Diarrhoea is the most common side effect of metformin. Here are things you need to know before starting metformin for type 2 diabetes

It is well known that metformin can cause diarrhoea and this is one of the most common side effect that people experience (The Prevalence of Chronic Diarrhea Among Diabetic Patients). It should ‘settle’ after starting on the medication. But what if it doesn’t? What does ‘settle’ actually mean and how do you know if you should continue taking it? Also, why should you actually take something which causes such symptoms?

One of the ways that metformin works is directly on the gut and this can lead to symptoms of nausea and diarrhoea, especially in the first few of weeks taking it. That’s why you should start on a low dose to get used to it and also why most preparations are now slow-release. Only about 5% of those taking it actually have to stop long term due to this side effect as in the majority of people it either resolves or is ‘manageable’.

Looking through search engines such as google and websites you will find that there is little information relating to how long it takes for diarrhoea to settle. In fact, the truth is that most people have a different view of what diarrhoea actually is and if they can tolerate it. Loose stool may mean 3 or 4 times a day or less (or more) and not be an issue. Liquid, explosive episodes with little warning on the other hand can definitely impact daily life and lead to other health problems and dehydration. Some people prone to constipation may actually not mind being a little loose!

The important thing is to recognize when it is a problem, and, if it could the sign of something else such as infection or even cancer. One way to find out if it is the metformin is to stop taking it for a few days. After 3 or 4 days if you still have diarrhoea then you have your answer. If you have not ever had a problem and suddenly are aware that your bowel habits have changed then it could indicate a serious problem and you definitely need to get that checked out with your doctor.

So, I guess by now you are wondering
why on earth you should take Metformin at all…

It is actually a really good medication that works not only to help regulate blood glucose levels but also decreases the amount of insulin you need. Slowing the actual progression of diabetes, it has also been linked to other health benefits such as reducing cardiovascular events such as heart attacks and strokes; lowering cholesterol levels and even protecting against cancers. For more information please refer to Benefits of Metformin. Studies indicate that it should be the drug of first choice on diagnosis of type 2 diabetes for very good reasons (American Diabetes Association: Approaches to Glycemic Treatment). It is also used in pre- diabetes, gestational diabetes and polycystic ovarian syndrome and is considered a safe medication to take with few side effects other than those affecting the gut.

It is important therefore to first weigh up the pros and cons of taking metformin and talk to your doctor before stopping it to ensure you are making the best choice for your diabetes and general health. It may be as simple as a reduction in dose or changing brands to make a real difference.

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