Metformin-associated lactic acidosis in an older adult after colonoscopy: an uncommon trigger for a rare complication

Preparing for Colonoscopy in People with Diabetes: A Review with Suggestions for Clinical Practice

People with diabetes have an increased risk of adverse events during the peri-colonoscopy period, including hypoglycemia, lactic acidosis, diabetic ketoacidosis and acute kidney injury. This is secondary to inadequate dietary modification, the bowel preparation and antihyperglycemic agent modification. With the availability of many new diabetes agents, endoscopists need updated guidance. This review of current literature provides a practical approach to antihyperglycemic agent modification in the context of colonoscopy preparation, as well as guidelines on dietary changes, the bowel preparation itself and glucose monitoring.

The Association between Metformin Therapy and Lactic Acidosis

INTRODUCTION AND OBJECTIVES

There is increasing evidence to suggest that therapeutic doses of metformin are unlikely to cause lactic acidosis. The aims of this research were (1) to formally evaluate the association between metformin therapy and lactic acidosis in published case reports using two causality scoring systems, (2) to determine the frequency of pre-existing independent risk factors in published metformin-associated lactic acidosis cases, (3) to investigate the association between risk factors and mortality in metformin-associated lactic acidosis cases, and (4) to explore the relationship between prescribed metformin doses, elevated metformin plasma concentrations and the development of lactic acidosis in cases with chronic renal impairment.

METHODS

A systematic review was conducted to identify metformin-associated lactic acidosis cases. Causality was assessed using the World Health Organisation-Uppsala Monitoring Centre system and the Naranjo adverse drug reaction probability scale. Compliance to dosing guidelines was investigated for cases with chronic renal impairment as well as the association between steady-state plasma metformin concentrations prior to admission.

RESULTS

We identified 559 metformin-associated lactic acidosis cases. Almost all cases reviewed (97%) presented with independent risk factors for lactic acidosis. The prescribed metformin dose exceeded published guidelines in 60% of cases in patients with impaired kidney function. Metformin steady-state plasma concentrations prior to admission were predicted to be below the proposed upper limit of the therapeutic range of 5 mg/L.

CONCLUSIONS

Almost all cases of metformin-associated lactic acidosis reviewed presented with independent risk factors for lactic acidosis, supporting the suggestion that metformin plays a contributory role. The prescribed metformin dose, on average, exceeded the dosing recommendations by 1000 mg/day in patients with varying degrees of renal impairment but the predicted pre-admission plasma concentrations did not exceed the therapeutic range.

Antihyperglycemic therapy during colonoscopy preparation: A review and suggestions for practical recommendations

Patients with diabetes have distinct risks during precolonoscopy bowel preparation, caused by change of diet, change of antihyperglycemic medication regimens and diabetes-related complications and comorbidities. These risks include hypoglycemia, water and electrolyte imbalance, acute renal failure, lactic acidosis, ketoacidosis and low quality of bowel preparation. Here we review the existing literature and present recommendations from a subcommittee of the Israeli National Diabetes Council for primary care physicians and gastroenterologists. The instructions include general suggestions on diet and glucose monitoring and specific recommendations on timing of modification or cessation of each of the antihyperglycemic medication types to ensure patient safety during bowel preparation.

Novel 4-heteroaryl-antipyrines as DPP-IV inhibitors

Type 2 diabetes mellitus is a vast growing progressive disease that almost affects one person among every twelve globally. Regardless the availability of wide variety of oral hypoglycemics, only one-third of patients achieves proper glycemic control. With the advantage of the low risk of hypoglycemia, DPP-IV attracted the attention of medicinal chemists as a new target for oral hypoglycemics. In this report, a lead compound 1, with antipyrine scaffold, was obtained, and its binding mode was calculated. Several derivatives with bridged nitrogenous heterocycles have been synthesized via multicomponent reaction under controlled microwave heating conditions. The antidiabetic activity versus DPP-IV protein was evaluated and compared with sitagliptin. Compounds with smaller- or medium-sized nitrogenous bridges were comparable with sitagliptin in terms of DPP-IV inhibitory activity, potentially via targeting Glu203 and Glu204. The oral hypoglycemic activities of compounds with submicromolar IC50 values were further evaluated using diabetic mouse model.