Ethambutol and optic neuropathy.
OBJECTIVE
To demonstrate the association between ethambutol and optic neuropathy.


METHODS
Thirteen patients who developed optic neuropathy after being treated with ethambutol for tuberculosis of the lung or lymph node at Siriraj Hospital between 1997 and 2001 were retrospectively reviewed. The clinical characteristics and initial and final visual acuity were analyzed to determine visual outcome.


RESULTS
All patients had optic neuropathy between 1 to 6 months (mean = 2.9 months) after starting ethambutol therapy at a dosage ranging from 13 to 20 mg/kg/day (mean = 17 mg/kg/day). Seven (54%) of the 13 patients experienced visual recovery after stopping the drug. Of 6 patients with irreversible visual impairment, 4 patients had diabetes mellitus, glaucoma and a history of heavy smoking.


CONCLUSIONS
Early recognition of optic neuropathy should be considered in patients with ethambutol therapy. A low dose and prompt discontinuation of the drug is recommended particularly in individuals with diabetes mellitus, glaucoma or who are heavy smokers.
Chuenkongkaew
W
W
Department of Ophthalmology, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok 10700, Thailand.
Samsen
P
P
Thanasombatsakul
N
N
D000328:Adult; D000995:Antitubercular Agents / Q000009:adverse effects* / Q000627:therapeutic use; D004977:Ethambutol / Q000009:adverse effects* / Q000627:therapeutic use; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009901:Optic Nerve Diseases / Q000139:chemically induced*; D014388:Tuberculosis, Lymph Node / Q000188:drug therapy; D014397:Tuberculosis, Pulmonary / Q000188:drug therapy
D000995:Antitubercular Agents; D004977:Ethambutol