Oral Methylcobalamin Improves Symptoms of Diabetic Polyneuropathy in 24 Weeks: Study
USA: Oral methylcobalamin at a daily dose of 1,500 μg significantly reduced symptoms of diabetic polyneuropathy over 24 weeks, with improvements evident as early as six weeks after treatment initiation, according to a prospective clinical study. The findings suggest that methylcobalamin may help alleviate neuropathic symptoms and prevent the development of new symptoms in patients with diabetic polyneuropathy.
The study, published in the Journal of Diabetes Mellitus, evaluated the clinical and neurophysiological effects of oral methylcobalamin (vitamin B12) in adults with diabetic polyneuropathy (DPN), a common complication of diabetes that causes chronic pain, sensory disturbances, and impaired quality of life.
Although vitamin B preparations are frequently prescribed for peripheral neuropathy, evidence supporting their effectiveness has remained inconsistent, and they are not routinely recommended in current treatment guidelines. The researchers therefore investigated whether prolonged methylcobalamin therapy could improve symptoms and nerve function in patients with DPN.
The prospective, open-label study enrolled 48 adults with diabetic polyneuropathy. Participants received oral methylcobalamin 500 μg three times daily (1,500 μg/day) for 24 weeks and underwent clinical assessments at 6, 12, 18, and 24 weeks. The primary outcome was improvement in the Toronto Clinical Scoring System (CSS), while secondary outcomes included patient- and clinician-rereported symptom improvement and changes in nerve conduction parameters.
Key findings
- Methylcobalamin treatment produced a significant and progressive reduction in Toronto Clinical Scoring System scores over 24 weeks, indicating improvement in neuropathy severity.
- Clinical improvement became evident as early as six weeks after treatment initiation.
- Benefits were observed regardless of diabetes duration and across patients with mild, moderate, and severe diabetic polyneuropathy.
- Symptoms including tingling, upper limb complaints, and ataxia improved significantly during treatment.
- Neurological signs, including impaired vibration sense, position sense, pinprick sensation, and right knee reflex, also showed significant improvement.
- Patients who did not have these symptoms at baseline generally remained symptom-free throughout the 24-week study.
- The largest reductions in symptom frequency were seen for tingling (48.15%), weakness (42.86%), and pain (36.36%).
- Nerve conduction testing demonstrated significant improvement in ulnar nerve amplitude, conduction velocity, and distal latency.
The treatment was well tolerated, with a 77% completion rate and only one treatment-related withdrawal due to dizziness.
The researchers concluded that oral methylcobalamin (1,500 μg/day) reduced the frequency and severity of common diabetic polyneuropathy symptoms and helped prevent the emergence of new symptoms over 24 weeks. While improvements were also seen in some nerve conduction measures, they emphasized the need for larger controlled studies to confirm its long-term clinical benefits.
Reference:
J Diabetes Mellitus 2012; 2(4): 408-412
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