Which vitamin level should be monitored in patients receiving INH?

Patients receiving isoniazid (INH) should have their vitamin B6 levels monitored. INH can interfere with the metabolism of vitamin B6, leading to a deficiency, which can result in peripheral neuropathy and other neurological symptoms. This happens because INH acts as a pyridoxine antagonist, thereby hindering the conversion of pyridoxine (vitamin B6) into its active form, which is crucial for neurotransmitter synthesis and other essential bodily functions.

Monitoring vitamin B6 is particularly important because the risk of deficiency increases with prolonged use of INH. To mitigate the potential adverse effects associated with low vitamin B6 levels, healthcare providers often recommend supplementation during INH therapy, especially for patients at higher risk for neuropathies.

In contrast, while vitamins like C, B12, and D play important roles in overall health, their levels are not specifically affected by INH in the way that vitamin B6 is. Therefore, the focus on monitoring vitamin B6 directly relates to the unique side effects associated with isoniazid treatment.