Ethionamide

Ethionamide is a congener of INH, but cross-resistance does not occur. Ethionamide can inhibit acetylation of isoniazid It is effective after oral administration and is widely distributed including the CSF Adverse effects that limit its use include gastric irritation, hepatotoxicity, peripheral neuropathies, and optic neuritis. Supplementation with vitamin B6 (pyridoxine) may lessen the severity of the neurologic side effects.