In this Article:
01: Biguanides 02: Sulphonylureas03: Alpha-glucosidase inhibitors04: Prandial glucose regulators 05: Thiazolidinediones06: GLP-1 agonists07: DPP-4 inhibitors08: SGLT-2 inhibitors09: Insulin10:
Biguanides
Biguanides are a class of drugs used to treat type 2 diabetes by lowering the levels of glucose (sugar) in the blood. In the UK, the only biguanide medication available on the NHS is metformin, and it’s one of the most commonly used medicines to treat type 2 diabetes, sometimes with other medications including insulin.
Metformin helps your body respond as it should to insulin, which means it may initially cause an upset stomach and/or diarrhoea. However, it’s an effective medicine for type 2 diabetes, and symptoms should diminish over time if you take it with food and increase the dose slowly as advised by your doctor.
Sulphonylureas
Sulphonylureas stimulate the pancreas to increase insulin secretion, which helps lower blood sugar levels in your body. They’re a well-established treatment for type 2 diabetes in the UK, prescribed as glimepiride and gliclazide. They’re helpful for people who have type 2 diabetes due to genetic factors or steroid medication.
Sulphonylureas are prone to causing hypoglycaemia, particularly if you take too high a dose or skip a meal, so it’s a good idea to monitor your blood glucose levels at home. Like metformin, sulphonylureas can also cause stomach upset, and you should also check with your doctor about taking them and driving as they can affect concentration.
Alpha-glucosidase inhibitors
There is only one alpha-glucosidase inhibitor licensed to treat type 2 diabetes in the UK – acarbose*. It is usually prescribed when a healthy diet and exercise have not sufficiently lowered your blood sugar levels. It works by slowing down the body’s absorption of starch and sugar, and can often be taken alongside other medications, like sulphonylureas.
Common side effects include stomach upset, but the risk can be reduced. You should try to take your medication at the start of a meal and chew it together with food or just before you eat with a small amount of liquid.
*has poorer glucose-lowering efficacy and is considered only if other oral agents aren’t tolerated.
Prandial glucose regulators
Prandial glucose regulators help your pancreas to increase insulin production. Also known as glinides, meglitinides, or meal-time glucose regulators, you can take them on their own, as a metformin replacement, or use them with metformin if you’re blood sugar levels aren’t reaching their target range.
They are similar to sulphonylureas and have many of the same side effects, including stomach upset, diarrhoea, and potential hypoglycaemia. They work very quickly but only last for a short time. You should take them up to 30 minutes before each meal and take care when driving, exercising, or drinking alcohol.
Thiazolidinediones
Thiazolidinediones, sometimes known as glitazones, treat type 2 diabetes by helping your body respond better to the insulin created by your pancreas. This helps to regulate, or lower, the amount of sugar in your blood. There is only one medication in this class of drugs, called pioglitazone.
Pioglitazone is often prescribed if metformin isn’t suitable for you, but it can also be taken together with other diabetes medications, including metformin or a sulphonylurea. Side effects include weight gain, so it’s important you maintain a healthy diet and regular exercise when you take it.
GLP-1 agonists
GLP-1 agonists are either once-weekly injections or daily oral tablets used to treat type 2 diabetes. They work by increasing the levels of hormones called incretins, which help the body produce more insulin when needed and reduce the amount of glucose the liver produces when it’s not required. They also help lower the rate at which the stomach empties and digests food.
You can take them on their own or with other diabetes medication, but they are commonly used to support clinical weight loss (GLP-1 medicines for diabetes are licensed differently to GLP-1 medicines for weight loss and are prescribed under different brand names, like Ozempic or Wegovy), whether you have type 2 diabetes or not. Common side effects include stomach upset and diarrhoea, so it’s important that you start on a low dose and gradually increase it to help with this.
DPP-4 inhibitors
Also known as gliptins, DPP-4 inhibitors treat type 2 diabetes by blocking the action of the DPP-4 enzyme, which destroys hormones that help to regulate insulin levels and blood sugar. The hormones, known as incretins, are naturally produced by the stomach when we eat. They help the body make insulin when it’s needed and reduce glucose levels when it’s not needed.
You can take DPP-4 inhibitors with or without food, but common side effects include headaches and diarrhoea. You can try taking them with food and staying hydrated to help with this. They are often prescribed as an alternative if metformin isn’t suitable for you, or with other diabetes medications if your blood sugar levels aren’t in target range.
SGLT-2 inhibitors
Also known as gliflozins, SGLT-2 inhibitors help to treat type 2 diabetes by removing excess glucose (sugar) through the kidneys via urine. Due to this, they can increase the frequency of urination and increase the chances of cystitis or thrush, so it’s important you stay hydrated on this medication.
They can also be used in certain patients with kidney disease for kidney protection.
SGLT-2 inhibitors are prescribed if metformin isn’t suitable for you, and you have developed chronic heart failure or heart disease, but they can also be used with other diabetes medication. You should take them in the morning, so you don’t have to get up to go to the toilet too often during the night.
Insulin
Insulin is given to everyone with type 1 diabetes, but it can also be given to some people with type 2 diabetes. It works for the latter by allowing blood sugar to move into the body's cells and be used, lowering the amount in the blood. It can help prevent short and long-term health problems and complications.
It comes either in injection or continuous infusion pump form. There are different types of insulin, short-acting or long-acting. Which one you are prescribed depends on your medical history, and you’ll be given a tailored plan.
