How does INH affect vitamin B6 levels in the body?

Isoniazid (INH) is an antibiotic commonly used to treat tuberculosis. One significant metabolic effect of INH is its impact on vitamin B6 levels in the body. INH interferes with the metabolism of vitamin B6 (pyridoxine) by inhibiting the enzyme that converts it into its active form, pyridoxal phosphate. This disruption in metabolism can lead to decreased availability of the active form of vitamin B6, resulting in a deficiency.

Vitamin B6 is essential for numerous bodily functions, including the synthesis of neurotransmitters, the metabolism of amino acids, and the production of hemoglobin. When its levels are not adequate, a variety of symptoms can arise, including peripheral neuropathy, which is commonly associated with INH treatment. This is why supplementation with vitamin B6 is often recommended for patients undergoing treatment with isoniazid to prevent deficiency.

In contrast, increases in vitamin B6 levels, no effect on vitamin B6 levels, or enhancements in vitamin B6 absorption do not accurately reflect the known pharmacological interactions of INH and vitamin B6, which is why these alternatives do not hold true in this context.