The role of methylcobalamin in managing neuropathic pain: Addressing challenges and exploring solutions for improved patient outcomes

Abstract

The escalating global diabetes burden, particularly in India, where 77 million cases exist, is exacerbated by factors such as obesity and unhealthy habits, with an anticipated rise to 134 million by 2045. Diabetic neuropathy affects 29.2% of the Indian population, with majority experiencing vitamin B12 deficiency. Challenges in B12 absorption arise from acid-suppressing medications, metformin use and increased reverse osmosis (RO) water consumption. Methylcobalamin, a bioactive B12 form, shows promise for neuropathy management, with subcutaneous administration preferred for its efficacy and convenience over intramuscular injections. The methodology involved a thorough search of PubMed and Google Scholar using relevant keywords, with articles screened based on specific criteria. In our study, we surveyed physicians, diabetologists, orthopaedics and neurophysicians using a questionnaire. We focused on the usage of vitamin B12 injections in patients with diabetic neuropathic pain and gathered feedback on their efficacy. It focused on comparative studies of SC (Subcutaneous) and IM (Intramuscular) administration of vitamin B12 in diabetes-related neuropathic pain. Methodological quality assessment and data synthesis summarized key findings on bioequivalence, pharmacokinetics, clinical outcomes and practitioner preferences for SC versus IM administration. Intramuscular administration is often avoided due to discomfort and frequent clinic visits. About 50% of practitioners prefer subcutaneous vitamin B12 injections. Metformin therapy may cause vitamin B12 deficiency. Despite some reluctance, a regimen of five vitamin B12 injections alternated every other day is recommended. Compliance with injections is moderate. Two-thirds of practitioners are aware of the subcutaneous route for vitamin B12 administration, but few know about comparative trials. Patient compliance could improve with self-administered pre-filled syringes (PFS). The conventional IM method of administering methylcobalamin may lead to patient non-compliance due to injection site discomfort. However, subcutaneous PFS of methylcobalamin provide a solution to this issue. PFSs offer a practical option for diverse patient groups, including those on long-term metformin therapy, individuals with low adherence to vitamin B12 supplements and recently diagnosed cases of vitamin B12 deficiency. The convenience of at-home PFS administration reduces the necessity for frequent clinic visits.