ETHIONAMIDE is an antibiotic. It is used to treat tuberculosis (TB). This medicine is used with other medicines and should never be used alone. It will not work for colds, flu, or other viral infections. Compare antimycobacterials.

What is Trecator?

Commonly Used Brand Name(s)Trecator, Trecator-SC

Therapeutic ClassificationsAntitubercular




Ethionamide is used together with other medicines to treat tuberculosis (TB). Ethionamide belongs to the class of medicines called antibiotics and works to kill or prevent the growth of bacteria. However, it will not work for colds, flu, or other virus infections.

This medicine is available only with your doctor's prescription.

Once a medicine has been approved for marketing for a certain use, experience may show that it is also useful for other medical problems. Although these uses are not included in product labeling, ethionamide is used in certain patients with the following medical conditions:

  • Atypical mycobacterial infections, such as Mycobacterium avium complex (MAC).
  • Leprosy (Hansen's disease).

Proper UseTOP

Take this medicine exactly as directed by your doctor. Do not take more of it, do not take it more often, and do not take it for a longer time than your doctor ordered. To do so may increase the chance for side effects.

Ethionamide may be taken with meals or after meals, if it upsets your stomach.

To help clear up your tuberculosis (TB) completely, it is very important that you keep taking this medicine for the full time of treatment, even if you begin to feel better after a few weeks. You may have to take it every day for 1 to 2 years or more. It is important that you do not miss any doses.

Your doctor may also want you to take pyridoxine (eg, Hexa-Betalin, vitamin B6) every day to help prevent or lessen some of the side effects of ethionamide. If so, it is very important to take pyridoxine every day along with this medicine. Do not miss any doses.


The dose of this medicine will be different for different patients. Follow your doctor's orders or the directions on the label. The following information includes only the average doses of this medicine. If your dose is different, do not change it unless your doctor tells you to do so.

The amount of medicine that you take depends on the strength of the medicine. Also, the number of doses you take each day, the time allowed between doses, and the length of time you take the medicine depend on the medical problem for which you are using the medicine.

  • For oral dosage form (tablets):
    • For the treatment of tuberculosis (TB):
      • Adults—Dose is based on body weight and must determined by your doctor. The starting dose is usually 250 milligrams (mg) once a day. Your doctor may increase your dose as needed. However, the dose is usually not more than 1000 mg per day.
      • Children 12 years of age and older—Dose is based on body weight and must be determined by your doctor. The dose is usually 10 to 20 milligrams (mg) per kilogram (kg) of body weight per day, divided in 2 or 3 doses taken after meals OR 15 mg per kg of body weight per day, taken as a single dose.
      • Children younger than 12 years of age—Use is not recommended.

Missed DoseTOP

If you miss a dose of this medicine, take it as soon as possible. However, if it is almost time for your next dose, skip the missed dose and go back to your regular dosing schedule. Do not double doses.

Use & StorageTOP

Store the medicine in a closed container at room temperature, away from heat, moisture, and direct light. Keep from freezing.

Keep out of the reach of children.

Do not keep outdated medicine or medicine no longer needed.

Ask your healthcare professional how you should dispose of any medicine you do not use.

Before UsingTOP

In deciding to use a medicine, the risks of taking the medicine must be weighed against the good it will do. This is a decision you and your doctor will make. For this medicine, the following should be considered:


Tell your doctor if you have ever had any unusual or allergic reaction to this medicine or any other medicines. Also tell your health care professional if you have any other types of allergies, such as to foods, dyes, preservatives, or animals. For non-prescription products, read the label or package ingredients carefully.


Use of ethionamide is not recommended in children younger than 12 years of age.


No information is available on the relationship of age to the effects of ethionamide in geriatric patients. However, elderly patients are more likely to have age-related kidney, liver, or heart problems, which may require caution in patients receiving ethionamide.


Pregnancy CategoryExplanation
All TrimestersCAnimal studies have shown an adverse effect and there are no adequate studies in pregnant women OR no animal studies have been conducted and there are no adequate studies in pregnant women.

Breast FeedingTOP

There are no adequate studies in women for determining infant risk when using this medication during breastfeeding. Weigh the potential benefits against the potential risks before taking this medication while breastfeeding.

Drug InteractionsTOP

Although certain medicines should not be used together at all, in other cases two different medicines may be used together even if an interaction might occur. In these cases, your doctor may want to change the dose, or other precautions may be necessary. When you are taking this medicine, it is especially important that your healthcare professional know if you are taking any of the medicines listed below. The following interactions have been selected on the basis of their potential significance and are not necessarily all-inclusive.

Using this medicine with any of the following medicines is usually not recommended, but may be required in some cases. If both medicines are prescribed together, your doctor may change the dose or how often you use one or both of the medicines.

Other InteractionsTOP

Certain medicines should not be used at or around the time of eating food or eating certain types of food since interactions may occur. Using alcohol or tobacco with certain medicines may also cause interactions to occur. Discuss with your healthcare professional the use of your medicine with food, alcohol, or tobacco.

Other Medical ProblemsTOP

The presence of other medical problems may affect the use of this medicine. Make sure you tell your doctor if you have any other medical problems, especially:

  • Diabetes or
  • Thyroid problems—Use with caution. May make these conditions worse.
  • Liver disease, severe—Should not be used in patients with this condition.


It is very important that your doctor check your progress at regular visits. This will allow your doctor to see if the medicine is working properly and to decide if you should continue to take it. Blood tests will be needed to check for unwanted effects.

If your symptoms do not improve within 2 to 3 weeks, or if they become worse, check with your doctor.

Since this medicine may cause blurred vision or loss of vision, with or without eye pain, make sure you know how you react to this medicine before you drive, use machines, or do anything else that could be dangerous if you are not able to see well.

Avoid taking alcohol while using this medicine.

Do not take other medicines unless they have been discussed with your doctor. This includes prescription or nonprescription (over-the-counter [OTC]) medicines and herbal or vitamin supplements.

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