Vitamin B12 (cyanocobalamin and its derivatives) is indicated in the treatment of pernicious anemia, and preventing and treating vitamin B12 deficiency. Deficiency of vitamin B12 leads to demyelination and other neurological damage. In combination with other B vitamins it has been shown to potentiate the analgesic effect of NSIDs in patients with pain of different origins, including neuropathic pain. When used with vitamins B6 and B9, vitamin B12 has been shown to reduce the risk of age-related macular degeneration. Cyanocobalamin tougher with folic acid reduces blood homocysteine concentrations. It is also used to treat cyanide poisoning.