What to Know About Metformin

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What to Know About Metformin

You may need to stop taking metformin before having a test that uses contrast dye.

If you take metformin and are due to have a CT scan, MRI or angiogram that involves the use of IV contrast dye, talk with your doctor about stopping your metformin before the procedure. The contrast dye may cause minor, short-term changes to your kidney function. According to the American College of Radiology, you may not need to stop your metformin if you have normal kidney function. However, if you have acute or chronic kidney issues, you will likely need to stop taking your metformin prior to the procedure, and 48 hours afterwards. Make sure you let all of your doctors know which medicines you take, and be sure to ask about taking metformin if you will be having any procedure that involves use of a contrast dye.

Metformin may help with weight loss.

Metformin isn’t a weight-loss drug. But studies show that some people who take this medicine lose weight — as long as they are eating healthfully and being active. How does metformin work to cause weight loss? Researchers aren’t entirely clear, but weight loss may result from a reduced appetite. Metformin may also affect how the body stores fat. And metformin lowers insulin resistance, which can make it easier to lose weight. On a side note, metformin is sometimes prescribed to people who take antipsychotic medicines to prevent or reduce weight gain. Keep in mind that metformin is not a magic diet pill, and if you take it, you may not notice any effect on your weight.

Metformin may help prevent some types of cancer.

Metformin has shown some promise in improving survival in breast cancer patients and those with endometrial hyperplasia, a condition that can lead to cancer if not treated. According to the National Cancer Institute, numerous trials are underway to find out if metformin can prevent a number of different cancers, including breast, prostate, colorectal and endometrial cancers. Stay tuned!

Metformin helps to reduce heart disease deaths in those with type 2 diabetes.

One of the main complications of diabetes is heart disease. Research on more than one million people with diabetes shows that metformin can reduce the risk of dying from heart disease by 30% to 40%, compared with sulfonylurea drugs (another class of diabetes pills). Results from a newer study, called REMOVAL, showed that metformin lowered LDL cholesterol, plaque accumulation and weight in more than 400 people with type 1 diabetes, indicating that this drug may be helpful for preventing heart disease in those with type 1 diabetes.


Metformin sometimes smells like a dead fish.

The smell of a dead fish is one of the worst smells around. Understandably, if your medicine smells like this, it’s going to be hard to swallow. And many people find that fishy metformin increases the chances of nausea. What gives with the fishy smell? Apparently, generic metformin has a higher likelihood of smelling bad. If you notice a bad smell when you open your metformin container, you can try a couple of things: hold your nose when you take it, or talk to your doctor about switching to another type of metformin, including an extended-release version.

There are definitely pros and cons to taking metformin. Talk with your doctor or diabetes educator if you have concerns or questions about this drug, and find out if it’s a good choice for you.

Want to learn more about metformin? Read “Diabetes Medicine: Metformin” and “Metformin: The Unauthorized Biography.”

Originally Published October 2, 2017


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