Background: Multiple sclerosis (MS), which commonly affects the young population, is a demyelinating disease of immunological origin. MS-related pain occurs either directly as a result of inflammation of neural tissue, or as a result of muscle spasms and spasticity exerting pressure on the musculoskeletal system. Cannabis has proven ability to manage pain associated with MS. Central pain is a chronic syndrome that occurs commonly in multiple sclerosis patients, with a frequency of patients affected ranging from 36% to 82%. Central pain is one of the most common symptoms that affect the quality of life of MS patients only second to fatigue.
Objective: To systematically evaluate the literature comparing the analgesic effects of pharmacological treatments for Trigeminal Neuralgia in patients with MS.
Methods: The research was conducted using a search strategy to identify randomized clinical trials on pharmacological treatments of central pain in MS. The clinical trials were found in the following databases: Pub med (1965-2014), Cochrane (2000-2014), Lilacs (2000-2014), Proquest (2000-2014), Medline (1965- 2014) with latest search date December 2013. Selection criteria: Randomized controlled trials with subjective pain assessment using the Jadad assessment score including a score greater than three for selection criteria.
Results: Seven studies met inclusion criteria and were analyzed. Six of them compared cannabinoids against placebo. One compared the anticonvulsant lamotrigine versus placebo. Randomized studies of cannabinoids against placebo found a decrease of three points in the Jadad pain scale with treatments using Dronabinol (cannabinoids). Patients reported mild adverse effects including: dizziness, drowsiness, dry eyes and impaired balance. These symptoms did not compromise the quality of life of patients. The overall conclusive treatment effect of central pain in MSwith Lamotrigine was not significant (p=0.67).
Conclusions: Most of the prospective clinical trials evaluating the pharmacologic treatment of central pain in MS, involved trials using cannabinoids. Cannabis reduces pain in MS sufferers by directly working to reduce immune response and resultant inflammation. There appears to be a statistically significant analgesic effect in patients with MS-related central pain. Clinical trials with larger samples are needed in order to provide stronger evidence regarding the safety and effectiveness of therapeutic doses of cannabinoids. There is a lack of well-designed studies aimed at the other drug therapies for MS-related central pain.
Andres M Alvarez