South African National Antiretroviral Therapy Guidelines 2004 and 2010.

1D4T could be substituted for AZT in case of toxicity; EFV or NVP chosen dependent on pregnancy risk, EFV chosen when patients receive concurrent rifampicin for tuberculosis. Over time a gradual move to prefer EFV as data suggest that risk to foetus is small. 3TDF replaced by AZT if contra-indicated (e.g. kidney disease). 4Based on data that most children with virologic failuire of a LPV/r first-line regimen have inadequate adherence and no LPV associated resistance, blanket switching is not indicated.
Patients who were still on D4T by the time of the 2010 regimen guidelines could remain on D4T if they did not experience toxicity. However, practically the threshold for switching for lypodystrophy or other side effects is generally low.