What is a potential complication of long-term INH use?

Long-term use of isoniazid (INH) is associated with peripheral neuropathy as a potential complication primarily due to its effects on vitamin B6 (pyridoxine) metabolism. INH can inhibit the enzyme that converts pyridoxine to its active form, which is critical for various neuronal functions. This inhibition can lead to a deficiency of vitamin B6, which is essential for the synthesis of neurotransmitters and maintaining nerve function.

As peripheral nerves become compromised due to this deficiency, patients may experience symptoms such as numbness, tingling, or pain, particularly in the hands and feet. This condition highlights the importance of monitoring individuals on long-term INH therapy and considering vitamin B6 supplementation to mitigate the risk of developing peripheral neuropathy.

While hearing loss and vision impairment can occur in other contexts or due to certain medications, they are not commonly associated with INH. Late-onset diabetes is also not a well-established complication of INH use compared to the clearly documented risk of peripheral neuropathy.