Safety of Contrast Agents Administration in Patients with Type 2 Diabetes Mellitus During Metformin Intake

Metformin is a sugar-lowering drug that is actively used in long-term therapy of type 2 diabetes mellitus (DM2). The safety of metformin for different groups of DM2 patients is currently well studied. However, the drug is contraindicated for patients with severe renal impairment and should be used with caution in cases of moderate renal impairment. Since contrast agents as well as metformin are excreted by kidneys, patients with reduced renal function taking metformin require special attention due to the risk of lactic acidosis, a life-threatening condition resulting from functional renal failure and accumulation of metformin in tissues. Numerous studies have shown that the risk of lactic acidosis is relatively low and in most cases is not associated with metformin therapy per se, but rather with comorbidities. Initial versions of clinical recommendations related to the use of contrast agents strictly limited the use of metformin before and after examination, but as data on lactate acidosis and possible causes of this condition expanded, the recommendations gradually became less strict. For emergency contrast studies, they are currently unchanged, but data are gradually accumulating on the safety of continuing metformin in these clinical situations. There is no consensus among contrast manufacturers on whether and in what regimen metformin should be interrupted during contrast studies as well as on a number of other related issues. The best strategy for clinicians is to check the instructions for each specific drug before use.