RT Journal
A1 Roussel R, Bhatt DL, Steg P, et al
T1 Levels of evidence needed for changing indications, contraindications, and food and drug administration labeling: The case of metformin—reply
JF Archives of Internal Medicine
JO Archives of Internal Medicine
YR 2011
FD June 13
VO 171
IS 11
SP 1042
OP 1043
DO 10.1001/archinternmed.2011.225
UL http://dx.doi.org/10.1001/archinternmed.2011.225
AB 
We are aware of previous well-conducted observational studies by Eurich and others evaluating the safety of metformin in patients with HF patients, and we believe that the changes in product monographs of metformin, down-toning the contraindication of the drug in diabetic patients with stable HF are welcome. Our results extend the basis of these labeling changes, but they also provide indications that other contraindications, such as renal insufficiency, may not be as justified as previously believed. Moreover, the issue is not only to mitigate contraindications, but possibly to switch some of them to indications—a tempting prospect for subjects with HF and diabetes, for example, that cannot be achieved without the highest level of evidence.