Vitamin B6 (pyridoxine) for hand-foot syndrome and other uses

Hand-foot syndrome is a common side effect of capecitabine, fluorouracil infusions and pegylated liposomal doxorubicin, and pyridoxine has been used for it empirically. Memorial Sloan Kettering's About Herbs entry reports that several randomised trials did not find benefit, although higher doses may help and one study found fewer capecitabine dose modifications and less severe hand-foot syndrome without any effect on how well chemotherapy worked. Dietary B6 is associated with lower risk of colorectal and some other cancers, but MSK notes that supplements do not show the same association: in the Women's Health Study, B6 with B12 and folate did not reduce breast or invasive cancer risk, and long-term supplementation was associated with more lung cancer, especially in male smokers. High intakes cause sensory and motor neuropathy and ataxia; MSK describes three elderly patients taking 600 mg a day for years whose neuropathy had not improved two years after stopping. B6 also reduced the effect of the chemotherapy drug altretamine in one study and speeds the breakdown of levodopa. Urea-based creams, dose adjustment and, for capecitabine, the guidance of the treating team remain the main management.