The increased risk of developing
tuberculosis (TB) among those infected with HIV has prompted a need to reconsider the institution of preventive
therapy/
chemoprophylaxis with one or more antituberculosis drugs. Prior to the initiation of preventive
therapy for
tuberculosis, it is essential to rule out active TB. The target population for
chemoprophylaxis among HIV seropositives includes all Mantoux (
PPD) positive individuals who do not have active
tuberculosis and could include all
PPD negative individuals living in high prevalence region for TB. The optimal duration of preventive
therapy with single
drug isoniazid, daily or twice weekly, should be greater than six months to provide the maximum degree of protection against
tuberculosis. The effectiveness of preventive
therapy should be evaluated at regular intervals by monitoring patients for drug adherence,
drug toxicity and for the development of
tuberculosis. Though the impact of preventive
therapy on an individual basis may be rather small, widespread implementation would have substantial impact on morbidity due to
tuberculosis and some impact on mortality. Till the vast majority of HIV positive individuals in the world can access antiretroviral
therapy, preventive
therapy for
tuberculosis should be offered at voluntary counselling and testing centres, as part of a package of care that includes prophylaxis and treatment of
opportunistic infections,
nutritional support and counselling.