Is marijuana safe and effective as medicine?
The potential medicinal properties of marijuana and its components have been the subject of research and heated debate for decades. THC itself has proven medical benefits in particular formulations. The U.S. Food and Drug Administration has approved THC-based medications, dronabinol (Marinol®) and nabilone (Cesamet®), prescribed in pill form for the treatment of nausea in patients undergoing cancer chemotherapy and to stimulate appetite in patients with wasting syndrome due to AIDS.
In addition, several other marijuana-based medications have been approved or are undergoing clinical trials. Nabiximols (Sativex®), a mouth spray that is currently available in the United Kingdom, Canada, and several European countries for treating the spasticity and neuropathic pain that may accompany multiple sclerosis, combines THC with another chemical found in marijuana called cannabidiol (CBD). CBD does not have the rewarding properties of THC, and anecdotal reports indicate it may have promise for the treatment of seizure disorders, among other conditions. A CBD-based liquid medication called Epidiolex is currently being tested in the United States for the treatment of two forms of severe childhood epilepsy, Dravet syndrome and Lennox-Gastaut syndrome.
Researchers generally consider medications like these, which use purified chemicals derived from or based on those in the marijuana plant, to be more promising therapeutically than use of the whole marijuana plant or its crude extracts. Development of drugs from botanicals such as the marijuana plant poses numerous challenges. Botanicals may contain hundreds of unknown, active chemicals, and it can be difficult to develop a product with accurate and consistent doses of these chemicals. Use of marijuana as medicine also poses other problems such as the adverse health effects of smoking and THC-induced cognitive impairment. Nevertheless, a growing number of states have legalized dispensing of marijuana or its extracts to people with a range of medical conditions.
An additional concern with "medical marijuana" is that little is known about the long-term impact of its use by people with health- and/or age-related vulnerabilities—such as older adults or people with cancer, AIDS, cardiovascular disease, multiple sclerosis, or other neurodegenerative diseases. Further research will be needed to determine whether people whose health has been compromised by disease or its treatment (e.g., chemotherapy) are at greater risk for adverse health outcomes from marijuana use.
Medical Marijuana Legalization and Prescription Opioid Use Outcomes
NIDA funded two recent studies that explored the relationship between marijuana legalization and adverse outcomes associated with prescription opioids. The first found an association between medical marijuana legalization and a reduction in overdose deaths from opioid pain relievers, an effect that strengthened in each year following the implementation of legislation.79 The population-based nature of this study does not establish a causal relationship or give evidence for changes in pain patient behavior.80,81
The second NIDA-funded study, a more detailed analysis by the RAND Corporation, showed that legally protected access to medical marijuana dispensaries is associated with lower levels of opioid prescribing, lower self-report of nonmedical prescription opioid use, lower treatment admissions for prescription opioid use disorders, and reduction in prescription opioid overdose deaths.82 Notably, the reduction in deaths was present only in states with dispensaries (not just medical marijuana laws) and was greater in states with active dispensaries.
Research into the effects of cannabis on opioid use in pain patients is limited, but data suggest that medical cannabis treatment may reduce the dose of opioids required for pain relief.83,84 In addition to its research portfolio on the roles of the cannabinoid and opioid systems in pain, NIDA is funding additional studies that will provide data relating to medical marijuana and opioids:
- effects of access to medical marijuana on substance use, including nonmedical use of prescription opioids (project numbers DA031816-05, DA039293-01A1, DA037341-02, DA032693-04)
- mental and physical functioning of a cohort of pain patients seeking medical marijuana treatment (DA033397-03)
- the impact of medical marijuana policies on health outcomes (DA034067-03)
Another recent study analyzed Medicare prescription drug coverage data and found that availability of medical marijuana significantly reduced prescribing of medications used for conditions that medical marijuana can treat, including opioids for pain.85 Overall savings for all prescription drugs were estimated to be $165.2 million in 2013.
Though none of these studies are definitive, they cumulatively suggest that medical marijuana products may have a role in reducing the use of opioids needed to control pain. More research is needed to investigate this possibility.
Cite this article
NIDA. (2018, February 12). Marijuana. Retrieved from https://www.drugabuse.gov/publications/research-reports/marijuana