Current guidelines recommend 6 to 12 months of treatment with INH for purified protein derivative (PPD)-positive individuals. Problems with this treatment include compliance, adverse reaction, and the possibility of not preventing disease due to INH-resistant organisms. Studies suggest that two or three months of rifampin and pyrazinamide may be more effective than longer courses of INH. A two-month prevention course should help to increase compliance. In addition, the use of two drugs (rifampin and pyrazinamide) may help overcome problems with drug resistance.