Treating patients aged greater than or equal to 35 years for tuberculosis i
nfection has been controversial because of the hepatotoxic effects of isoni
azid. A 2-year retrospective cohort study of outpatient medical records det
ermined the completion rate in this age group and identified risk factors a
ssociated with isoniazid-associated hepatotoxicity. Isoniazid preventative
therapy was well tolerated. However, toxicity occurred in women receiving c
oncomitant medications and men who used alcohol.