Continuation or termination of metformin in diabetic patients exposed to iodinated contrast medium?

Mohamad Ali Dayani

doi:10.15171/jrip.2019.34

Abstract

Lactic acidosis (LA) secondary to metformin administration is a rare incident with a very highmortality rate (≥50%). Hypoxia has been suggested to contribute to metformin-associatedlactic acidosis (MALA) in 90% of patients developing this condition. In susceptible patientssuch as those with renal insufficiency, the level of plasma metformin is increased particularlyafter exposure to iodinated contrast media (ICM). One major concern in patients with renalinsufficiency is to adjust the metformin dose based on the renal functional capacity prior to ICMexamination. In this review, we assessed metformin tolerable threshold in diabetic patients withrenal failure. We also reviewed metformin withdrawal criteria in patients with chronic kidneydisease (CKD) exposed to intravenous ICM during angiography. Our results indicated that inpatients with insufficient renal function (i.e. 30< estimated glomerular filtration rate(eGFR) <60and 30<eGFR<45 mL/min/1.73 m2), or those with acceptable renal function (eGFR ≥60 mL/min/1.73 m2) and concomitant comorbidities, the decision to withhold or reinitiate metforminshould be based on patient’s medical condition.

Highlights

Lactic acidosis (LA) is a marker of inadequate tissue perfusion and oxygen supply
The intensity of hypoxia; and not the lactate or metformin concentrations, predicts the mortality rate in patients, and metformin administration must be reconsidered in the presence of tissue hypoxia [12]
Diabetic patients are at risk of LA following metformin administration

Summary

Introduction

Lactic acidosis (LA) is a marker of inadequate tissue perfusion and oxygen supply. Insufficient oxygen delivery triggers anaerobic metabolism which transforms pyruvate to lactate [1]. The intensity of hypoxia; and not the lactate or metformin concentrations, predicts the mortality rate in patients, and metformin administration must be reconsidered in the presence of tissue hypoxia [12]. A recent study has clarified no association between metformin administration and LA; this indication may not be applicable to susceptible individuals with metformin overdose [13]. Reduced kidney function and metformin clearance are the most significant risk factors of MALA In this regard, diabetic patients are at risk of LA following metformin administration. Other risk factors of MALA include reduced tissue oxygenation (such as in heart failure, hypoxemia, ICM exposure, sepsis and shock), as well as disturbed lactate metabolism (such as in alcoholism, or liver fibrosis) (Table 1) [5]. It is highly recommended to avoid metformin administration in these contraindicated conditions

Materials and Methods

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Conclusion