Metformin and radiocontrast dye
Why should we stop using metformin before a radiocontrast image? And what are the proofs that lactic acidosis or other complications may be exacerbated by this action? If we have to stop it, is it for every diabetic patient before imaging? Thank you
The reason we stop metformin is because there is an increased risk of lactic acidosis. The reason for this is that radiocontrast dyes are shown to cause acute renal failure. Since metformin is cleared virtually exclussivley by renal mechanisms, this may cause increased concentrations of metformin, leading to lactic acidosis. The fact that the patient is a diabetic is irrelevant to whether you d/c the drug or not. If they take metformin, whether it be for diabetes, weightloss or anything else, you stop metformin 48 hours before and wait 48 hours after radiocontrast before reinitiaing metformin therapy. Hope this helps!
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Thx for replying! I was thinking with the same logic but the fact is that I haven't seen in any reference that radiocontrast agents can "CAUSE" acute renal failure, they are however contraindicated (or used with pecaution) in cases of renal failure that is already present, because their clearance is retarded. But whether they can cause the renal failure am not sure about it. If it was the case, all treatments that are eliminated by kidneys (which are many) must be stopped before every radiocontrast imaging to prevent intoxication, and not only Metformin. Thanks again for ur reply, it makes a good medical discussion!