Abstract
Background. Neuropathic pain is a debilitating pain syndrome that underlies phantom pain, in particular - due to combat trauma. Phantom neuropathic pain affects 45-85% of patients who have undergone limb amputations or spinal cord injury. Less than half of patients manage to achieve significant pain relief with pregabalin, gabapentin, duloxetine and tricyclic antidepressants. Taking opioid drugs is accompanied by many undesirable side effects. Aim: to review current data on the possibility of using cannabinoids in the treatment of patients with chronic neuropathic pain. Materials and methods. Analysis of data presented in PubMed, using the keywords “neuropathic pain”, “cannabinoids”, “efficacy”, “safety”. Results. The bioavailability of the main psychoactive component of marijuana, delta-9-tetrahydrocannabinol (THC), orally is only 6% (due to intensive presystemic metabolism in the intestinal wall and the influence of drug transporters P-gp and BCRP), while when smoked it is 25%, and when inhaled it is 10–35%. The pharmacokinetics of another significant component, cannabidiol (CBD), do not differ significantly. Therefore, when cannabis is inhaled, acute pain is relieved, while orally it provides a long-lasting effect, which is advisable to use for constant pain. The THC/CBD ratio in the drug and a gradual increase in its dose are of great importance. An anonymous survey of 227 patients with traumatic spinal cord injury showed that in 87.9%, cannabis reduced the intensity of neuropathic pain by more than 30%. The majority of participants (83.3%) indicated that they had replaced their analgesic medications (including opioids and gabapentinoids) with cannabis. The number of patients needed to treat to achieve a 30% pain reduction is 2.9-3.2 when using medium or low doses of cannabis. Conclusion. Medical cannabis preparations have proven their effectiveness for the correction of neuropathic pain, their effectiveness corresponds to the effectiveness of opioids, while the risk of adverse reactions is significantly lower. It is necessary to take into account the features of the clinical course of the disease and the pharmacokinetics of cannabinoids to choose the route of administration, the initial dose and the rate of dose titration to increase the effectiveness of therapy and minimize the risk of side effects