Vitamin B-6 is needed for maintaining healthy nerves and muscle cells, and aids in the production of DNA and RNA. Too much synthetic pyridoxine, however, can irritate nerves and create symptoms. The most commonly irritated nerves from pyridoxine toxicity are the smaller peripheral nerves of the hands and feet, which produce numbness in a stocking-glove distribution, according to the Merck Manual website. Although numbness is common, the nerve irritation does not usually affect the senses of touch, temperature or pain. Motor coordination and walking ability often remain intact, although muscle spasms or cramps may be experienced. Discontinuing pyridoxine supplementation (centrum) usually reverses these symptoms within a few weeks.