The Food and Drug Administration in the US and the manufacturer of d4T, Bristol Myers Squibb, has issued a warning to healthcare workers that pregnant women taking d4T/ddI may be at increased risk of the life-threatening condition lactic acidosis. Three pregnant women taking d4T/ddI developed lactic acidosis, with or without pancreatitis, and died.
Lactic acidosis occurs when cells of the body are unable to convert food into usable energy. As a result, excess acid accumulates in the body and vital organs such as the liver or pancreas may be damaged. Severe lactic acidosis is an infrequent, but well-described complication of the class of HIV drugs known as nucleoside analogues
Several other women taking this dual nucleoside combination have also developed lactic acidosis, with or without pancreatitis. Cases were identified through clinical trials or post-marketing surveillance. Experts do not know if pregnancy potentiates known side-effects of d4T/ddI, or if combinations of other nucleoside analogues also carry an increased risk of lactic acidosis during pregnancy.
In view of these findings, the company has recommended that it may be better not to use ddI/d4T during pregnancy, except in cases where women already have resistance (or cannot tolerate) the other nucleoside analogues available.