Isoniazid-associated hepatitis--serum enzyme determinations and histologic features.

A prospective study of 208 patients treated for up to 12 months with isoniazid (INH((R))) for tuberculosis prophylaxis was made. Levels of serum glutamic oxaloacetic acid transaminase (SGOT) became elevated in 20 percent of the adults followed and in 30 percent predominantly nonspecific symptoms developed, in 11 percent simultaneously with SGOT elevation; SGOT levels became elevated in two of 33 children and 1 was symptomatic. Mild SGOT elevations in asymptomatic adults were self-limited; however, a small percentage of symptomatic adults showed prolonged SGOT elevation for months after INH was completed. Results of liver biopsy studies in the early stages of SGOT elevation generally showed portal and periportal lymphocytic infiltrations with lesser numbers of plasma cells, neutrophils and eosinophils.