Medicines for diabetes

Metformin makes your body more sensitive to insulin. This makes the insulin better at allowing glucose to be taken up by your cells. This can be the insulin made by your pancreas, or the insulin taken by injection or insulin pump.

Your liver also releases less glucose into your blood when you take metformin.

The most common side effects of metformin mainly affect the gastrointestinal system (your tummy and gut), and include diarrhoea, nausea, vomiting, and cramps/bloating.

Sulfonylureas tell the pancreas to make more insulin. This means more glucose can be taken up by your cells. Examples of sulfonylureas include gliclazide, glimepiride, glibenclamide and glipizide.

Because sulfonylureas increase the amount of insulin in your body, hypoglycaemia (low blood glucose) is a possible side effect. You may need to regularly check your blood glucose levels. Other side effects may include weight gain, skin rashes and diarrhoea.

DPP-4 inhibitors signal the pancreas to release more insulin after you eat, which helps your cells take up more glucose from your blood. Your liver also releases less glucose into your blood when you take a DPP-4 inhibitor. Examples of DPP-4 inhibitors include alogliptin, linagliptin, saxagliptin, sitagliptin and vildagliptin.

The most common side effects include nausea and headaches, and they may also increase your chance of catching a cold. These medicines rarely cause low blood glucose levels unless combined with sulfonylureas or insulin.

SGLT2 inhibitors help lower blood glucose levels by removing extra glucose from your body through your urine. SGLT2 inhibitors also help protect your heart and kidney health. Examples of SGLT2 inhibitors include dapagliflozin and empagliflozin.

Possible side effects can include urinary tract infections (UTIs), genital thrush, needing to urinate (wee) more often, and dehydration. Diabetic ketoacidosis (DKA) is a rare but serious side effect.

GLP-1 receptor agonists are taken by once-weekly injection, but they are not a type of insulin. They mimic a hormone your body makes called GLP-1, which tells the pancreas to make more insulin after you eat, and reduces the amount of glucose released by your liver. GLP-1 receptor agonists also slow down the digestion of food and reduce appetite, so they may help you lose weight if you are overweight. Examples of GLP-1 receptor antagonists include semaglutide and dulaglutide.

Nausea, headaches, dizziness, vomiting, diarrhoea, and constipation are possible side effects. A rare but serious side effect is pancreatitis.

Alpha glucosidase inhibitors (acarbose) slow down how fast the carbohydrate you eat is broken down into glucose.

The most common side effects include flatulence (wind), tummy rumbling, and other tummy upsets such as diarrhoea, nausea, indigestion, and vomiting.

Glitazones make your body more sensitive to insulin, which means insulin becomes better at allowing glucose to be taken up by your cells. Examples are pioglitazone and rosiglitazone.

Possible side effects include a small increase in weight, signs of hypoglycaemia (low blood glucose), and eye problems such as blurred or double vision. Less common but more serious side effects include impaired liver function, heart failure, and higher risk of fractures (especially in women).