Mecobalamin (Methylcobalamin)

Sawangjit R, et al. The Journal of Alternative and Complementary Medicine, 2020, 26(12), 1117-1129.

It's the active component of vitamin B12 called methylcobalamin, which is believed to help enhance nerve conduction and neuropathic pain. This was to examine whether or not methylcobalamin could improve and/or safely treat peripheral neuropathy, and a systematic review and meta-analysis of randomised controlled trials were performed. These findings suggest that methylcobalamin combination therapy may lead to clinical treatment benefit and increase the rate of nerve conduction in patients with peripheral neuropathy, but the evidence for methylcobalamin monotherapy is unclear.
Evaluation results
15 studies involving 1,707 patients suffering from peripheral neuropathy due to diabetic peripheral neuropathy and herpetic neuropathy were analyzed. Utilizing Cochrane's criteria for assessing risk of bias, it was determined that a majority of the studies (11 out of 15, or 73%) were categorized as having a high risk of bias, while 20% showed some concerns, and 7% were rated as having a low risk of bias. In terms of achieving clinical therapeutic efficacy, mecobalamin administered alone (risk ratio [RR] = 1.17; 95% confidence interval [CI] 1.03-1.33) and in combination with other treatments (RR = 1.32; 95% CI 1.21-1.45) demonstrated greater effectiveness compared to the active control. Regarding nerve conduction velocity (NCV) outcomes, only the mecobalamin combination treatment was found to be beneficial. However, neither mecobalamin alone nor in combination had any significant impact on pain scores or neuropathic symptoms. Throughout the treatment periods, no serious adverse events related to mecobalamin were reported.

Zhang M, et al. Neural plasticity, 2013, 2013(1), 424651.

Methylcobalamin (MeCbl) is the dietary version of vitamin B12. Several studies have demonstrated in experimental and clinical settings that MeCbl can be analgesic. For instance, generalized low back pain, neck pain, diabetic neuropathic pain, subacute herpetic neuralgia, glossopharyngeal neuralgia, trigeminal neuralgia etc.
· Examples of analgesic effects of MeCbl
Hanai et al. showed that oral administration of MeCbl for 4 weeks relieved spontaneous neck pain, allodynia, and paresthesia.
The study of Xu et al. showed that local subcutaneous injection of MeCbl for 4 weeks relieved systemic pain, continuous spontaneous pain, paroxysmal pain, and allodynia.
Singh et al. studied the analgesic effect of MeCbl in combination with other drugs on neuralgia. Oral administration of gabapentin, tramadol, and MeCbl (0.5 mg) reduced pain intensity and reduced the interference of pain on quality of life.
· Possible analgesic mechanisms of MeCbl
MeCbl enhanced the velocity of nerve conduction; it facilitated the regeneration of injured nerves, leading to the restoration of neuromuscular functions in cases of peripheral hyperalgesia and allodynia; and it also suppressed ectopic spontaneous discharges from primary sensory neurons in conditions characterized by neuropathic pain.