Which tuberculosis medication is contraindicated in patients taking protease inhibitors?

Rifampin is the tuberculosis medication that is contraindicated in patients taking protease inhibitors. The reason for this contraindication lies in the interaction between rifampin and the protease inhibitors, which are commonly used in the treatment of HIV.

Rifampin is a potent inducer of cytochrome P450 enzymes, particularly CYP3A4. This induction can lead to decreased concentrations of protease inhibitors in the body, significantly reducing their effectiveness. This interaction is particularly concerning because maintaining adequate levels of protease inhibitors is critical for effectively managing HIV in patients who are co-infected with tuberculosis.

Therefore, using rifampin in such cases could lead to suboptimal treatment outcomes for HIV, potentially resulting in increased viral load and disease progression. Alternatives like rifabutin, which has a much less potent effect on CYP450 enzymes, may be used instead in co-infected patients to avoid these interactions.

Understanding the pharmacokinetic interactions and the critical nature of maintaining effective drug levels in HIV therapy is essential in treating patients with both HIV and tuberculosis.