Review Article

Clinical Pharmacokinetics

, Volume 53, Issue 6, pp 489-507

Treatment Optimization in Patients Co-Infected with HIV and Mycobacterium tuberculosis Infections: Focus on Drug–Drug Interactions with Rifamycins

  • Mario RegazziAffiliated withUnit of Clinical and Experimental Pharmacokinetics, Foundation IRCCS Policlinico San Matteo Email author 
  • , Anna Cristina CarvalhoAffiliated withInstitute of Infectious and Tropical Diseases, WHO Collaborating Centre for TB/HIV Co-infection, University of BresciaLaboratory of Innovations in Therapies, Education and Bioproducts (LITEB), Oswaldo Cruz Institute (IOC), Oswaldo Cruz Foundation (Fiocruz)
  • , Paola VillaniAffiliated withUnit of Clinical and Experimental Pharmacokinetics, Foundation IRCCS Policlinico San Matteo
  • , Alberto MatteelliAffiliated withInstitute of Infectious and Tropical Diseases, WHO Collaborating Centre for TB/HIV Co-infection, University of Brescia

Rent the article at a discount

Rent now

* Final gross prices may vary according to local VAT.

Get Access

Abstract

Tuberculosis (TB) and HIV continue to be two of the major causes of morbidity and mortality in the world, and together are responsible for the death of millions of people every year. There is overwhelming evidence to recommend that patients with TB and HIV co-infection should receive concomitant therapy of both conditions regardless of the CD4 cell count level. The principles for treatment of active TB disease in HIV-infected patients are the same as in HIV-uninfected patients. However, concomitant treatment of both conditions is complex, mainly due to significant drug–drug interactions between TB and HIV drugs. Rifamycins are potent inducers of the cytochrome P450 (CYP) pathway, leading to reduced (frequently sub-therapeutic) plasma concentrations of some classes of antiretrovirals. Rifampicin is also an inducer of the uridine diphosphate glucuronosyltransferase (UGT) 1A1 enzymes and interferes with drugs, such as integrase inhibitors, that are metabolized by this metabolic pathway. Rifampicin is also an inducer of the adenosine triphosphate (ATP) binding cassette transporter P-glycoprotein, which may also lead to decreased bioavailability of concomitantly administered antiretrovirals. On the other side, rifabutin concentrations are affected by the antiretrovirals that induce or inhibit CYP enzymes. In this review, the pharmacokinetic interactions, and the relevant clinical consequences, of the rifamycins—rifampicin, rifabutin, and rifapentine—with antiretroviral drugs are reviewed and discussed. A rifampicin-based antitubercular regimen and an efavirenz-based antiretroviral regimen is the first choice for treatment of TB/HIV co-infected patients. Rifabutin is the preferred rifamycin to use in HIV-infected patients on a protease inhibitor-based regimen; however, the dose of rifabutin needs to be reduced to 150 mg daily. More information is required to select optimal treatment regimens for TB/HIV co-infected patients whenever efavirenz cannot be used and rifabutin is not available. Despite significant pharmacokinetic interactions between antiretrovirals and antitubercular drugs, adequate clinical response of both infections can be achieved with an acceptable safety profile when the pharmacological characteristics of drugs are known, and appropriate combination regimens, dosing, and timing of initiation are used. However, more clinical research is needed for newer drugs, such as rifapentine and the recently introduced integrase inhibitor antiretrovirals, and for specific population groups, such as children, pregnant women, and patients affected by multidrug-resistant TB.