In the U.S.—

In Canada—

• Antibacterial, antimycobacterial

Ethambutol (e-THAM-byoo-tole) is used to treat tuberculosis (TB). It is used with other medicines for TB. This medicine may also be used for other problems as determined by your doctor.

To help clear up your tuberculosis (TB) infection completely, you must keep taking this medicine for the full time of treatment, even if you begin to feel better. This is very important. It is also important that you do not miss any doses.

Ethambutol is available only with your doctor's prescription, in the following dosage form:

Oral
• Tablets (U.S. and Canada)

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 ethambutol, the following should be considered:

Allergies—Tell your doctor if you have ever had any unusual or allergic reaction to ethambutol. Also tell your health care professional if you are allergic to any other substances, such as foods, preservatives, or dyes.

Pregnancy—Pregnant women with tuberculosis (TB) should be treated with TB medicines, including ethambutol. Ethambutol has not been shown to cause birth defects or other problems in humans. However, studies in animals have shown that ethambutol causes cleft palate, skull and spine defects, absence of one eye, and hare lip.

Breast-feeding—Ethambutol passes into breast milk. However, ethambutol has not been shown to cause problems in nursing babies.

Children—This medicine has been tested in children 13 years of age or older and has not been shown to cause different side effects or problems than it does in adults. Ethambutol may be used for children with TB when other medicines cannot be used. However, ethambutol is usually not used in children up to 6 years of age because it may be hard to tell if they are having side effects affecting their eyes.

Older adults—Many medicines have not been studied specifically in older people. Therefore, it may not be known whether they work exactly the same way they do in younger adults. Although there is no specific information comparing use of ethambutol in the elderly with its use in other age groups, this medicine is not expected to cause different side effects or problems in older people than it does in younger adults.

Other medicines—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. Tell your health care professional if you are taking any other prescription or nonprescription (over-the-counter [OTC]) medicine.

• Gouty arthritis—Ethambutol may cause or worsen attacks of gout

• Kidney disease—Patients with kidney disease may be more likely to have side effects

• Optic neuritis (eye nerve damage)—Ethambutol may cause or worsen eye disease

Ethambutol may be taken with food if this medicine 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 as long as 1 to 2 years or more. It is important that you do not miss any doses.

Dosing—

The dose of ethambutol 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 ethambutol. If your dose is different, do not change it unless your doctor tells you to do so.

The number of tablets that you take depends on the strength of the medicine.

• For oral dosage form (tablets):
  • For the treatment of tuberculosis (TB):
    • Adults and children 13 years of age and older—15 to 25 milligrams (mg) per kilogram (kg) (6.8 to 11.4 mg per pound) of body weight once a day. Instead, your doctor may tell you to take 50 mg per kg (22.8 mg per pound) of body weight, up to a total of 2.5 grams, two times a week. Another dose that your doctor may tell you to take is 25 to 30 mg per kg (11.4 to 13.6 mg per pound) of body weight, up to a total of 2.5 grams, three times a week. Ethambutol must be taken with other medicines to treat tuberculosis.
    • Infants and children up to 13 years of age—Use and dose must be determined by your doctor.

Missed dose—

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.

Storage—

To store this medicine:

• Keep out of the reach of children.
• Store away from heat and direct light.
• Do not store in the bathroom, near the kitchen sink, or in other damp places. Heat or moisture may cause the medicine to break down.
• Do not keep outdated medicine or medicine no longer needed. Be sure that any discarded medicine is out of the reach of children.

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

It is very important that your doctor check your progress at regular visits.

Check with your doctor immediately if blurred vision, eye pain, red-green color blindness, or loss of vision occurs during treatment . Your doctor may want you to have your eyes checked by an ophthalmologist (eye doctor). Also, 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 alert or able to see well.

Along with its needed effects, a medicine 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:

• Less common
  • Chills;  pain and swelling of joints, especially big toe, ankle, or knee;  tense, hot skin over affected joints 
  
  

• Rare
  • Blurred vision, eye pain, red-green color blindness, or any loss of vision (more common with high doses);  fever;  joint pain;  numbness, tingling, burning pain, or weakness in hands or feet;  skin rash 
  
  

Other side effects may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. However, check with your doctor if any of the following side effects continue or are bothersome:

• Less common
  • Abdominal pain;  confusion;  headache;  loss of appetite;  nausea and vomiting 
  
  

Other side effects not listed above may also occur in some patients. If you notice any other effects, check with your doctor.

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 this use is not included in product labeling, ethambutol is used in certain patients with the following medical condition:

• Atypical mycobacterial infections, such as Mycobacterium avium complex (MAC)

Other than the above information, there is no additional information relating to proper use, precautions, or side effects for this use.