ObjectiveOur first objective was to determine a blood lactate threshold predictive of survival in human immunodeficiency virus patients experiencing lactic acidosis related to nucleoside analogs, and second, to test l-carnitine for the treatment of patients exceeding that threshold.Designa) Retrospective study using data from personal and published observations to determine the lactate threshold between survivors and nonsurvivors in human immunodeficiency virus patients being treated with nucleoside analogs. b) Prospective multicenter open trial to test l-carnitine treatment of human immunodeficiency virus patients receiving nucleoside analogs.SettingMedical intensive care units of four teaching hospitals and one general hospital.PatientsRetrospective analysis of data from 39 human immunodeficiency virus patients (five personal cases and 34 patients from the literature) receiving nucleoside-analog treatment from which lactate values were available. An additional six patients with high lactate values were included as a pilot study testing the use of l-carnitine therapy.Measurements and Main ResultsAn initial lactate level of 9 mmol/L, which gave good positive and negative predictive values, was determined as a threshold between survivors and nonsurvivors for the patients receiving nucleoside-analog treatment. Six patients with initial lactate levels >10 mmol/L were prospectively treated with l-carnitine; three survived beyond the end of the study.ConclusionsThe blood lactate levels in human immunodeficiency virus patients receiving nucleoside-analog therapy can predict mortality in these patients. The preliminary data from this pilot study suggest that l-carnitine may be helpful for patients who have nucleoside-analog-related lactic acidosis with blood lactate levels >10 mmol/L. Further studies will be necessary to affirm the therapeutic efficacy of l-carnitine in this setting.