Sections View Full Chapter Figures Tables Videos Annotate Full Chapter Figures Tables Videos Supplementary Content + Download Section PDF Listen ++ For further information, see CMDT Part 29-14: Vitamin B6 Deficiency + Key Features Download Section PDF Listen +++ ++ Vitamin B6 deficiency most commonly occurs as a result of Alcoholism Variety of medications, especially isoniazid, cycloserine, penicillamine, and oral contraceptives Although inborn errors of metabolism and other pyridoxine-responsive syndromes are not clearly due to vitamin B6 deficiency, they commonly respond to high doses of the vitamin + Clinical Findings Download Section PDF Listen +++ ++ Mouth soreness Glossitis Cheilosis Weakness Irritability Severe deficiency can result in peripheral neuropathy, anemia, seizures May be a correlation between low vitamin B6 levels and a variety of clinical conditions, including inflammatory diseases and certain cancers May be seen concomitantly in patients who have common variable immunodeficiency + Diagnosis Download Section PDF Listen +++ ++ Serum pyridoxal phosphate levels Normal levels vary per laboratory They are typically > 5.0 ng/mL + Treatment Download Section PDF Listen +++ ++ Vitamin B6, 10–20 mg orally once daily Patients taking medications that interfere with pyridoxine metabolism (such as isoniazid) may need doses as high as 100 mg/day Patients with inborn errors of metabolism require up to 600 mg/day Prophylaxis with vitamin B6 should be routinely given to Patients receiving medications (such as isoniazid) that interfere with pyridoxine metabolism Older patients Patients with alcoholism Patients of lower socioeconomic status B6 supplementation has no benefits on cardiovascular outcomes