Ethambutol (Antibiotic)

Summary Information
Classification Chemicals / Complex Chemical Agents / Type:

(This chemicals section is currently predominantly used in Wildpro to link different data types and demonstrate inter-relationships. It does not contain detailed information on the chemical itself.)

Alternative Names --
Notes Information in this page has been entered to support the current volumes of Wildpro and further information will be added as new volumes are completed. This page is not intended to substitute for the manufacturer's data sheet and the information is not yet complete for all species, or for all contra-indications etc.

CAUTION: Before any pharmaceutical product is used, the manufacturer's data sheet, containing information on uses, dosage and administration, contra-indications, warnings etc., should always be consulted. It is important to remember that licensing of pharmaceutical products for use in a particular species/condition, as well as mandatory meat and milk withdrawal times for food-producing animals, varies between countries and changes with time. Withdrawal times also may vary between different pharmaceutical formulations and depending on route of administration. In the EU, the prescription cascade must be followed (see LCofC1.2H and W564.Apr05.w1); note that specific restrictions apply for food-producing animals. In the USA, FARAD may be consulted regarding residues and meat and milk withdrawal times.

  • A trial on five elephants (two female Elephas maximus - Asian Elephant, one male Elephas maximus - Asian Elephant and two male Loxodonta africana - African Elephant) being treated for tuberculosis or exposure to Mycobacterium tuberculosis. Orally administered ethambutol at 30 m/kg bodyweight was rapidly absorbed; peak serum concentrations occurred at 1.0 - 2.0 hours after dosing then concentrations declined biexponentially, indicating possible distribution into deep tissues. The mean apparent volume of distribution was 9.0 L/kg and the estimated terminal half-life was 3.84 h. The AUC was large and exposure levels were considered good. Based on this data and the typical minimum inhibitory concentration for ethambutol against Mycobacterium tuberculosis of 1.0 - 5.0 ug/mL, it was considered that oral dosing at 30 mg/kg should provide adequate serum concentrations for treatment in elephants. However, rectally administered ethambutol (30 mg/kg) appeared to irritate the rectal mucosa; elephants dosed rectally produced mucus and expelled the rectal contents after one to two hours. Absorption was rapid (faster than following oral administration), with Tmax at the time of the first blood sample (0.5 - 1 hr post dosing), followed by a biexponential decline in drug concentration. There was an apparent lower bioavailability; lack of collection of data at under 0.5 h post dosing, as well as expulsion of the drug from the rectum, may have been responsible. Repeated rectal administration resulted in faster expulsion and attempts to buffer with methylcellulose were ineffective. Rectal administration did not appear to be an appropriate route for this drug in elephants. (J289.28.w1)

The following information is taken with permission directly from the Elephant Care International website (W580.Sept2005.w4):


Note: Detailed guidelines for the treatment of tuberculosis in elephants have been developed in the U.S.A. by the National Tuberculosis Working Group for Zoo and Wildlife Species. The drugs and dosages recommended are based on human treatment protocols and information obtained from pharmacokinetic studies in elephants (unpublished data). The reader is advised to consult the current Guidelines available at the following websites:\protodoc_files\new03\Guidelines For The Control Of Tuberculosis In Elephants 2003.pdf

a) Ethambutol 30 mg/kg administered orally only. In limited studies, pure drug has been found to be irritating to the rectum and is rapidly expelled (Natl. TB Working Group).

Elephant References: 

a) The National Tuberculosis Working Group for Zoo and Wildlife Species. 2003. Guidelines for the Control of Tuberculosis in Elephants. Internet links above.


Great Apes

  • Adult Pan troglodytes - Chimpanzee: Initially 15 mg/kg per day orally, then 25 mg/kg per day orally. (W768.Jun2012.w1)
  • Primates: 22 mg/kg orally once daily . For treatment of mycobacteriosis, in multi-drug therapy together with Isoniazid and Rifampin. (D425.3.15.w3o)


  • Ethambutol (Myambutol, Lederle, 30 mg/kg daily) plus Rifampin (Rifadin, Marion Merrell Dow, Inc., 30 mg/kg twice daily, later increased to 45 mg/kg once daily) given to a Grus americana - Whooping crane for several months for treatment of Avian Tuberculosis, with apparent successful treatment but recrudescence about 10 months after cessation of treatment. (P87.7.w9)
    • TOXIC EFFECT: Treatment with Azithromycin (Pfizer Laboratories Inc.) at 20 mg/kg once daily in food, then increased to 40 mg/kg after one week, was supplemented with ethambutol (30 mg/kg daily) after 16 weeks; three weeks later the crane was found collapsed, deteriorated despite supportive treatment, and was euthanased. Severe chronic active fibrosing cardiomyopathy and severe hepatopathy were present, suggestive of a toxic reaction. (P87.7.w9)
Taxa Groups (hyperlinked if included as Wildpro Modules) containing host species which have been recorded as infected by this organism.
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