Lactic acidosis is the most dramatic manifestation of nucleoside reverse transcriptase inhibitor (NRTI)-associated mitochondrial dysfunction. The optimal management of subjects who recover from an episode of lactic acidosis--or its milder form, symptomatic hyperlactatemia--remains unclear. Most physicians opt to restart NRTI-sparing regimens, but such an option may not be available for heavily antiretroviral-experienced patients. Therefore, there is a need to investigate ways to prevent the recurrence of hyperlactatemia in patients who require NRTI-based therapy.