Antiretroviral therapy is recommended for all patients with TB with a CD4 count <200 cells/mm³ and should be considered for TB patients with CD4 <350 cells/mm3. Treatment of TB remains a central priority for patient management and should not be compromised by ART. On the other hand, case fatality rates in many patients with TB during the first two months of TB treatment are high in particular when they present with advanced HIV disease, and ARV in this setting might be life-saving.
Patients with TB merit special consideration because co-management of HIV and TB is complicated by Rifampicin drug interactions with NNRTIs and PIs, pill burden, adherence and drug toxicity. Taking the available data into account, the first line treatment recommendation for patients with TB and HIV co-infection is (AZT or d4T) + 3TC+ EFZ. The 800 mg dose of EFZ achieves higher drug levels comparable to those seen in the absence of Rifampicin and thus may reduce the chance of HIV drug resistance, but also can increase the toxicity risk.
SQV/r in combination with the NRTI backbone is an alternative to EFZ although resistance is a clear risk with suboptimal adherence. ABC is another alternative to EFZ with the advantage of low pill burden, has no interaction with Rifampicin, and has the advantage of being able to be given to children under 3 years of age for whom appropriate EFZ dosing information is not yet available.
The following two scenarios summarise the management of patients co-infected with HIV and TB:
Patient develops tuberculosis while on antiretroviral therapy:
Antiretroviral therapy should be continued throughout TB treatment, with changes as follows:
First line drugs: Substitute Nevirapine for Efavirenz. If this is not possible (e.g. intolerant of Efavirenz or significant risk of falling pregnant), Nevirapine may be substituted with Abacavir or Saquinavir/ritonavir.
Second line drugs: Lopinavir/ritonavir should be changed to Saquinavir/ritonavir (dose: 400/400 mg every 12 hours - 3 extra caps of ritonavir). This should be continued until 2 weeks after completion of TB treatment, when the extra ritonavir can be stopped.