Reviewed on 5/22/2023

Brand Name: Myambutol

Generic Name: Ethambutol

Drug Class: Antitubercular Agents

What Is Ethambutol and How Does It Work?

Ethambutol is a prescription medication used to treat Tuberculosis

  • Ethambutol is available under the following different brand names: Myambutol.

What Are Dosages of Ethambutol?

Adult and pediatric dosage


  • 100mg
  • 400mg


Adult dosage

Prescribing information

  • Initial TB treatment: 15 mg/kg orally once daily
  • Prior TB treatment: 25 mg/kg orally once daily; after 60 days, decrease to 15 mg/kg orally once daily

Daily administration

  • 40-55 kg: 800 mg orally
  • 56-75 kg: 1.2 g orally
  • Over 75 kg: 1.6 g orally

Twice weekly administration

  • 40-55 kg: 2 g orally
  • 56-75 kg: 2.8 g orally
  • Over 75 kg: 4 g orally

3 times per week administration

  • 40-55 kg: 1.2 g orally
  • 56-75 kg: 2 g orally
  • Over 75 kg: 2.4 g orally

Pediatric dosage

Prescribing information: 

  • Children younger than 13 years of age: Not recommended

Guidelines from the American Thoracic Society (ATS), Centers for Disease Control and Prevention (CDC), and the Infectious Diseases Society of America (IDSA)

  • 15-20 mg/kg/day orally; not to exceed 1 g/day or
  • 50 mg/kg orally twice per week; not to exceed 2.5 g/dose

Guidelines from the American Academy of Pediatrics (AAP)

  • 15-25 mg/kg/day orally; not to exceed 1 g/day or 
  • 50 mg/kg orally twice per week; not to exceed 2.5 g/dose

Dosage Considerations – Should be Given as Follows: 

  • See “Dosages”.

What Are Side Effects Associated with Using Ethambutol?

Common side effects of Ethambutol include:

  • itching, 
  • rash, 
  • joint pain, 
  • headache, 
  • dizziness, 
  • nausea, 
  • vomiting, 
  • stomach pain, 
  • indigestion, and
  • loss of appetite 

Serious side effects of Ethambutol include:

  • hives, 
  • difficult breathing, 
  • swelling of the face, lips, tongue, or throat, 
  • vision loss (may be permanent), 
  • blurred vision, 
  • trouble focusing, 
  • loss of vision in one eye that lasts an hour or longer, 
  • increased sensitivity of the eyes to light, 
  • loss of color vision, 
  • pain with eye movement, 
  • pain behind the eyes, 
  • new or worsening cough with fever, 
  • numbness or tingling in your hands or feet, 
  • confusion, 
  • hallucinations,
  • fever, 
  • swollen glands, 
  • painful mouth sores, 
  • skin sores, 
  • cold or flu symptoms, 
  • general ill feeling, 
  • easy bruising, 
  • unusual bleeding (nosebleeds, bleeding gums), 
  • chest pain, 
  • shortness of breath with mild exertion, 
  • little or no urination, 
  • upper stomach pain, 
  • dark urine, 
  • clay-colored stools,
  • yellowing of the skin or eyes (jaundice), 
  • sore throat
  • burning in the eyes, and
  • skin pain followed by a red or purple skin rash that spreads (especially in the face or upper body) and causes blistering and peeling

Rare side effects of Ethambutol include:

  • none 
This is not a complete list of side effects and other serious side effects or health problems may occur as a result of the use of this drug. Call your doctor for medical advice about serious side effects or adverse reactions. You may report side effects or health problems to FDA at 1-800-FDA-1088.

What Other Drugs Interact with Ethambutol?

If your medical doctor is using this medicine to treat your pain, your doctor or pharmacist may already be aware of any possible drug interactions and may be monitoring you for them.  Do not start, stop, or change the dosage of any medicine before checking with your doctor, health care provider, or pharmacist first

This information does not contain all possible interactions or adverse effects. Visit the RxList Drug Interaction Checker for any drug interactions. Therefore, before using this drug, tell your doctor or pharmacist of all the drugs you use. Keep a list of all your medications with you, and share the list with your doctor and pharmacist. Check with your physician if you have health questions or concerns.

What are Warnings and Precautions for Ethambutol?


  • Hypersensitivity
  • Known optic neuritis (unless clinical judgment determines that it may be used)
  • Patients unable to appreciate and report visual side effects or changes in vision (e.g., young children, unconscious patients)

Effects of drug abuse

  • None

Short-Term Effects

  • See “What Are Side Effects Associated with Using Ethambutol?”

Long-Term Effects

  • See “What Are Side Effects Associated with Using Ethambutol?”


  • May produce decreases in visual acuity which appear to be due to optic neuritis; the effect may be related to dose and duration of treatment; the effect is generally reversible when the administration of the drug is discontinued promptly; however, irreversible blindness has been reported
  • Liver toxicities including fatalities reported; baseline and periodic assessment of hepatic function should be performed
  • Not recommended for use in pediatric patients younger than 13 years; safe conditions for use not established
  • Patients with decreased renal function need dosage reduced as determined by serum levels of the drug; the main path of excretion of this drug is by the kidneys
  • The drug may have adverse effects on vision; physical examination should include ophthalmoscopy, finger perimetry, and testing of color discrimination
  • In patients with visual defects such as cataracts, recurrent inflammatory conditions of the eye, optic neuritis, and diabetic retinopathy, the evaluation of changes in visual acuity is more difficult, and care should be taken to be sure the variations in vision are not due to underlying disease conditions
  • In such patients, consideration should be given to the relationship between benefits expected and possible visual deterioration since the evaluation of visual changes is difficult
  • As with any potent drug, baseline and periodic assessment of organ system functions, including renal, hepatic, and hematopoietic, should be performed

Pregnancy and Lactation

  • May be acceptable during pregnancy. 
  • Lactation: enters breast milk; use with caution (AAP Committee states “compatible with nursing”)
Medscape. Ethambutol.

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