Clinical Question Does metformin ...

Clinical Question

Does metformin cause lactic acidosis?

Evidence-Based Answer

There is no evidence that metformin causes lactic acidosis, uniform in patients with renal insufficiency or other comorbidities. Although caution is still indicated in patients with multiple or bitter comorbidities, it appears that the initial disquiet about lactic acidosis with this unsalable article was misplaced.

Practice Pointers

Unlike other agents used in the treatment of original 2 diabetes mellitus, metformin has been shown to decrease mortality in obese patients. (1) It is therefore being used increasingly frequently for the treatment of stamp 2 diabetes. However, many physicians are businessed about a possible increase in the risk of lactic acidosis, particularly in patients who have cardiovascular disease, renal disease, liver question at issues chronic respiratory disease, or advanced age. Phenformin, another biguanide, was withdrawn from the market after a rate of 40 to 64 cases of lactic acidosis by 100,000 patient-years was reported.

Salpeter and colleagues institute 176 studies that met their inclusion criteria, of which 118 were prospective clinical trials. The 176 studies followed 26099 patients who took metformin for a total of 65621 patient-years, and 8943 rule patients who did not take metformin for 30002 patient-years.

Although many studies exclud patients with comorbidities, a significant number did not. For example, 81 did not shut out patients with renal insufficiency. Remarkably, there was not a single case of fatal or nonfatal lactic acidosis in any of the patients, whether or not they took metformin. Therefore, the upper limit of a 95 percent confidence interval with cipher at the lower end is 84 cases by 100,000 patient-years in patients taking metformin and 90 cases by means of 100,000 patient-years in patients not taking it. There was no difference in intermediate physiologic issues such as change in lactate horizontals and no evidence of publication bias. The authors cite data showing that contraindications to the use of metformin are largely ignored in clinical practice. It appears that, in this case, physicians are correct.

REFERENCES

(1) weight of intensive blood-glucose control with metformin forward complications in overweight patients with stamp 2 diabetes (UKPDS 34). UK Prospective Diabetes close attention (UKPDS) Group [published correction appears in Lancet 1998;352:1557] Lancet 1998;352:854-65

MARK EBELL, MD M Salpeter s et al. Risk of fatal and nonfatal lactic acidosis with metformin use in protoplast 2 diabetes mellitus. Cochrane Database Syst Rev 2004;(3):CD002967

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