What are common adverse effects of ethionamide that may limit its use?

• A. Gastrointestinal upset, hepatotoxicity, hypothyroidism, and skin rashes.
• B. Renal failure and edema.
• C. Optic neuritis.
• D. Hyperglycemia.

Answer: (A)

Common adverse effects that limit ethionamide use include gastrointestinal upset, hepatotoxicity, hypothyroidism, and skin rashes. These effects are characteristic and directly impact how well a patient can tolerate the drug. GI upset can make dosing uncomfortable and reduce adherence. Hepatotoxicity is a serious concern that requires monitoring liver enzymes and may necessitate stopping the drug if results worsen. Hypothyroidism occurs because ethionamide can interfere with thyroid hormone synthesis, so some patients may develop fatigue, weight gain, or cold intolerance and may need thyroid function assessment and management. Skin reactions range from mild rashes to more noticeable hypersensitivity, sometimes prompting dose adjustment or discontinuation.

Renal failure and edema are not typical primary limiting effects of ethionamide, optic neuritis is more associated with ethambutol, and hyperglycemia is not a common hallmark adverse effect of this drug.