By Alan R. Gaby, MD
Healthnotes Newswire — A form of vitamin B12 known as methylcobalamin may be capable of preventing one of the serious side effects of a commonly used group of antibiotics, according to a recent study using experimental animals conducted in Shanghai, People's Republic of China.1 In this study, the damaging effect of gentamicin on the inner ear of guinea pigs was markedly reduced by simultaneous administration of methylcobalamin.
Gentamicin is one of a class of antibiotics known as aminoglycosides; other drugs in the class include tobramycin and streptomycin. These drugs, which are usually given by injection in the hospital, are effective against certain serious or difficult-to-treat infections, including tuberculosis, bacterial endocarditis, and some forms of pneumonia. However, all aminoglycosides have the potential to cause damage to the inner ear, or ototoxicity, resulting in often-permanent impairment of hearing or balance, or both. According to one study, the incidence of hearing loss among patients receiving aminoglycosides was 22%;2 and for patients who require streptomycin therapy for more than 60 days, the incidence of ototoxicity may be as high as 75%. Despite these and other side effects (such as kidney damage), aminoglycosides remain the most effective antibiotics against certain bacteria, and doctors consider these drugs essential in many cases.
It is not known how methylcobalamin inhibits the ototoxic effect of gentamicin. However, this form of vitamin B12 has been used successfully to treat a number of conditions associated with damaged nerve cells, including Bell's palsy and the neuropathy that occurs in individuals with diabetes or kidney failure.3 4 Perhaps methylcobalamin also protects the sensitive nerve cells in the inner ear against the noxious effects of aminoglycosides.
Additional research is needed to determine whether vitamin B12 can prevent aminoglycoside-induced ototoxicity in humans. However, considering that vitamin B12 is very safe, and there is no evidence that it interferes with the infection-fighting properties of aminoglycosides, an argument could be made that methylcobalamin therapy should be considered for all patients receiving aminoglycosides. At the very least, this report from China should stimulate clinical trials in humans.
References1. Jin X, Jin X, Sheng X. Methylcobalamin as antagonist to transient ototoxic action of gentamicin. Acta Otolaryngol 2001;121:351–4.
2. Moore RD, Smith CR, Lietman PS. Risk factors for the development of auditory toxicity in patients receiving aminoglycosides. J Infect Dis 1984;149:23–30.
3. Jalaludin MA. Methylcobalamin treatment of Bell's palsy. Methods Find Exp Clin Pharmacol 1995;17:539–44.
4. Kuwabara S, Nakazawa R, Azuma N, et al. Intravenous methylcobalamin treatment for uremic and diabetic neuropathy in chronic hemodialysis patients. Intern Med 1999;38:472–5. Alan R. Gaby, MD, is in practice at the an expert in nutritional therapies, served as a member of the Ad-Hoc Advisory Panel of the National Institutes of Health Office of Alternative Medicine. He is the Medical Editor for Clinical Essentials Alert, is the author of Preventing and Reversing Osteoporosis (Prima, 1994), and co-author of The Natural Pharmacy, 2nd Edition (Healthnotes, Prima, 1999), the A–Z Guide to Drug-Herb-Vitamin Interactions (Healthnotes, Prima, 1999), Clinical Essentials Volume 1 and 2 (Healthnotes, 2000), and The Patient’s Book of Natural Healing (Prima, 1999). Currently he is the Endowed Professor of Nutrition at Bastyr University of Natural Health Sciences, Kenmore, Washington.