TB Medication Contraindications and Interactions

Absolute Contraindications Between TB and HIV Medications

• The Centers for Disease Control and Prevention (CDC) guidelines permit rifabutin use with ritonavir at substantially reduced doses, instead of the standard 300 mg daily dose, to avoid contraindications 1, 2

Permitted Combinations (Not Contraindicated)

• The CDC recommends that rifampin can be used with specific antiretroviral regimens, such as efavirenz plus two NRTIs, ritonavir (alone) plus one or more NRTIs, and ritonavir combined with saquinavir as dual protease inhibitor therapy 1, 4
• All nucleoside reverse transcriptase inhibitors (NRTIs) have no contraindication with any rifamycin because they are not metabolized by CYP450, according to the CDC guidelines 1, 2

TB Medications Without Contraindications

• The CDC states that isoniazid, pyrazinamide, ethambutol, and streptomycin have no contraindications with protease inhibitors, NNRTIs, or NRTIs, as these first-line TB drugs are not CYP450 inducers 3

Critical Clinical Pitfalls

• The CDC advises to remember the 2-week washout period after rifampin discontinuation, as its enzyme-inducing effects persist for at least 2 weeks, and protease inhibitors or NNRTIs should not be started until 2 weeks post-rifampin 5, 6
• The American Thoracic Society recommends prioritizing TB treatment over HIV treatment modifications, as active TB requires immediate, uncompromised treatment with rifampin-containing regimens for optimal morbidity and mortality outcomes 4