Every TB patient positive for HIV is eligible to receive anti-retroviral treatment (ART). With the increasing prevalence of TB/HIV Co infection, there may be need for infected patients to be treated concurrently with anti-tuberculosis and antiretroviral drugs.
The major problem in the concurrent treatment of TB/HIV infections is the negative interaction between rifampicin (the cornerstone of DOTS) and some anti-retroviral drugs, notably the protease inhibitors and non-nucleotide reverse transcriptase inhibitors (NNRTI’S).
Rifampicin is a powerful inducer of cytochrome metabolism of protease inhibitors and NNRTI’S (except efavirenz), and therefore lowers their serum concentration when given concurrently.
In the management of tuberculosis in HIV positive cases, it is therefore, important to bear this in mind and so avoid the concurrent administration of rifampicin and such drugs eg. Nevirapine. Since rifabitin has similar action on tubercle bacilli as rifampicin but with less adverse interaction with the anti retroviral drugs, it can be used as an equivalent alternative for refampicin in TB/HIV infected patients. Thiazetazone should also not be used because it is associated with risk of severe and sometimes fatal skin reactions in HIV infected patients.
Generally, WHO recommends that Co-infected TB/HIV patients complete their TB therapy before they are commenced on ART unless there is a high risk of death during the period of TB treatment such as in patients with very low CD4 count or presence of disseminated tuberculosis.
WHO recommendation for management of individuals with TB diseases and HIV Co-infection.
CD4 > 200/mm3: Start TB treatment, start ART as soon as TB treatment is tolerated (between 2 weeks and 2 months).