Can Cannabis Be Considered a Substitute Medication for Alcohol?

Meenakshi Sabina Subbaraman

Disclosures

Alcohol Alcohol. 2014;49(3):292-298. 

In This Article

Abstract and Introduction

Abstract

Aims. Substituting cannabis for alcohol may reduce drinking and related problems among alcohol-dependent individuals. Some even recommend prescribing medical cannabis to individuals attempting to reduce drinking. The primary aim of this review is to assess whether cannabis satisfies the seven previously published criteria for substitute medications for alcohol [e.g. 'reduces alcohol-related harms'; 'is safer in overdose than alcohol'; 'should offer significant health economic benefits'; see Chick and Nutt ((2012) Substitution therapy for alcoholism: time for a reappraisal? J Psychopharmacol 26:205–12)].

Methods. Literature review.

Results. All criteria appear either satisfied or partially satisfied, though studies relying on medical cannabis patients may be limited by selection bias and/or retrospective designs. Individual-level factors, such as severity of alcohol problems, may also moderate substitution.

Conclusions. There is no clear pattern of outcomes related to cannabis substitution. Most importantly, the recommendation to prescribe alcohol-dependent individuals cannabis to help reduce drinking is premature. Future studies should use longitudinal data to better understand the consequences of cannabis substitution.

Introduction

Substitute therapies for tobacco (e.g. nicotine replacement therapy) and heroin (e.g. methadone) have been available for some time, while analogous substitutes for alcohol have been more elusive. A recent review of medication substitutes for alcohol defines seven criteria for substitution therapy (Chick and Nutt, 2012). At the same time, a growing number of studies suggest that cannabis could be considered as a substitute therapy for alcohol (Mikuriya, 2004; Charlton, 2005; Reiman, 2009). Some even suggest that medical cannabis be prescribed to individuals attempting to reduce alcohol use (Mikuriya, 2004; Charlton, 2005). In light of the recent movements toward cannabis legalization in the USA, which imply that cannabis use may become more commonplace, especially among heavy drinkers (Clements and Daryal, 2005), we need to better understand whether cannabis can substitute for alcohol among individuals who are trying to reduce drinking.

This paper assesses whether cannabis satisfies conditions for substitution therapy according to the seven criteria outlined by Chick and Nutt (2012). Please note that although the impetus is to assess the viability of cannabis as a substitute treatment or medication, the majority of the studies cited do not necessarily regard medically prescribed cannabis. However, this is not a limitation per se because naturalistic cannabis use is probably more generalizable to 'real-life' conditions.

Criteria for Substitution Treatment and Common Substitution Medications

Chick and Nutt (2012) recent review of medication substitutes outlined the following criteria for any substitution treatment:

  1. It should reduce alcohol use and related harms.

  2. It should ideally be free of harms, or at least less harmful than alcohol.

  3. Misuse should be less than that of alcohol.

  4. It should be shown that it can substitute for alcohol and not be used along with alcohol.

  5. It should be safer in overdose than alcohol.

  6. It should ideally not potentiate the effects of alcohol especially if either drug is taken in overdose.

  7. It should offer significant health economic benefits.

Benzodiazepines and γ-aminobutyric acid (GABA) agonists have been considered the most promising substitutes for alcohol (Chick and Nutt, 2012). However, results from a series of studies by Zack et al. implied that benzodiazepines may prolong the risk of relapse (Zack et al., 1999, 2006; Poulos and Zack, 2004). Furthermore, the American Psychiatric Association Task Force has cautioned against prescribing benzodiazepines to patients with a history of substance abuse or dependence because of their high-addiction potential.

Drugs such as sodium oxybate and baclofen also affect the GABAergic system and therefore have some pharmacological properties similar to alcohol. GABA agonists like baclofen may suppress cravings, reduce drinking and improve liver function (Addolorato et al., 2002, 2005, 2007a, b), but also increase alcohol-induced sedation and can severely impact daily functioning if not carefully titrated. Sodium oxybate, a drug similar to the street drug γ-hydroxybutyric acid (GHB), has also met controversy due to its addiction potential (Chick and Nutt, 2012). Other GABA-acting drugs (e.g. clomethiazole) were used in the 1970–1980s and found to cause less liver damage than alcohol; however, these drugs can be fatal when mixed with alcohol (Chick and Nutt, 2012).

Although benzodiazepines and GABA agonists may be medically acceptable substitutes for alcohol, they can have unpleasant side effects for many people. In addition, these drugs can lead to dependence and health risks if alcohol is ingested simultaneously (US Food and Drug Administration, 2013). Based on these premises, Charlton (2005) suggested that cannabis might be 'a safer and less anti-social substitute' for drinking. Charlton claimed that most people use alcohol to achieve certain psychological effects, and that they will choose equally effective substitutes as long as they are available, legal and socially acceptable. Charlton stated that alcohol policy should aim to reduce related medical and social harms and that 'lifestyle drug substitution' or substituting safer but equally effective agents, could be one way to reduce harms (Charlton, 2005).

Charlton admitted that cannabis substitution may be a radical idea. But whether radical or not: does cannabis satisfy the seven criteria for substitution therapies?

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