Domain 1: When to consider introducing cannabinoids in patients with chronic pain taking opioids
The first domain asked questions about patient factors that may influence the suitability of a patient for treatment with cannabinoids. The key consensus findings are:
1) If a patient has a history of psychosis, is pregnant or breastfeeding, or has had an adverse reaction to cannabinoids, cannabinoids should be avoided. Although, when considering a patient with a history of psychosis, THC appears to be the more significant causal agent and CBD may in fact reduce psychosis.45,46 Physicians may consider medical cannabis in a patient: taking opioids at any morphine equivalent dose (MED), not reaching chronic pain goals, experiencing opioid-related adverse effects, and/or, displaying risk factors for opioid-related harm. It is important to note that this consensus initiative does not aim to suggest that all patients taking opioids should reduce their opioids. In a recent commentary, the Centre for Disease Control guidelines for opioid tapering were clarified to highlight that clinicians should avoid increasing the opioid dosage to ≥ 90 MED, but not necessarily discontinue opioids in patients on a high dose.47 Dialogue and shared-decision making with the patient and carefully evaluating the benefits and risks associated with tapering and discontinuation of opioids is strongly encouraged. In addition, before the introduction of any additional pharmaceutical intervention, evidence-based psychological and physical therapy interventions to reduce opioid use should be attempted and maximized.48,49
2) There was consensus that no age restrictions were recommended for CBD or THC use. With respect to CBD, the group quickly reached consensus as high doses of CBD have been shown to be safe in children, albeit in a patient population dissimilar to typical patients with chronic pain.50,51 Conversely, there was debate surrounding the minimum age recommendation for THC. When using THC, careful consideration in the younger population should be made as the nervous system is not fully developed until 25 years of age.52However, the consensus summit participants debated that if a young patient is already on opioids it did not seem rational to withhold cannabinoid therapy until they turn a specific age. Similarly, although there was no maximum age agreed to, careful consideration must be given when considering cannabinoids to the elderly, while also recognizing that the elderly are particularly susceptible to the adverse effects of opioids.