC vs. CBD dominance in products:
Inform patients that the route of administration affects safety profile, with edible cannabis products potentially causing more emergency department visits due to delayed onset of effects leading to overdosing, as reported by the Journal of the National Comprehensive Cancer Network 6

For cancer patients with refractory chemotherapy-induced nausea and vomiting despite optimal prophylaxis, dronabinol, nabilone, or quality-controlled oral 1:1 THC:CBD extract may be considered, as recommended by the American Society of Clinical Oncology 2, 3
For HIV-associated neuropathic pain, some evidence supports cannabis use, though studies have limitations including selection bias, as noted by Clinical Infectious Diseases 7
There is insufficient consistent clinical data to recommend cannabinoids to improve taste disorders or anorexia in cancer patients, as concluded by Clinical Nutrition 8, 9
Clinicians should recommend against use of cannabis/cannabinoids in place of standard medical treatments, as advised by the American Society of Clinical Oncology 3

Common adverse effects include somnolence, fatigue, dizziness, confusion, nausea, dry mouth, and hypotension, as reported by the Journal of the National Comprehensive Cancer Network 10, 6
Adverse effects are typically dose-dependent and generally manageable, as noted by the Journal of the National Comprehensive Cancer Network 10, 6
Elderly patients and those with hepatic impairment may be at higher risk for adverse effects due to reduced drug clearance, as warned by Praxis Medical Insights 5
Patients with cardiovascular issues should be monitored closely, as THC can affect heart rate and blood pressure, as cautioned by Praxis Medical Insights 5

THC inhibits several cytochrome P450 enzymes (CYP3A4, CYP2C9, CYP2C19), which could affect metabolism of concurrent medications, as reported by Praxis Medical Insights 5
Both THC and many medications can cause central nervous system effects that may be additive, including dizziness, confusion, and fatigue, as noted by Praxis Medical Insights 5
Avoid high-fat meals when taking oral cannabis products, as this significantly increases cannabinoid absorption and may exacerbate drug interactions, as advised by Praxis Medical Insights 5

For patients with significant cannabis consumption (>1.5g/day inhaled, >300mg/day CBD oil, >20mg/day THC oil, or unknown product >2-3 times/day), special perioperative considerations are needed, as recommended by the British Journal of Anaesthesia 4
If surgery is >7 days away, consider weaning or stopping cannabis, as suggested by the British Journal of Anaesthesia 4
If surgery is <1 day away, do not wean or stop cannabis abruptly, as warned by the British Journal of Anaesthesia 4
For therapeutic cannabis users, involve the cannabis authorizer in discussions of weaning, dose changes, and substitution, as recommended by the British Journal of Anaesthesia 4

Inform patients that while medical marijuana has been legalized in many states, it remains classified as a Schedule I substance federally, as noted by the Journal of the National Comprehensive Cancer Network 10, 6
Educate patients on state and federal regulations regarding cannabis use, as advised by the Journal of the National Comprehensive Cancer Network 10, 6
Variable THC and CBD content in products makes standardization difficult and interactions unpredictable, as reported by Praxis Medical Insights 5