Visual Examination Frequency for People Taking Ethambutol for Tuberculosis

In Canada, a recommended treatment for active tuberculosis (TB) disease includes a regimen of isoniazid, rifampin, pyrazinamide, and ethambutol. A common adverse effect of ethambutol is eye toxicity (i.e., visual impairment), which can cause changes in visual acuity, visual fields, and colour vision. Given this side effect of ethambutol, there is an interest in knowing whether there is any guidance regarding monitoring for these adverse effects in people taking ethambutol as part of treatment for active TB disease. In June 2020, CADTH searched the literature for evidence-based guidelines regarding the frequency of visual examination for people taking ethambutol as part of a TB treatment. This report identified 5 evidence-based guidelines that met the inclusion criteria based on their title and abstract. The purpose of the current report is to review the full texts of these guidelines and to summarize and critically appraise the eligible publications. This report is a component of a larger CADTH condition-level review on TB. A condition-level review is an assessment that incorporates all aspects of a condition, including prevention, detection, treatment, and management. For more information on CADTH’s condition-level review on TB, please visit the project page (https://www.cadth.ca/tuberculosis).