Clinical efficacy of intravenous plus oral mecobalamin in patients with peripheral neuropathy using vibration perception thresholds as an indicator of improvement

Abstract Mecobalamin has been widely used in the treatment of patients with peripheral neuropathy. Several studies have investigated oral, intravenous (IV), or intramuscular administration of mecobalamin, but no studies on the usefulness of a combination of these routes have been reported. In addition, drug efficacy has been evaluated mainly from subjective symptoms, the severity of which is difficult to express numerically. In the present study, the effectiveness of two practical regimens of mecobalamin was investigated: (1) oral administration of 500 μg of mecobalamin three times a day for at least 8 weeks (O group); and (2) IV administration of 500 μg/d of mecobalamin three times a week for 4 weeks followed by oral administration of 500 μg of mecobalamin three times a day for at least 4 weeks (VO group). Not only were the changes in subjective symptoms and neurologic findings evaluated, but vibration perception thresholds were also monitored to evaluate the efficacy of each regimen as objectively as possible. Overall improvement was evaluated as "improved" or "markedly improved" in 66.6% of the VO group and 39.1% of the O group. Vibration perception thresholds of the lower extremities were significantly improved in patients in the VO group, whereas patients in the O group did not show clear improvement. The regimen was evaluated as "useful" or "highly useful" in 71.4% of the VO group and 43.5% of the O group. The investigators concluded that the VO regimen is highly effective, and it is recommended in patients who require more rapid and greater improvement of neurologic symptoms.