イソニコチン酸ヒドラジドによると思われる視神経障害の1例

A case of presumed optic neuropathy due to isonicotinic acid hydrazide

　副作用の少ないといわれている抗結核薬イソニコチン酸ヒドラジドによる視神経障害の症例を経験した．主な症状として視力低下，中心暗点，中心フリッカー値の低下，視神経乳頭の腫脹が認められた．副作用の発生までの総投与量は1,021g,1日投与量は1.0〜0.7gであった．投与中止後，約40日目から視力は改善しはじめたが，中心暗点は6カ月後でも残存していた．これらはエタンブトール中毒性視神経障害の臨床症状と極めて良く似ているため，両者の鑑別には注意を要することを報告した．

A 58-year-old male had been under treatment for pulmonary tuberculosis for the past 16 years. In the past 27 months, he was treated with isonicotinic acid (INAH) and rifampicin (RFP). The total dosis accummulated to 1,021 g for INAH and 1,467 g for RFP when the patient complained of blurred vision in both eyes. Optic neuritis was diagnosed onaccount of central scotoma, disc hyperemia and decreased flicker fusion frequency. Visual functions gradually improved during the following 2 months after withdrawal of INAH.

The finding seemed to indicate that systemic INAH was responsible for the optic neuropathy.The overall clinical manifestation well resembled that of toxic neuropathy due to systemic etham-butol administration.

Rinsho Ganka (Jpn J Clin Ophthalmol) 41(10) : 1175-1179,1987