Ethambutol 400mg Tablets – Summary of Product, Side Effects

Myambutol is an antibiotic primarily used to stop the growth of tuberculosis infection in patients positively diagnosed with TB.

It’s also known as Ethambutol (generic).

What it Does

Myambutol is an oral chemotherapeutic agent that’s proven to be particularly effective in treating Mycobacterium infections. It is specifically used in the treatment of tuberculosis caused by the bacterium M. tuberculosis. It is used in conjunction with other tuberculosis-treating drugs, including cycloserine, ethionamide, pyrazinamide, viomycin, Isoniazind, aminosalicylic acid, and streptomycin.

It can be used in the treatment of other conditions as indicated by a physician.

Active Ingredients


Ethambutol acts as a bacteriostatic agent designed to obstruct the growth of M. tuberculosis. It acts by obstructing the formation of the cell wall.

Side Effects

The most severe side effect that accompanies prolonged use of Myambutol is a decrease in visual acuity that may result in irreversible blindness. Patients may also experience neuropathies that result in a decrease in visual acuity (the ability to see clearly), scotoma (an area of partially diminished acuity in the patient’s field of vision), color blindness, and/or other visual defects.

Patients taking Myambutol who notice changes in their field of vision, no matter how small, should contact their physician immediately. Vision recovery may be possible after the drug is no longer being taken. Patients with pre-existing vision problems, including glaucoma, color-blindness, cataracts, and near and farsightedness, should be carefully monitored by their opthamologist throughout the course of their treatment, as it can be difficult to differentiate between the pre-existing condition and damage to their visual field caused by Myambutol.

Myambutol allergic reactions have been noted in the form of dermatitis, hypersensitivity, or anaphylaxis. Drug allergies can result in life-threatening conditions and should be mentioned to a physician immediately.

Other side effects include:

  • Rash
  • Nausea and/or vomiting
  • Joint pain
  • Gastrointestinal upset and/or abdominal pain
  • Gout
  • Disorientation
  • Hallucinations
  • Mental confusion
  • Malaise
  • Fever
  • Anorexia

Myambutol has also been associated with fatal liver toxicities and hypersensitivity syndrome, leading to hepatitis, pneumonitis, nephritis, myocarditis, and pericarditis.

Myambutol is not recommended for use in patients under the age of thirteen and should be administered in reduced doses to those with decreased renal function. The effects Myambutol may have on pregnant women and geriatric patients have not been confirmed due to limited studies.