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Trecator-SC Side Effects

Generic name: ethionamide

Medically reviewed by Last updated on Dec 15, 2022.

Note: This document contains side effect information about ethionamide. Some dosage forms listed on this page may not apply to the brand name Trecator-SC.

Applies to ethionamide: oral tablet.

Serious side effects of Trecator-SC

Along with its needed effects, ethionamide (the active ingredient contained in Trecator-SC) may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.

Check with your doctor immediately if any of the following side effects occur while taking ethionamide:

Less common

  • Clumsiness or unsteadiness
  • confusion
  • mental depression
  • numbness, tingling, burning, or pain in the hands and feet
  • yellow eyes or skin


  • Blindness or vision changes
  • blue-yellow color blindness
  • blurred vision or loss of vision, with or without eye pain
  • burning, crawling, itching, numbness, painful, prickling, "pins and needles", or tingling feelings
  • changes in menstrual periods
  • coldness
  • decreased sexual ability (in males)
  • decreased vision
  • difficulty in concentrating
  • dry, puffy skin
  • fast heartbeat
  • fever
  • hives, itching, or rash
  • hoarseness
  • increased hunger
  • increased sensitivity of the skin to sunlight
  • irritation
  • joint pain, stiffness, or swelling
  • redness or other discoloration of the skin
  • severe sunburn
  • shakiness
  • swelling of the eyelids, face, lips, hands, or feet
  • swelling of the front part of the neck
  • tightness in the chest
  • troubled breathing or swallowing
  • weakness in the hands or feet
  • weight gain

Incidence not known

Other side effects of Trecator-SC

Some side effects of ethionamide may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. Also, your health care professional may be able to tell you about ways to prevent or reduce some of these side effects.

Check with your health care professional if any of the following side effects continue or are bothersome or if you have any questions about them:

More common

  • Abdominal or stomach pain
  • diarrhea
  • increased watering of the mouth
  • loss of appetite
  • metallic taste
  • swelling or inflammation of the mouth
  • weight loss

Incidence not known

  • Blemishes on the skin
  • decreased interest in sexual intercourse
  • enlargement of the breasts (in males)
  • inability to have or keep an erection
  • loss in sexual ability, desire, drive, or performance
  • pimples

For Healthcare Professionals

Applies to ethionamide: oral tablet.


The most commonly reported side effects included abdominal pain, diarrhea, nausea, and vomiting.[Ref]


Approximately 50% of patients are unable to tolerate 1 gram (as a single dose).[Ref]

Very common (10% or more): Adverse gastrointestinal effects (up to 50%)

Common (1% to 10%): Abdominal pain, diarrhea, excessive salivation, gastrointestinal disturbances, nausea, stomatitis, vomiting[Ref]


Common (1% to 10%): Anorexia, weight loss

Rare (0.01% to 0.1%): Pellagra-like syndrome

Frequency not reported: Hypoglycemia[Ref]

Nervous system

Common (1% to 10%): Metallic taste

Rare (0.01% to 0.1%): Neurotoxic effects, peripheral neuritis

Frequency not reported: Dizziness, drowsiness, headache[Ref]


Rare (0.01% to 0.1%): Blurred vision, diplopia, optic neuritis[Ref]


Rare (0.01% to 0.1%): Photosensitivity, rash

Frequency not reported: Acne[Ref]


Rare (0.01% to 0.1%): Purpura, thrombocytopenia[Ref]


Rare (0.01% to 0.1%): Hypersensitivity reactions[Ref]


Frequency not reported: Hepatitis with/without jaundice, transient ALT increases, transient AST increases, transient serum bilirubin increases[Ref]


Frequency not reported: Mental depression, psychotic disturbances, restlessness[Ref]


Frequency not reported: Gynecomastia, hypothyroidism[Ref]


Frequency not reported: Postural hypotension[Ref]


Frequency not reported: Impotence[Ref]

More about Trecator-SC (ethionamide)

Patient resources

Professional resources

Other formulations

Related treatment guides


1. "Product Information. Trecator-SC (ethionamide)." Wyeth-Ayerst Laboratories (2001):

Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

Some side effects may not be reported. You may report them to the FDA.