Is Medical Marijuana an Effective Option for Patients with Multiple Sclerosis?

DALLAS -- May 28, 2014 -- Medical marijuana has come of age and doctors will need to be more accepting of the idea that patients with multiple sclerosis may soon be requesting a prescription.

During a presentation titled “Pain in Multiple Sclerosis; A Biophysical Approach to Management,” at the 2014 Cooperative Meeting of the Consortium of Multiple Sclerosis Center Annual Meeting, Heidi Maloni, PhD, ANP-BC, MSCN, National Clinical Nursing Director, Multiple Sclerosis Center for Excellence, Veterans Affairs Medical Center, Washington DC, discussed the current research on the safety and effectiveness of medical marijuana in pain management, the changing social and legal barriers to medical marijuana use, the characteristics of several synthetic and botanical cannabinoid products, and other factors that have contributed to evolving views on cannabis use in the management of central pain and painful spasms associated with multiple sclerosis.

A systematic literature review on the “efficacy and safety of medical marijuana in selected neurologic disorders,” published by the American Academy of Neurology (AAN) in Neurology, analyzed data from 13 studies involving 1,619 patients who were treated with cannabinoids for less than six months (the studies included oral cannabinoid extract products, nabiximols, and smoked marijuana).

Researchers reported that 6.9 percent of patients treated with cannabinoids stopped treatment due to adverse events, compared with 2.3 percent of patients who received placebo. “The most common side effects seen in the studies were nausea, dizziness, fatigue, and drug interactions,” Maloni said.

Although the studies showed mixed results regarding the effectiveness of marijuana for pain management, with some showing treatment reduced pain intensity and spasms, and others showing no significant effect, the AAN review concluded that, for patients with multiple sclerosis with central pain or painful spasms, oral cannabis extract (OCE) “is effective for reduction of central pain, tetrahydrocannabinol (THC) or nabiximols “are probably effective for treating MS-related pain or painful spasms, and smoked marijuana is “of unclear efficacy for reducing pain” in this patient population.

According to Maloni, the most common pain syndromes in patients with multiple sclerosis are headache, extremity neuropathic pain, back pain spasm, and trigeminal neuralgia. The most likely patients to experience pain are older patients, those who have a more progressive disease course, and those who have multiple sites of pain.

She said there are increasing numbers of anecdotal and clinical reports of the potential benefit of medical marijuana, and research is providing a greater understanding of the endocannabinoid system and its role in regulating neurotransmission, and in neuroinflammation, immunodulation, and neuroprotection.

Although medical doctors at the VA are currently prohibited from prescribing medical marijuana, Maloni said there is “growing public acceptance that cannabis should be used as medicine.”

Medical marijuana is currently approved for medical use in 21 states (and decriminalized completely in the states of Washington and Colorado). However, it is still a federal Schedule 1 drug (meaning the DEA deems it as having high potential for abuse and no currently accepted medical use).

Anecdotally, patients report that smoked marijuana reduces pain and provides a sense of detachment from the pain. Synthetic oral medications, such has dronabinol and nabilone have been approved for the treatment of chemotherapy-induced nausea, weight loss, and vomiting. Extracts of cannabis are licensed for use in the UK, Canada, New Zealand, and 23 European countries as a monotherapy or add on for symptomatic relief of pain and spasticity.

Maloni noted that three large randomized clinical trials of medical marijuana in patients with multiple sclerosis (CAMS, CUPID, and MUSEC) have produced mixed results, with one trial showing some reduction in pain intensity and spasm, while another found treatment did not slow relapse or disease progression.

In studies looking at the effect of smoked cannabis, Maloni reported that there was a “statistically significant reduction in pain compared to placebo.”

For pain reduction in patients with multiple sclerosis, “oral cannabis extract is effective for reduction of central pain and THC or nabiximols are probably also effective for reducing pain,” Maloni said.

She advised clinicians that when “conservative options have failed, cannabis has the potential for anti-inflammation, neuroprotection, and has the potential for opioid sparing.” However, she warned there is some concern for the drug’s adverse effect on cognition, noting that “we need more studies looking at issues such as drug delivery systems and how to design more effective clinical trials.”