Ethambutol toxicity: Expert panel consensus for the primary prevention, diagnosis and management of ethambutol-induced optic neuropathy

Ethambutol use may lead to permanent vision loss by inducing a dose- and duration-dependent optic neuropathy. This has been of concern to ophthalmologists and physicians both; however, ethambutol continues to be used because of its anti-mycobacterial action with relative systemic safety. Recently, the guidelines of the Revised National Tuberculosis Control Programme of India have been revised to allow for fixed dose and longer duration of ethambutol use; this is likely to result in an increase in vision-threatening adverse effects. Taking cognizance of this, neuro-ophthalmologists, infectious disease specialists, and scientists met under the aegis of the Indian Neuro-Ophthalmology Society to deliberate on prevention, early diagnosis, and management of ethambutol-related toxic optic neuropathy. The recommendations made by the expert group focus on early suspicion of ethambutol toxicity through screening at the physician's office and opportunistic screening by the ophthalmologist. Further, they focus on an early diagnosis through identification of specific clinical biomarkers and on management in way of early stoppage of the drug and supportive therapy. This statement also describes the mechanism of reporting a case of toxic optic neuropathy through the Pharmacovigilance Programme of India and emphasizes the need for spreading awareness regarding vision-threatening adverse effects among patients and healthcare workers.