We found no significant association between metformin use and risk of other neoplasms such as prostate, breast, kidney, melanoma, uterus, ovarian, lung, and bladder cancer.
The meta-analysis showed that therapy with metformin use was associated with decreased risk for all cancer. Furthermore, except for colorectal cancer, metformin was not associated with any significant effect on the incidence of other cancers, for example, prostate and breast cancers.
Overall, the risk of developing cancer from NDMA exposure is very low. However, if you are taking metformin and are concerned about this risk, you should discuss your concerns with your healthcare team. Don't stop taking metformin until you've discussed it with your physician or another member of your healthcare team.
The safety profile for metformin is quite good. Side effects include nausea, stomach upset, or diarrhea; these tend to be mild. More serious side effects are rare. They include severe allergic reactions and a condition called lactic acidosis, a buildup of lactic acid in the bloodstream.
For example, metformin has been shown to inhibit AKT/mTOR signalling and suppress fatty acid synthesis in an AMPK-dependent manner [8,9,10]. Metformin-induced AMPK activation has also been shown to reduce cancer cell proliferation through several other mechanisms, including activation of cMYC, HIF-1α and DICER1 [11].
For example, several studies have shown metformin use to lower insulin levels in the blood for the treatment of breast cancer in women. Studies have also shown that there is an increased risk of various cancers, including colon, breast, pancreas and uterus cancers in diabetic and obese patients.
Metformin doesn't cause kidney damage. The kidneys process and clear the medication out of your system through your urine. If your kidneys don't function properly, there's concern that metformin can build up in your system and cause a condition called lactic acidosis.
Metformin may have an adverse effect on renal function in patients with type 2 DM and moderate CKD.
How long to take it for. Treatment for diabetes is usually for life. But if your kidneys are not working properly, your doctor will tell you to stop taking metformin and switch you to a different medicine. Do not stop taking metformin without talking to your doctor.
Under certain conditions, too much metformin can cause lactic acidosis. The symptoms of lactic acidosis are severe and quick to appear, and usually occur when other health problems not related to the medicine are present and are very severe, such as a heart attack or kidney failure.
Ruiter et al reported that exposure to metformin was generally associated with lower incidence of cancer, specifically gastric cancer, when compared to exposure to sulfonylurea derivatives.
Metformin was inversely associated with liver cancer (adjusted hazard ratio [aHR] = 0.44, 95% CI 0.31, 0.64) compared to sulfonylurea.
Metformin may rarely cause a serious, life-threatening condition called lactic acidosis. Tell your doctor if you have kidney disease. Your doctor will probably tell you not to take metformin.
A meta-analysis of seven randomized trials involving metformin as a treatment for type 2 diabetes that reported data on cancer adverse events found no association between metformin treatment and the risk of developing any malignancy (odds ratio [OR] 0.98; 95% CI 0.81–1.19), although cancer was not a prespecified end ...
Metformin may also exhibit anti-cancer activity by reducing circulating glucose and insulin levels. Metformin, an insulin sensitizer, decreases plasma insulin and insulin-binding proteins, which can reduce insulin growth factor-1 (IGF-1) levels.
Metformin can also inhibit tumor growth through the mTOR signaling in AMPK-dependent and -independent pathway (56). Treatment with metformin lowers serum levels of insulin and insulin-like growth factor-1 (IGF-1), which are both potential growth factors capable of stimulating cell survival and mitogenesis (57, 58).
If you stop taking metformin abruptly, your health may suffer. You may experience side effects such as higher blood sugars, an increased A1c, and even weight gain. Over time, higher blood sugar levels can lead to diabetes complications, including: Retinopathy and blindness.
Standard metformin is taken two or three times per day. Be sure to take it with meals to reduce the stomach and bowel side effects that can occur – most people take metformin with breakfast and dinner. Extended-release metformin is taken once a day and should be taken at night, with dinner.
But if you can't tolerate metformin or it's not doing enough to help you reach your diabetes goals, you may need an alternative. If you also have heart or kidney disease, GLP-1 agonists like Ozempic (semaglutide) or SGLT2 inhibitors like Jardiance (empagliflozin) are good alternatives.
HOMA-IR, an indicator of insulin resistance, was also significantly decreased by metformin and cinnamon intake. Moreover, no difference was seen in the ability of cinnamon and metformin in reducing HOMA-IR. As a result, cinnamon seems to be as effective as metformin in increasing the Insulin sensitivity.
Mechanism of Injury
Metformin may actually be beneficial for some forms of liver disease, such as nonalcoholic steatohepatitis and need not be avoided in patients with mild, preexisting serum enzyme abnormalities. Acute liver injury from metformin may have a metabolic basis, arising after weeks to months of therapy.