High doses of riboflavin and thiamine, also known as vitamins B1 and B2, may be useful in the prevention of secondary hyperlactatemia, according to a letter and editorial comment in the July 17 issue of the Aids Reader, published at the Medscape HIV/AIDS website.
In the letter, two doctors from Case Western Reserve University, Cleveland, Ohio, document their experience with two heavily pretreated patients who suffered symptomatic high lactate levels whilst on combination therapy which included the nucleoside analogues (NRTIs) stavudine and/or didanosine. NRTIs - especially stavudine, zalcitabine, zidovudine and didanosine - are thought to have the greatest potential for mitochondrial toxicity, which often manifests as symptomatic hyperlactatemia (progressive fatigue and/or nausea and/or abdominal pain) and, more seriously, lactic acidosis.
Both patients - a 37 year-woman and a 72 year-old man - discontinued antiretrovirals for four weeks and began taking 100 mg B1 and 50 mg B2 daily. Symptoms improved progressively, and four weeks later both patients restarted their NRTI-containing regimens with no recurrence of hyperlactatemia and successful suppression of viral load.
In an related editorial penned by Helene Coté and Julio Montaner of the British Columbia Centre For Excellence, Vancouver, the authors review the current clinical management of lactic acidosis. Until clinical trials provide a more definitive answer, they say, the most obvious approach is to change to an NRTI-sparing regimen. However, in heavily pretreated patients, this is not always viable. Since in vitro evidence and anecdotal reports suggest that vitamins B1 and B2, as well as L-carnitine and alpha lipoic
(thiotic) acid may alleviate symptoms of mitochondrial toxicity.
Since there is no evidence that such supplementation leads to serious adverse effects, the authors cautiously endorse the use of treatment interruption and the use of vitamins or supplements for the management of NRTI-associated hyperlactatemia and lactic acidosis when NRTI-sparing regimens are not feasible.