Thiazolidinediones are a type of medication you might need to take if you have type 2 diabetes. They are also referred to as glitazones.
- What are thiazolidinediones?
- How do thiazolidinediones work?
- How to take thiazolidinediones
- Who can take thiazolidinediones?
- Your prescription
- Side effects of thiazolidinediones
- More information and support
What are thiazolidinediones?
Thiazolidinediones are a treatment for managing blood sugar levels. There is one tablet in this drug class called pioglitazone, which has the brand name Actos.
It can also be taken as a tablet which contains pioglitazone and metformin which is sometimes prescribed as the brand name Competact.
How do thiazolidinediones work?
Thiazolidinediones help cells in your body respond better to the insulin your pancreas makes. This helps to lower blood sugar levels.
How to take thiazolidinediones
Pioglitazone is a tablet that you swallow, which comes in different strengths. You can take it with or without food. It should be taken with a drink of water and swallowed whole.
If you take the tablet that also has metformin in it, you should take this with food.
Always take thiazolidinediones exactly as your healthcare professional has told you. The Patient Information Leaflet inside the box will tell you how to take it but always check with a doctor or pharmacist if you are not sure.
Who can take thiazolidinediones?
Adults over the age of 18 years with type 2 diabetes can take thiazolidinediones.
You can take pioglitazone on its own or with other diabetes medications such as metformin, sulphonylureas or insulin.
Who can’t take thiazolidinediones?
Some medications might not be suitable for some people, which might be because of medical conditions or other reasons:
- Your healthcare team will tell you to stop taking pioglitazone if you develop diabetic ketoacidosis, or DKA;
- Pioglitazone might not be suitable for you if you have heart failure, bladder cancer or blood in your urine. You may also need to temporarily stop taking it if you're going to have an operation;
- If you have kidney disease you might not be able to take pioglitazone, but this will depend on the stage of your kidney disease;
- If you have liver disease you might not be able to have pioglitazone;
- You should not use thiazolidinediones if you are pregnant of breastfeeding. If you’re planning a pregnancy speak with a healthcare professional if you are using this medication.
You might need to temporarily stop taking a thiazolidinediones if you’re going to have an operation.
When you start a new medication always check with your healthcare team that it’s suitable for you to take.
Your prescription
Your healthcare team should explain your prescription to you but it's important to make sure you ask if you don't feel you know enough.
And make sure you talk to your GP or your diabetes team if you struggle to take your medication. They might be able to help by giving you a different dose.
In England, if you need to take any medication to manage your diabetes, your prescriptions will be free. Ask your healthcare team about a prescription exemption certificate if you don't have one, to make sure you don't get charged for your medication. Prescriptions are already free for everybody in the rest of the UK, so you shouldn't pay for your medication.
Side effects of thiazolidinediones
Like all medications, thiazolidinediones can cause side effects. But when side effects are listed as common in the Patient Information Leaflet, it doesn’t mean that everyone that takes the medication will get them.
The information about side effects is based on the likelihood of people having them. For example, if a side effect is very common then it can affect more than one in ten people, and if a side effect is very rare then it affects fewer than one in 10,000 people.
Because medicines can affect people differently, your healthcare team will speak to you about what’s best for you and discuss any side effects. Side effects can include:
- Increased risks of infections in the throat or lungs;
- Some people find that they gain weight while taking pioglitazone. Eating a healthy balanced diet and physical activity can help you to manage weight gain;
- A serious side effect that can happen is that you can be at a higher risk of breaking a bone;
- A common side effect if you take pioglitazone with insulin is swelling in parts of your body, such as the legs. This is called oedema. Speak to your healthcare team if you develop swelling;
- There is a small increased risk of bladder cancer if you take pioglitazone. You should not take pioglitazone if you have active bladder cancer, a history of bladder cancer or if you are being treated because of blood in your urine.
Risk of low blood sugar
Pioglitazone does not usually cause blood sugar levels to become too low, also known as hypoglycaemia or hypos, when taken on its own. However, hypos can happen when you take pioglitazone with other diabetes medications such as insulin or a sulphonylurea.
Your healthcare team may advise reducing the dose of your sulphonylurea or insulin medicine when you start taking pioglitazone to reduce the risk of hypos.
These are not all the side effects. You will find a full list of known side effects in the Patient Information Leaflet. This comes in the medication box.
It’s also important that you take individual advice from your healthcare team before starting pioglitazone treatment and report any side effects to your healthcare professionals, if you have any.
You can also report these side effects to the Yellow Card Scheme, which is the government system used for recording side effects with medicines in the UK.
More information and support
Still have more questions? Or is there anything you're not sure about thiazolidinediones after reading this page? Contact our helpline on 0345 123 2399.
You can visit the NHS website for more information on thiazolidinediones.
