Renal impairment metformin

Metformin is a biguanide used to treat diabetes mellitus. It is contraindicated in patients undergoing general anaesthesia since anaesthesia can interfere with renal function. The risk of lactic acidosis associated with metformin increases in patients with renal impairment. Metformin should be stopped before and during surgery where anaesthesia is indicated. Metformin should only be restarted after the renal function has returned to normal. 

Renal impairment - Metformin is contraindicated in patients with renal impairment. Therefore, concomitant administration of rosiglitazone and metformin is contraindicated in these patients. However, no dosage adjustment is necessary when rosiglitazone is used as monotherapy in patients with renal impairment. 

Renal function impairment Metformin is known to be excreted by the kidney, and the risk of metformin accumulation and lactic acidosis increases with the degree of impairment of renal function. Do not give metformin to patients with serum creatinine levels above the upper limit of normal for their age. 

Biguanides 1-2.0% Metformin 500-1700 Avoid with renal impairment, CHF... 

Of 308 patients 73% had contraindications, risk factors, or intercurrent illnesses necessitating withdrawal of metformin (31) 19% had renal impairment, 25% heart failure, 6.5% respiratory insufficiency, and 1.3% hepatic impairment 51% had advanced coronary heart disease, 9.8% atrial fibrillation, 3.3% chronic alcohol abuse, 2% advanced peripheral arterial disease, and 0.7% were pregnant. 

In a retrospective study of 1874 patients with type 2 diabetes taking metformin, 25% had contraindications, including acute myocardial infarction, cardiac failure, renal impairment, and chronic liver disease (33). However, contraindications often did not lead to withdrawal of metformin in 621 episodes, only 10% stopped taking it. Only 25 and 18% stopped taking metformin when they developed renal impairment or myocardial infarction, respectively. One patient developed lactic acidosis, but this may have been a consequence of myocardial infarction. 

Experience with metformin in a large American health organization in 9875 patients has been presented (68). There was one probable case of lactic acidosis in an 82-year-old woman who developed renal impairment while taking metformin 500 mg/day. 

A 64-year-old man, who used, amongst other drugs, glibenclamide 2.5 mg/day and metformin 850 mg bd, lost consciousness after a week of dwindling appetite and loose stools. His blood glucose was 2.2 mmol/1. He had renal impairment (creatinine 362 pmol/1). He also used ranitidine and ramipril 2.5 mg/day, which could have contributed to both the hypoglycemic effect and renal insufficiency. 

The clearance of lactate may be reduced in liver impairment, leading to the possibility of accumulation and increased potential for lactic acidosis. Concurrent renal impairment with liver impairment could further increase the risk with drugs known to cause lactic acidosis, e.g. metformin and nucleoside reverse transcriptase inhibitors [2]. 

METFORMIN NS AIDS Possibility oft plasma levels of metformin if there is renal impairment due to NSAIDs. Phenylbutazone is likely to i renal elimination of metformin and t plasma levels. 

Metformin (t) 5 h) is taken with or after meals. Its chief use is in the obese patient with Type 2 diabetes either alone or in combination with a sulphonylurea. It has a mild anorexic effect which helps to reduce weight in the obese. The action of metformin is terminated by excretion by the kidney and it should not be used in the presence of renal impairment. 

Lactic acidosis can occur after the use of intravascular iodinated contrast agents in patients taking metformin. Metformin is excreted by the kidneys, and renal insufficiency can lead to its retention, which can cause fatal lactic acidosis. The manufacturers have recommended that metformin should be withdrawn for 48 hours before and 48 hours after the administration of intravascular contrast media, which can cause renal damage, and treatment should not be restarted until normal renal function is confirmed. Reviews of reported cases of lactic acidosis after contrast administration have shown that there was pre-existing renal impairment in all cases. A retrospective evaluation of patients taking metformin who underwent... 

Iodine contrast agents interact with metformin, an oral hypoglycaemic drug used to treat type 2 diabetes (see Chapter 6). Iodine contrast agents increase the risk of a patient developing lactic acidosis with metformin, particularly if their kidney function is impaired. Metformin has to be stopped prior to radiological examination and should not be restarted until normal renal function has resumed. 

Patients with renal impairment should not receive metformin. Other contraindications include hepatic disease, a past history of lactic acidosis, cardiac failure requiring pharmacological therapy, or chronic hypoxic lung disease. The drug also should be discontinued temporarily prior to the administration of intravenous contrast media and prior to any surgical procedure. The drug should not be readministered any sooner than 48 hours after such procedures, and should be withheld until renal function is determined to be normal. These conditions all predispose to increased lactate production and hence to the potentially fatal complication of lactic acidosis. The reported incidence of lactic acidosis during metformin treatment is less than 0.1 cases per 1000 patient-years, and the mortality risk is even lower. 

Parenteral administration of iodinated contrast media to patients taking metformin may result in lactic acidosis. However, the problem is reported to occur only if the contrast media causes renal failure and metformin use is continued. This is because metformin is mainly excreted by the kidneys and in renal failure toxic levels may accumulate, which may result in lactic acidosis. A literature search identified 18 cases of lactic acidosis after the use of contrast media in patients taking metformin. Of these 18 cases, 14 or 15 were associated with pre-existing renal impairment and 2 cases with other contraindications to metformin (sepsis and cirrhosis). The remaining case was in an elderly woman with neurological disease. 

A 64-year-old woman with mild chronic renal impairment who was taking metformin 3 g/day, allopurinol 300 mg/day, verapamil 120 m day, irbesartan 300 m day, and forosemide 25 mg/ day, developed nausea, vomiting, and abdominal pain 6 days after a surgical procedure [38 ]. The serum creatinine concentration had risen to 500 j,mol/l, and the pH was 7.16 with a serum bicarbonate of 11 mmol/1. She was treated with sustained low-efficiency daily dialysis (SLEDD) with GENIUS . Acid-base balance returned to normal after three treatments. 

Under certain circumstances, and very rarely, the inhibition of gluconeogenesis by metformin may suppress lactic acid metabolism and precipitate a potentially fatal lactic acidosis. Impairment of renal function, liver disease, alcoholism, conditions that give rise to increased lactate production (e.g. congestive heart failure, infections) are therefore contraindications for the application of metformin. 

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