Lactic acidosis and anti-retroviral drugs.

(1) Lactic acidosis is a serious, often fatal adverse reaction to nucleoside HIV reverse transcriptase inhibitors. (2) The presenting symptoms are non specific, and include gastrointestinal upset, fatigue, fever, and breathlessness. They appear gradually after several weeks or months of antiretroviral treatment. (3) Moderate hyperlactataemia, with few if any symptoms, is common in patients taking nucleoside inhibitors, and is not predictive of severe lactic acidosis. (4) Cases of lactic acidosis were reported in newborns whose mothers were given nucleoside inhibitors to reduce the risk of mother to child transmission of HIV. (5) In practice, hyperlactataemia should be suspected in patients taking antiretroviral drugs who present with unexplained symptoms, and especially breathlessness. Elevated lactataemia (especially above 5 mmol/l) requires rapid withdrawal of antiretroviral treatment.