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Ethionamide Side Effects

For the Consumer

Applies to ethionamide: oral tablet

In addition to its needed effects, some unwanted effects may be caused by ethionamide. In the event that any of these side effects do occur, they may require medical attention.

Major Side Effects

You should check with your doctor immediately if any of these side effects occur when taking ethionamide:

Less common:
  • Clumsiness or unsteadiness
  • confusion
  • mental depression
  • mood or other mental changes
  • numbness, tingling, burning, or pain in hands and feet
  • yellow eyes or skin
  • Blurred vision or loss of vision, with or without eye pain
  • changes in menstrual periods
  • coldness
  • decreased sexual ability (in males)
  • difficulty in concentrating
  • dry, puffy skin
  • faster heartbeat
  • increased hunger
  • nervousness
  • shakiness
  • skin rash
  • swelling of front part of neck
  • weight gain

Minor Side Effects

Some of the side effects that can occur with ethionamide may not need medical attention. As your body adjusts to the medicine during treatment these side effects may go away. Your health care professional may also be able to tell you about ways to reduce or prevent some of these side effects. If any of the following side effects continue, are bothersome or if you have any questions about them, check with your health care professional:

More common:
  • Dizziness (especially when getting up from a lying or sitting position)
  • loss of appetite
  • metallic taste
  • nausea or vomiting
  • sore mouth
Less common or rare:
  • Enlargement of the breasts (in males)

For Healthcare Professionals

Applies to ethionamide: oral tablet


Gastrointestinal side effects are the most common side effects of ethionamide and may be dose-related. They have included nausea, vomiting, diarrhea, abdominal pain excessive salivation, metallic taste, stomatitis, anorexia, and weight loss. Approximately one-half of patients cannot tolerate 1 gram as a single dose.[Ref]

Nervous system

Nervous system side effects have included psychotic disturbances, mental depression, drowsiness, dizziness, restlessness, headache, peripheral neuritis, and a pellagra-like syndrome. Concomitant pyridoxine has been recommended to prevent or relieve neurotoxic effects.[Ref]


Ocular side effects have rarely included optic neuritis, diplopia, and blurred vision.[Ref]


Hepatic side effects have included transient increases in serum bilirubin, SGOT, SGPT, and hepatitis with or without jaundice.[Ref]


Hypersensitivity reactions have rarely included rash, photosensitivity, thrombocytopenia, and purpura.[Ref]


Metabolic side effects have included hypoglycemia and hypothyroidism.[Ref]


Genitourinary side effects have included gynecomastia and impotence.[Ref]


Dermatologic side effects have included rash and acne.[Ref]


Hematologic side effects have included thrombocytopenia and purpura.[Ref]


Cardiovascular side effects have included postural hypotension.[Ref]


1. "Product Information. Trecator-SC (ethionamide)." Wyeth-Ayerst Laboratories, Philadelphia, PA.

2. McDonnell ME, Braverman LE, Bernardo J "Hypothyroidism due to ethionamide." N Engl J Med 352 (2005): 2757-9

3. Hussey HH "Editorial: Gynecomastia." JAMA 228 (1974): 1423

Not all side effects for ethionamide may be reported. You should always consult a doctor or healthcare professional for medical advice. Side effects can be reported to the FDA here.

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