Does Metformin, a glucose-lowering drug, hurt the kidneys?

 Metformin is a biguanide compound that reduces blood sugar mainly by reducing hepatic glucose output, improving insulin resistance, and reducing glucose absorption in the small intestine. It is currently one of the world's most widely used oral hypoglycemic drugs. Drug safety evaluation studies have found that Metformin has a good safety profile, no carcinogenic or mutagenic effects, and no evidence that Metformin can increase the risk of lactic acidosis. Medicilon has a professional team and experience in preclinical drug safety evaluation services, providing high-quality data and a fast turnaround time to support all drug safety evaluation studies.

Many patients are concerned about the effects of long-term metformin use on the kidneys. The drug does not directly damage the kidneys but can lead to drug accumulation when taken by patients with existing kidney damage. Both the Chinese Guidelines for the Prevention and Treatment of Type 2 Diabetes (2017 edition) and the Expert Consensus on the Clinical Application of Metformin (2016 edition) suggest that Metformin is the drug of choice for the treatment of type 2 diabetes in the absence of contraindications and intolerance, and should always be retained in the glucose-lowering regimen.

One 、Benefits of Metformin.

Metformin can reduce hyperglycemia with no hypoglycemic effect on those with regular blood sugar; the drug has the following benefits in addition to hypoglycemia.

(1), Metformin has the effect of reducing body weight.

(2) Metformin has apparent cardioprotective effects and reduces the risk of cardiovascular disease in newly diagnosed and established type 2, diabetes patients.

(3) Metformin can improve lipid synthesis, metabolism, and lipid profile.

(4) Metformin significantly improved liver serological enzyme profile and metabolic abnormalities in patients with non-alcoholic fatty liver.

Two 、Adverse reactions and countermeasures

The main adverse reactions of Metformin are diarrhea, nausea, vomiting, gastric distension, and other gastrointestinal responses, which mainly occur in the early stage of treatment (the majority happen in the first ten weeks). Most patients can gradually tolerate them, or their symptoms disappear as the duration of treatment increases. Start taking small doses, gradually increase the amount, adjust the quantity at the right time, take with meals, and choose enteric preparations and other methods, which can reduce gastrointestinal reactions.

Three 、Does Metformin hurt the liver and kidney?

Metformin has no hepatic and renal toxicity; Metformin is absorbed through the gastrointestinal tract for blood circulation, almost does not combine with plasma albumin, does not go through liver metabolism, does not compete with liver P450 enzymes, and does not degrade in the body, but acts directly on the liver and muscle, reducing hepatic glucose isomerism and increasing muscle glucose enzymes. Therefore, Metformin is not hepatotoxic.

Metformin is mainly excreted from the urine in its original form by the kidneys and is cleared rapidly, with approximately 90% clearance in 12-24h. The renal clearance of Metformin is about 3.5 times higher than that of creatinine, and renal tubular excretion is the main route of metformin clearance. Therefore, Metformin itself is not harmful to the kidney.

However, caution should be exercised when using Metformin in people with impaired liver and kidney function. Metformin should be avoided when serum transaminases exceed three times the upper limit of normal, and patients with renal insufficiency need to adjust the dose by estimating the level of glomerular filtration rate. Clinicians or pharmacists can assess the above.

Four、 Long-term use of Metformin, the need for appropriate supplementation of vitamin B12

Studies have shown that: the incidence of vitamin B12 deficiency in glucose patients using Metformin is 5.8%, while the incidence of vitamin B12 deficiency in glucose patients not using Metformin and people without diabetes is 2.4% and 3.3%, respectively. Therefore, long-term metformin users should monitor vitamin B12 concentration regularly and increase the intake of vitamin B12-rich foods appropriately (vitamin B12 is mainly contained in animal proteins, such as meat, animal liver, fish, shellfish, eggs, etc.) to prevent and correct vitamin B12 deficiency. If this condition occurs, vitamin B12 should be supplemented in an appropriate amount under the guidance of professional doctors.

Five 、Stop taking Metformin 48 hours before and after doing a CT examination

Diabetic patients should stop taking Metformin 48 hours before and after doing enhanced CT because it is necessary to play contrast agent before doing CT. The contrast agent belongs to macromolecular substances excreted through the kidneys. If you retake Metformin, it will increase the burden on the kidney and cause contrast nephropathy.

Six、 The icing on the cake: combined with other glucose-lowering drugs

There are several different drugs when taking glucose-lowering drugs, often more than Metformin. This is because the combination of glucose-lowering medications mutually increases the hypoglycemic effect, improves insulin resistance, or reduces adverse reactions.

All diabetic patients should choose the appropriate hypoglycemic drugs according to their different conditions and pay attention to the indications and contraindications of each type of drug. At the same time, it is essential to emphasize that diet therapy and diet control are the cure for diabetic patients and must be adhered to for life. Diet therapy should not be relaxed or abandoned because of oral hypoglycemic drugs or increased dosages of hypoglycemic medications.