Vitamin B6

Vitamin B6 is a group of water-soluble vitamins, part of the vitamin B complex, and that are derivatives of pyridine, the main vitamers are known as pyridoxine, pyridoxal and pyridoxamine. All three form part of the coenzyme pyridoxal 5'-phosphate (PLP) which is involved in many cellular reactions including the synthesis of several amino acids and the metabolism of glucose and lipids.

The antitubercular drug isoniazid is an inactive derivative of pyridoxal phosphate, hence vitamin B6 needs to be co-administered in patients on isoniazid.

Related pathology

• vitamin B6 deficiency (hypovitaminosis B6) is rare, seen in alcoholics, women on the oral contraceptive pill (OCP) and neonates fed on B6-deficient formula
• vitamin B6 excess (hypervitaminosis B6) may produce neurological symptoms