On June 6, 2007, the drug Actos was issued a “black box” warning that the drug might trigger heart failure. Although this warning has been issued, the warning actually has nothing to do with Actos itself but just the class of drugs that it is associated with (which includes Avandia).
Avandia and Actos inrease the tendency for the body to accumulate fluids due to an inadequate pumping of the heart (which is a complication of diabetes). This kind of inadequate pumping can result in heart failure.
Although there is still much debate on whether or not Avandia and Actos do indeed cause heart failure, it is good to know the risks and to consult your doctor