Rationale for cannabis-based interventions in the opioid overdose crisis
Harm Reduction Journal, 2017, 14, 58
Doi : 10.1186/s12954-017-0183-9
Background : North America is currently in the grips of a crisis rooted in the use of licit and illicit opioid-based analgesics. Drug overdose is the leading cause of accidental death in Canada and the US, and the growing toll of opioid-related morbidity and mortality requires a diversity of novel therapeutic and harm reduction-based interventions. Research suggests that increasing adult access to both medical and recreational cannabis has significant positive impacts on public health and safety as a result of substitution effect. Observational and epidemiological studies have found that medical cannabis programs are associated with a reduction in the use of opioids and associated morbidity and mortality.
Aims and Methods : This paper presents an evidence-based rationale for cannabis-based interventions in the opioid overdose crisis informed by research on substitution effect, proposing three important windows of opportunity for cannabis for therapeutic purposes (CTP) to play a role in reducing opioid use and interrupting the cycle towards opioid use disorder: 1) prior to opioid introduction in the treatment of chronic pain; 2) as an opioid reduction strategy for those patients already using opioids; and 3) as an adjunct therapy to methadone or suboxone treatment in order to increase treatment success rates. The commentary explores potential obstacles and limitations to these proposed interventions, and as well as strategies to monitor their impact on public health and safety.
Conclusion : The growing body of research supporting the medical use of cannabis as an adjunct or substitute for opioids creates an evidence-based rationale for governments, health care providers, and academic researchers to consider the implementation and assessment of cannabis-based interventions in the opioid crisis.
Keywords : Addiction, Opioids, Cannabis, Marijuana, Substitution, Harm reduction
North America is currently in the grips of a crisis rooted in the use of licit and illicit opioid-based analgesics. Drug overdose is the leading cause of accidental death in Canada and the US, with many of these deaths amongst people affected by opioid use disorder. In 2015, there were 52,404 drug overdose deaths in the US, including 33,091 (63.1%) overdose deaths related to opioids . In British Columbia, despite the declaration of a public health emergency in 2016 and the scale-up of public health-based efforts such as the opening of emergency overdose prevention sites in many high-use jurisdictions, use and overdose rates continue to rise. On April 26th British Columbia reported 130 opioid-related overdoses emergency calls in a single day,1 and in March 2017, 120 individuals died of drug overdoses.2 In light of the growing toll of opioid-based morbidity and mortality, this crisis requires a diversity of novel therapeutic and harm reduction-based interventions, and evidence suggests cannabis may have a role to play in reducing some of these harms.
Substitution effect is a theory originating from behavioral economics that examines how the availability of one good can impact and influence the use of other goods. In regards to substance use, Hursh et al. (2005) suggest that “pharmacological therapies for the treatment of drug abuse can also be conceptualized as alternative commodities that either substitute for illicit drug use (e.g., agonist therapy) or reduce the potency of illicit drugs directly (e.g., narcotic antagonist therapy)” . Common examples of such harm reduction-focused substitution effect include the use of e-cigs or nicotine patches as alternatives to cigarettes, or methadone/suboxone treatment as an alternative to heroin. This paper presents an evidence-based rationale for cannabis-based interventions in the opioid overdose crisis informed by research on substitution effect and the principles of harm reduction.
There is a growing amount of evidence that increasing adult access to both medical and recreational cannabis has significant positive impacts on public health and safety, largely as a result of substitution effect. Population-level research describes how the introduction of regimes for legal access to cannabis (e.g., medical and/or recreational) in some US states has preceded reductions in homicides and violent crime , suicides , and automobile-related fatalities [5–7], all potentially related to subsequent declines in alcohol use. Additionally, epidemiological research has found that medical cannabis programs are associated with a reduction in the use of opioids and associated morbidity and mortality. Bachhuber et al.  report that U.S. states with medical cannabis laws had a 24.8% lower mean annual opioid overdose mortality rate compared to states without medical cannabis laws, and a 2016 study found that the number of Medicare prescriptions to seniors in medical cannabis states dropped for drugs that treat pain, depression, anxiety, nausea, psychoses, seizures and sleep disorders . For pain, the annual number of annual doses prescribed per physician fell by 1826 doses.
More recently, a retrospective survey of Michigan patients concluded that medical cannabis use was associated with a 64% decrease in opioid use (n = 118), decreased side effects of medications, and an improved quality of life , and a large survey of 2897 medical cannabis patients in California found that 30% of the sample (n = 841) reported using opioid-based pain medications, 97% of which “strongly agreed/agreed” that they were able to decrease their opioid use when using medical cannabis .
A 2015 cross sectional survey of patients in Canada’s national medical cannabis system found that 63% of respondents reported substituting cannabis for prescription drugs (n = 166), with 32% of the pharmaceuticals being substituted for being prescription opioids (n = 80).
The primary reasons cited by patients for this substitution were “less adverse side effect” (39%, n = 68); “cannabis is safer” (27%, n = 48), and “better symptom management” (16%, n = 28) . This evidence is consistent with information from Veteran’s Affairs Canada (VAC) showing that a recent significant increase in the use of medical cannabis by Canadian veterans was paralleled by a reduction of approximately 30% in the number of prescriptions for benzodiazepines, and a 16% decrease in the use of opioids .