Vitamin B₆ Deficiency

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

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

Serum pyridoxal phosphate levels

• Normal levels vary per laboratory

• They are typically > 5.0 ng/mL

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