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Ethambutol Dosage

This dosage information may not include all the information needed to use Ethambutol safely and effectively. See additional information for Ethambutol.

The information at Drugs.com is not a substitute for medical advice. ALWAYS consult your doctor or pharmacist.

Usual Adult Dose for Tuberculosis - Active

Initial treatment: 15 mg/kg orally once a day for 6 to 8 weeks with concurrent isoniazid therapy.
Retreatment: 25 mg/kg orally once a day for 60 days concurrently with at least one other anti-TB drug. After 60 days, decrease dose to 15 mg/kg orally once a day.
As an alternative to single daily dose, a dose of 40 mg/kg orally twice a week or 30 mg/kg orally 3 times a week can be administered. This generally follows 2 weeks of daily therapy. This regimen allows directly observed therapy (DOT).

Usual Adult Dose for Mycobacterium avium-intracellulare - Treatment

900 mg orally once a day. Pulmonary AVI treatment consists of clarithromycin and 2 to 4 other drugs such as ethambutol, rifampin, clofazimine, and/or other agents. The duration of treatment is 18 to 24 months.
Disseminated MAI treatment consists of clarithromycin or azithromycin and 1 to 3 other drugs such as ethambutol, clofazamine, ciprofloxacin, ofloxacin, rifampin, rifabutin, or amikacin. As long as clinical and microbiological response is documented, therapy should be continued for life.

Usual Adult Dose for Mycobacterium avium-intracellulare - Prophylaxis

15 mg/kg orally once a day. Used in combination therapy with clarithromycin or azithromycin. Therapy should be continued for life.

Usual Pediatric Dose for Tuberculosis - Active

Greater than 13 years:
Initial treatment: 15 mg/kg orally once a day for 6 to 8 weeks with concurrent isoniazid therapy.
Retreatment: 25 mg/kg orally once a day for 60 days concurrently with at least one other anti-TB drug. After 60 days, decrease dose to 15 mg/kg orally once a day.
As an alternative to single daily dose, a dose of 40 mg/kg orally twice a week or 30 mg/kg orally 3 times a week can be administered. This generally follows 2 weeks of daily therapy. This regimen allows directly observed therapy (DOT).

Usual Pediatric Dose for Mycobacterium avium-intracellulare - Treatment

Greater than 13 years:
900 mg orally once a day. Pulmonary AVI treatment consists of clarithromycin and 2 to 4 other drugs such as ethambutol, rifampin, clofazimine, and/or other agents. The duration of treatment is 18 to 24 months.
Disseminated MAI treatment consists of clarithromycin or azithromycin and 1 to 3 other drugs such as ethambutol, clofazamine, ciprofloxacin, ofloxacin, rifampin, rifabutin, or amikacin. As long as clinical and microbiological response is documented, therapy should be continued for life.

Usual Pediatric Dose for Mycobacterium avium-intracellulare - Prophylaxis

Greater than 13 years:
15 mg/kg orally once a day. Used in combination therapy with clarithromycin or azithromycin. Therapy should be continued for life.

Renal Dose Adjustments

CrCl less than 10 mL/min: The usual dose may be administered every 48 hours.

CrCl 10 to 50 mL/min: The usual dose may be administered every 24 to 36 hours.

Liver Dose Adjustments

Data not available

Dose Adjustments

Patients with decreased renal function need the dosage reduced as determined by serum levels, since the main path of excretion of this drug is by the kidneys.

Precautions

Ethambutol is contraindicated in patients with known optic neuritis unless clinical judgment determines that it may be administered. Ethambutol is contraindicated in patients who are unable to appreciate and report visual side effects or changes in vision (e.g., young children, unconscious patients).

Due to the risk of optic neuritis associated with ethambutol, caution should be used when treating patients with preexisting neuritis or other vision defects. Ethambutol may produce decreases in visual acuity that appear to be due to optic neuritis. This effect may be related to dosage and duration of treatment. This effect is generally reversible when use of the drug is discontinued promptly. However, irreversible blindness has been observed. Since this 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 make sure that variations in vision are not due to the underlying disease conditions. In these patients, consideration should be given to relationship between benefits expected and possible visual deterioration since evaluation of visual changes is difficult. All patients receiving ethambutol should be instructed to report any vision changes or disturbances. Testing of visual acuity should be performed before beginning ethambutol and periodically during drug administration. Monthly visual acuity testing should be done for patients receiving more than 15 mg per kilogram per day.

Liver toxicities including fatalities have been observed. Baseline and periodic assessment of hepatic function should be performed.

Patients with decreased renal function should have the dosage reduced as determined by serum levels of ethambutol, since the main path of excretion of this drug is by the kidneys. Baseline and periodic assessment of renal function should be performed.

Baseline and periodic assessment of hematopoietic function should be performed.

Ethambutol may elevate serum uric acid levels and should be used cautiously in patients with preexisting gout. Patients should be monitored for hyperuricemia.

There are limited data on the use of ethambutol in elderly patients. One study of 101 patients, 65 years and older, on multiple drug antituberculosis regimens included 94 patients on ethambutol therapy. No differences in safety or tolerability were reported in these patients compared with that reported in adults in general. Other observed clinical experience has not identified differences in responses between the elderly and younger patients, but greater sensitivity of some older individuals cannot be ruled out.

Dialysis

Ethambutol is slightly dialyzable (5% to 20%). The dose should be administered post-dialysis.

Other Comments

Ethambutol or streptomycin are used as part of a combination therapy with isoniazid, rifampin, and pyrazinamide. If susceptibility to isoniazid and rifampin is shown, ethambutol may be discontinued.

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