Ethionamide Disease Interactions

The use of ethionamide is contraindicated in patients with severe liver damage. Like many other antituberculous agents, ethionamide is hepatotoxic. Transient elevations in bilirubin and serum SGOT (AST) and SGPT (ALT) have been reported in 5% of the patients treated with ethionamide. Hepatitis, with or without jaundice, has also been observed, particularly in patients with diabetes mellitus. Therapy with ethionamide should be administered cautiously in patients with liver disease, a history of alcoholism, or diabetes. Liver function tests should be measured at baseline and monthly during therapy, and ethionamide withdrawn at the first signs or symptoms suggestive of liver damage.

Ethionamide is primarily metabolized by the liver. Patients with liver disease may be at greater risk for adverse effects from ethionamide due to decreased drug clearance. Dosage reductions are recommended in these patients.

Peripheral neuropathy has been associated with the use of ethionamide, but much less frequently than with isoniazid, a structurally related agent. Therapy with ethionamide should be administered cautiously in patients with preexisting peripheral neuropathy or risk factors for developing the condition, such as malnutrition, diabetes, and alcoholism. Pyridoxine (vitamin B6) at a dosage of 25 to 50 mg/day has been recommended to prevent or attenuate isoniazid-related peripheral neuropathy and may be considered for patients receiving ethionamide.

The use of ethionamide has occasionally been associated with poor diabetic control. Patients with diabetes mellitus should be monitored more closely during therapy with ethionamide, and their antidiabetic regimen adjusted accordingly.