Researchers confirmed that Sativex spray is beneficial in alleviating pain in patients with multiple sclerosis (MS), and also improved their pain sensitivity to cold temperatures.
The study reporting the findings, “Pain Modulation after Oromucosal Cannabinoid Spray (SATIVEX) in Patients with Multiple Sclerosis: A Study with Quantitative Sensory Testing and Laser-Evoked Potentials,” was published in the journal Medicines.
Pain is one of the most debilitating symptoms of MS; it affects 29 to 86 percent of patients. It is associated with disability, distress, and negatively influences their quality of life.
Sativex (nabiximols) is a oromucosal spray containing equal amounts of two cannabinoids: delta-9-tetrahydrocannabinol (THC) and cannabidiol (CBD). The product is marketed by GW Pharmaceuticals.
In the study, researchers in Italy tested the ability of Sativex to alleviate neuropathic (nerve-related) and nociceptive pain (muscle- and soft tissue-related) in MS patients.
Nineteen MS patients (18 to 65 years old) with chronic pain and spasticity participated in the study. All patients received Sativex (mean of 6.9 puffs per day) for one month, and pain levels were assessed before and after treatment.
Researchers used a numerical rating scale (NRS) to quantify pain in the range of 0 to 10. The higher the NRS, the worse the pain. Pain was further assessed through a neurophysiological technique called laser-evoked potentials (LEP). In LEP, fine lasers are used to apply heat on the skin, and the response of sensory fibers that carry pain information to the brain are recorded.
Pain-related heat and cold response was measured using a psychophysiological technique called quantitative sensory testing (QST). QST assesses the response to painful stimuli (hyperalgesia) and the response to a stimulus that doesn’t invoke pain (allodynia). Patients were asked to indicate when they detected heat/cold, and for how long they could bear the heat/cold to determine pain thresholds.
Researchers compared the results with data from 20 healthy volunteers, sex- and age-matched to the patient group analyzed.
The main finding of the study was that 74% of the patients (14 patients) reported a 20% reduction in pain after Sativex treatment, indicated by a significant reduction in NRS scores (from 6.61 to 3.55 after treatment).
Compared to healthy study participants, MS patients have decreased upper-limb and lower-limb pain response in LEP, suggesting they have a higher loss of pain and temperature sensations in their limbs. However, no significant change in LEP was observed in patients after Sativex treatment.
Nonetheless, Sativex treatment was found to improve the cold pain threshold in MS patients significantly through the QST test. The perception of abnormal cold temperatures was reduced from 39.5% before treatment to 28.9% after Sativex therapy in the feet, and from 35.5% to 25% in the hands.
Since pain was reduced in response to temperature, the researchers hypothesized that Sativex may work via the transient receptor potential (TRP) channels — the cellular sensors for cold and heat stimuli.
“In summary, our study further corroborates evidence for the effectiveness of Sativex in reducing pain in MS patients. Furthermore, our findings suggest a possible direct effect of cannabinoids on TRP channels by modulating or desensitizing cold-channel functions” the team concluded.