Isoniazid chemoprophylaxis. Association with detection and incidence of liver toxicity

Abstract

The hepatotoxicity of isoniazid was studied in a double blind fashion in 120 adult patients receiving the drug for chemoprophylaxis. The incidence of abnormal SGOT [serum glutamic-pyruvic transaminase] values was significantly higher in those on the drug, 18.3% having elevated values as compared to 6.7% of those on placebo during the 3-mo. study period. There was no statistical difference in frequency of symptoms suggestive of liver diseases between isoniazid and placebo groups. There was no significant relationship between symptoms and elevated SGOT. Symptomatology does not appear to be a sensitive method for detecting early isoniazid liver toxicity. Biochemical monitoring appeared to detect liver toxicity at an earlier and more reversible stage. Isoniazid was used very extensively in therapy of tuberculosis for the first 20 yr after it became available with only rare instances of associated hepatotoxicity noted.