Efficacy of isoniazid prophylaxis in renal allograft recipients

The efficacy of isoniazid (INH) prophylaxis in renal allograft recipients who are on long-term immunossupression in a region highly prevalent for tuberculosis (TB) was studied. INH (300 mg/d in patients weighing more than 35 kg and 5 mg/kg/d in patients with < 35 kg body weight) together with Pyridoxine 50 mg/d for 1 year was started in randomly assigned renal allograft recipients. Occurence of clinical tuberculosis during the initial 2 years posttransplantation was observed in the risk group and patients at no risk. Risks were defined as acute rejection episodes and exposure to antirejection therapy, past history of TB completely or incompletely treated, radiological evidence of past tuberculosis, history of tuberculosis in close contacts. Among 480 patients registered in the study, INH prophylaxis was given to 219 randomly assigned renal allograft recipients. Results were compared among patients developing TB during the initial 2 years posttransplantation in both the groups. Risk factors were analyzed for comparison in both groups. No significant difference was observed in terms of past history of TB, TB in close contacts, episodes of acute rejection during the initial 3 months, and comorbidities such as cytomegalovirus infection, hepatitis C virus infection, and posttransplant diabetes. One patient from the INH group and 10 patients from the non-INH group developed TB during the initial 2 years posttransplantation (P <.0001). None of patients required discontinuation of INH. INH was observed to be safe and effective as a chemoprophylactic agent in renal allograft recipients.