Efficacy and Safety of Mecobalamin on Peripheral Neuropathy: A Systematic Review and Meta-analysis of Randomized Controlled Trials.
Sawangjit Ratree,Thongphui Suntana,Chaichompu Wanida,Phumart Panumart
Journal of alternative and complementary medicine (New York, N.Y.)
To assess the efficacy and safety of mecobalamin on peripheral neuropathy. Mecobalamin is an active form of vitamin B12 that has been suggested to be beneficial in improving nerve conduction and neuropathic pain symptoms. Although it is already widely used in Asia for the treatment of peripheral neuropathies, its efficacy remains unclear. Relevant electronic databases were systematically searched for randomized controlled trials investigating the efficacy and safety of mecobalamin on peripheral neuropathy, from inception through December 2019. Study selection, data extraction, and quality assessment were performed independently by two reviewers. The clinical therapeutic efficacy, pain score, neuropathic symptom score, nerve conduction velocities (NCVs), and adverse events of mecobalamin were assessed and were pooled by using a random-effects model. Heterogeneity was assessed by and chi-squared tests. Fifteen studies with 1707 peripheral neuropathy patients caused by diabetic peripheral neuropathy and herpetic neuropathy were included. Based on Cochrane's risk of bias criteria, most of the included studies (11/15, 73%) were rated high risk of bias, whereas 20% and 7% were rated some concerns and low risk of bias, respectively. In terms of the proportion of patients achieving clinical therapeutic efficacy, mecobalamin alone (risk ratio [RR] = 1.17; 95% confidence interval [CI] 1.03-1.33) and mecobalamin in combination (RR = 1.32; 95% CI 1.21-1.45) are more effective than active control. For NCV outcomes, only mecobalamin combination treatment was effective. Neither mecobalamin alone nor mecobalamin in combination is effective on the pain score and neuropathic symptom outcomes. No serious adverse events associated with mecobalamin were reported during the treatment periods. Our findings indicate that mecobalamin in combination may be effective in improving clinical therapeutic efficacy and NCV outcomes for peripheral neuropathy patients, but the evidence is not clear for mecobalamin alone. More high-quality studies are required to confirm this finding.
[A case of subacute combined degeneration with normal serum vitamin B12 level].
Nagaishi Akiko,Takashima Hiroshi,Fukuda Yasuo,Kuroda Yasuo
Rinsho shinkeigaku = Clinical neurology
A 40-year-old woman was admitted to our hospital because of pancytopenia with megaloblastic anemia. Two months later she complained of rapidly progressive gait disturbance and numbness in the distal part of limbs. She also told that her hair had turned totally gray in the third decade. Neurologically, mental state, cranial nerves and cerebellar functions were normal. Superficial sensations were impaired below the lower thoracic level and deep sensations were completely lost in the lower limbs. Moderate weakness was found in the lower limbs, symmetrically. Deep tendon reflexes were diminished in the upper limbs and absent in the lower limbs. Babinski's reflex was positive bilaterally. MR images of the spinal cord showed hyperintensity in the posterior column below the thoracic cord. Although the serum level of vitamin B12 was within normal range, serum homocysteine level was elevated markedly. Under the diagnosis of subacute combined degeneration (SCD) due to possible vitamin B12 deficiency, the treatment with intravenous injections of 500 micrograms/day of mecobalamin was undertaken. Muscle strength and sensory impairment improved progressively and she became able to walk with a cane. The coloration of her gray hair was also noted. After treatment, pancytopenia and megaloblastic anemia also markedly improved. Vitamin B12 became high in serum concentration and the serum level of homocysteine became normal. These clinical and laboratory findings support the diagnosis of SCD with normal serum level of vitamin B12 in our case, suggesting that the level of vitamin B12 in serum does not always correlate with that in tissue and, therefore, SCD should not be excluded just only by the reason of normal serum vitamin B12 level.
Differential efficacy of methylcobalamin and alpha-lipoic acid treatment on symptoms of diabetic peripheral neuropathy.
Han Yajuan,Wang Min,Shen Jie,Zhang Zhen,Zhao Min,Huang Jing,Chen Youming,Chen Zhi,Hu Yulan,Wang Yubing
BACKGROUND:Diabetic hyperglycemia damages peripheral nerves by triggering ischemia, oxidative stress, and inflammation. Alpha-lipoic acid (ALA) and methylcobalamin (MC) are known to improve signs of diabetic peripheral neuropathy (DPN), possibly by enhancing neural and vascular endothelial cell metabolism and antioxidant capacity. We evaluated differences in efficacy following short-term MC or ALA treatment on DPN symptoms to guide clinical drug selection. METHODS:Forty DPN patients were randomly divided into MC and ALA treatment groups (both N.=20) and assessed by the Toronto Clinical Neuropathy Scoring System (TCSS), total symptom score (TSS), visual analog scale (VAS) of positive symptoms, and easy sensory test (EST) for negative symptoms before and after 2 weeks of treatment. Serum malondialdehyde (MDA) and superoxide dismutase (SOD) were also measured. RESULTS:Neuropathy as measured by TCSS, TSS, and VAS scores was significantly reduced by both treatments (P<0.05) but magnitude varied by symptom. The VAS score reductions for burning and pain were significantly greater following ALA (P<0.01), while MC reduced numbness and paresthesia VAS scores to a slightly greater extent than ALA (P>0.05). Numbers of abnormal (low-response) points for pressure and pinprick sensation were reduced by MC but not by ALA, while both treatments induced a significant reduction in vibratory perception threshold (P<0.01). Neither MC nor ALA improved temperature sensation or tendon reflexes (P>0.05). Alpha-lipoic acid, increased SOD and reduced MDA (P<0.05), indicating enhanced antioxidant capacity, while MC had no effect. CONCLUSIONS:Due to differences in efficacy, MC or ALA should be chosen according to the symptoms of individual patients.
[Effect of mecobalamin on diabetic neuropathies. Beijing Methycobal Clinical Trial Collaborative Group].
Zhonghua nei ke za zhi
OBJECTIVE:To investigate the effect of mecobalamin on diabetic neuropathies. METHODS:One hundred and eight patients with non-insulin dependent diabetes mellitus were involved in a randomized positive-control clinical trial. 62 cases were treated with mecobalamin 500 microg intramuscularly three times a week for four weeks then followed by 500 microg orally three times a day for additional eight weeks. 46 cases were treated with vitamin B(12) in the same way and served as controls. RESULTS:Twelve weeks after the treatment, spontaneous pain and numbness of limbs were improved by 73% and 75% in the mecobalamin group, which were much higher than those in the controls (36% and 45% respectively). Hypoesthesia, hotness, coldness, oral dryness and dysuria showed better response in the mecobalamin group than in the controls (55% vs 25%, 52% vs 18%, 59% vs 30%, 53% vs 19%, 63% vs 20% respectively). Mecobalamin also benefited nerve reflection and conduction velocity to a certain extent. No obvious side effects were found. CONCLUSION:Mecobalamin might be worthy of use as a safe agent in the treatment of diabetic neuropathies.