American Board of Internal Medicine (ABIM) Certification Practice Exam

What is a common recommendation before starting ethambutol treatment?

1. Assessment of liver function

2. Evaluation of renal clearance

3. Evaluation of color discrimination and visual acuity

4. Blood pressure monitoring

The correct answer is: Evaluation of color discrimination and visual acuity

Before beginning treatment with ethambutol, it is essential to evaluate color discrimination and visual acuity. Ethambutol is an antibiotic primarily used to treat tuberculosis, and one of its notable side effects is the potential for ocular toxicity, specifically retrobulbar optic neuritis. This condition can lead to diminished visual acuity and changes in color vision, such as loss of red-green discrimination. Therefore, conducting a baseline assessment of a patient’s visual status helps establish a reference point for monitoring any adverse effects that may arise during treatment. Regular follow-up assessments are critical, especially if the patient is receiving prolonged therapy. While monitoring liver function and renal clearance are also relevant considerations in the management of patients on various medications, they are not specifically highlighted in the clinical guidelines for ethambutol initiation. Blood pressure monitoring, although important in many contexts, is not directly associated with the commencement of ethambutol therapy or its side effect profile.