Metformin

PATIENT INFORMATION SHEET 

Cancer cells function differently from normal cells because they are much more reliant on the sugars (glucose), fats and cholesterol in the blood in order to reproduce.  Scientific data suggests that the growth of the cancer can be influenced by lowering glucose fat and cholesterol.  

METFORMIN (Glucophage) This information is about a type of anti-diabetic medicine known as a biguanide called Metformin. Metformin works in a number of ways to decrease the amount of sugar in the blood for people suffering with type two diabetes, who are often, called non-insulin dependent diabetics. Scientific data suggests this medication can be additionally used for an extensive range of disorders and diseases, including cancer.  

INSULIN Type two diabetic patients produce insulin, however either the amount the pancreas produces is insufficient, or their body is unable to use it appropriately. Insulin is the main hormone responsible for the levels of sugar in the blood. When the insulin supply is low or not been used correctly the glucose cannot get into the cells and they are unable to function properly.  

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WHAT IS METFORMIN? 

Metformin is a drug which is used for patients will type two diabetes. The medicine reduces the amount of sugar made by the liver, limits the amount of sugar absorbed into the body from the diet, and makes insulin receptors more sensitive (helping the body respond better to its own insulin). All of these effects cause a decrease in blood sugar levels. Metformin additionally elevates the receptors (GLUT4) which take glucose into the healthy cells, which lowers the circulating blood sugar levels. 

Metformin may additionally be useful for patients with cancer because the cancer cells become ‘sugar hungry’. Energy for the cancer can come from the processing of glucose metabolites and in order for the cancer to achieve its requirements the cells create more receptors (GLUT1) to bring in the glucose. Metformin reduces the cancers energy supply by reducing the amount of sugar produced. Metformin still allows glucose into normal cells with ours through a different sort of receptor.    WHEN IS IT GIVEN? Your doctors will discuss the dosages and length of treatment appropriate for you. You will start on a low dose which will be titrated under your oncologist’s supervision following regular checks in the clinic in order to achieve a suitable dose Metformin can be given as a lifelong treatment. 

SIDE EFFECTS 

Below is an outline of the most common side effects, a full list including those that are rare is provided with the drugs each time they are supplied in the package Insert leaflet.  Your doctor may prescribe concurrent medications to counteract your side effects if required. 

Abdominal or stomach discomfort 

Cough or hoarseness 

Decreased appetite 

Diarrhoea 

Fast or shallow breathing 

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Fever or chills 

General feeling of discomfort 

Lower back or side pain 

Muscle pain or cramping 

Painful or difficult urination 

THINGS TO REMEMBER 

 If you miss a dose of this medicine, take it as soon as possible. However, if it is almost time for your next dose, skip the missed dose and go back to your regular dosing schedule. Do not double dose. 

 Alcohol— drinking alcohol may cause severe low blood sugar. Discuss this with your health care team.

 Metformin does not exert a hypoglycaemic action in non-diabetic subjects unless given in overdose. 

 Do not take metformin on the morning of surgery or planned procedures involving anaesthesia.  

 Do not take metformin on the day of any scan with contrast and for 48 hours after the scan. The contrast material may affect how your kidneys clear metformin from your body. (new guidelines mean that some NHS hospitals no longer require patients who take Metformin to stop their medication, but this can vary between hospitals and we would rather err on the side of caution on this point) 

REFERENCES 

British Medical Association and the Royal Pharmaceutical Society of Great Britain (2013) British National Formulary, BMJ Publishing Group, 66th Edition, pp 454-455. 

Version 1.0 (Created December 2013) 

Gallagher. E and LeRoith. D (2011) Diabetes, cancer, and metformin: connections of metabolism and cell proliferation, Annals of the New York Academy and Sciences, pp 64-68. 

Yin. M, Zhou. J, Gorak. E and Quddus. F (2013) A Systematic Review and Meta-Analysis Metformin Is Associated With Survival Benefit in Cancer Patients with Concurrent Type 2 Diabetes, The Oncologist, 18(11).