Common questions about rapid-acting insulin - Brand names: Admelog, Apidra, Fiasp, Humalog, Lyumjev, NovoRapid, Trurapi

Insulin is a hormone made in your pancreas (a gland behind the stomach). When food is digested and enters your bloodstream, insulin moves glucose out of your blood and into cells, where it's broken down to produce energy.

When your pancreas is working properly, it's constantly making small amounts of insulin and releases more insulin when your blood glucose levels rise after eating.

When you have diabetes, your body does not make enough insulin or the insulin that it makes does not work properly. You need to inject insulin to replace what your body cannot produce.

There are several different types of insulin. Rapid-acting insulin works very quickly and you take it shortly before meals.

Unless you use an insulin pump, you'll usually also need a separate long-acting insulin or intermediate-acting insulin once or twice a day, to give you a continuous low level of insulin in your body when you're not eating.

Rapid-acting insulins are all types of human insulin. This is the name given to insulin grown in the laboratory that is a copy of the insulin made by the human pancreas.

Rapid-acting insulins are also known as rapid-acting recombinant human insulin analogues. This means they are chemically very similar to human insulin but the structure of the insulin molecule has been changed slightly to improve how well it works in the body.

Rapid-acting insulin starts to work in around 15 to 20 minutes and its effects last for up to 5 hours.

You generally need to take it around 15 minutes before meals so that your levels of insulin are highest when your body is absorbing glucose from food and your blood glucose levels are highest. But check this with your diabetes specialist because each brand of rapid-acting insulin is slightly different.

If you use rapid-acting insulin in an insulin pump, the pump is programmed to automatically deliver small amounts of insulin into your body all the time. You'll also need to use the pump controls to deliver an extra dose (sometimes called a bolus dose) up to 20 minutes before eating.

You can see images showing how long each type of insulin lasts on the NHS My Type 1 Diabetes website.

The insulins used to treat diabetes are very similar to the insulin produced naturally in the body. Insulins have been used to treat diabetes for over 100 years.

You should not have any long-term side effects as long as you use the right injection technique.

There are 3 different types of rapid-acting insulin:

• insulin aspart (Fiasp, NovoRapid and Trurapi)
• insulin lispro (Admelog, Humalog and Lyumjev)
• insulin glulisine (Apidra)

They are very similar in how they affect your blood sugar, but they need to be taken using different types of insulin pen or pumps.

Most brands of rapid-acting insulin contain 100 units of insulin per 1ml, but there are also 2 brands of insulin lispro (Humalog and Lyumjev) that contain 200 units of insulin per 1ml. This means that you need to inject half as much liquid to get the same number of units of insulin because the insulin is double concentrated. They are usually only prescribed for people who need high doses of insulin to manage their blood sugar.

Rapid-acting insulin works quickly and you take it before meals, to stop your blood glucose from going too high when you eat carbohydrates.

There are also short-acting insulins that work slightly less quickly than rapid-acting insulins. These are usually taken about 30 minutes before meals.

There are also intermediate-acting insulins and long-acting insulins. These work more slowly and last for longer. They're taken once or twice a day to give you the background insulin you need when you're not eating.

If you take rapid-acting insulin, you'll usually need to take an intermediate or long-acting insulin as well, unless you use an insulin pump.

There are also biphasic (mixed) insulins that contain a mixture of rapid or short-acting insulin and longer-acting insulin.

Speak to your doctor or diabetes nurse if you think the type of insulin you're taking is not working well to keep your blood glucose levels stable.

Metformin is usually the first choice of medicine for type 2 diabetes.

Other medicines used to treat type 2 diabetes include:

• alogliptin
• dapagliflozin
• empagliflozin
• gliclazide
• glimepiride
• pioglitazone
• saxagliptin
• sitagliptin

These medicines are all taken as tablets.

There are also other medicines taken as injections, such as semaglutide, dulaglutide, liraglutide and exenatide.

Some people with type 2 diabetes find that their diabetes medicines stop working as well after a couple of years. This can be because the pancreas begins to make less insulin or the body becomes more resistant to the insulin it makes.

Many people with type 2 diabetes need to take a combination of different medicines to manage their blood glucose levels. Eventually some people need to take insulin because their pancreas is not making enough insulin itself.

Often insulin is used as well as the other medicines, but sometimes people will be able to reduce the number of other medicines by carefully adjusting their dose of insulin to manage their blood glucose without causing hypos.

If you have diabetes, you're entitled to free prescriptions for all of your medicines, not just your diabetes ones.

To claim your free prescriptions, you'll need to have a medical exemption certificate.

The application form for the medical exemption certificate is called FP92A. You can get this from your GP surgery.

You'll need to fill in the form, then your doctor will sign it and send it off.

When you first start taking insulin you may notice that you start to put on weight. This is because of the way insulin works to use glucose from food to produce energy and store any extra as fat.

You might have also lost weight before your diagnosis, and so you might put some weight back on once your blood glucose is back within target.

If you're concerned about putting on weight, talk to your healthcare team who can advise on diet, lifestyle and adjusting your insulin dose as you change your diet.

Having a healthy weight and eating a balanced diet can help with symptoms of type 2 diabetes and gestational diabetes.

Make sure that the surgical team knows you're taking insulin before you have any surgical procedure. They'll tell you whether you need to adjust your dose before the procedure and what to expect afterwards for your doses and testing your blood glucose levels.

Always take your insulin to hospital with you, and tell the staff what types of insulin you take and your usual doses.

Rapid-acting insulin can be used in an insulin pump.

Insulin pumps may be available on the NHS to people aged 12 years old and over with type 1 diabetes who either:

• have frequent problems with hypos, and whose hypos are hard to predict
• have high blood sugar levels despite carefully managing their diabetes and taking insulin several times a day – this is defined as an HbA1c level of 8.5% (or 69mmol/mol) or higher

For children under 12 years old, insulin pumps may be available if having several injections a day is not practical. However children with insulin pumps are expected to have a trial of using insulin pens when they're between 12 and 18 years old, to see whether they can switch.

If you have type 2 diabetes or gestational diabetes, you will not usually be eligible for an insulin pump from the NHS.

If you're interested in switching to an insulin pump and think you meet the criteria, discuss this with your diabetes specialist.

Everyone who takes insulin needs to monitor their blood glucose. The kit you need to do this is available from the NHS.

For most people the target blood glucose range is between 4 and 7mmol/L, although some people are given a wider range, and slightly higher levels after eating are OK. Hypo symptoms are more likely when blood glucose falls below 4mmol/L.

How often you'll need to check your blood glucose depends on the type of diabetes you have, how carefully you need to manage your blood glucose, how often you have hypos, and how often you drive or use machinery.

You may need to check your blood glucose more often when you're ill, during pregnancy, if you're fasting, or if you're doing shift work.

You may be given a blood glucose monitor that you wear on your body, to check your blood glucose levels at any time.

You'll also be given equipment to check your blood glucose levels with a finger-prick test. This involves using a lancet and finger-prick device to get a drop of blood from your fingertip. You then use a test-strip and meter to measure the amount of glucose that is in the blood sample.

You'll be trained to do a finger-prick test when you start taking insulin. You'll also be told how to adjust your insulin dose according to the results.

Diabetes UK has more information about checking blood glucose levels.

Some people use a continuous glucose monitor (CGM) or flash monitor to check their blood glucose levels at any time.

This is a small sensor that you attach to your arm or tummy that measures how much glucose is in the fluid (interstitial fluid) under the skin. It may come with a reader or receiver that shows the results, or you can download an app to see the results on a smartphone.

With CGM, the results are sent to the receiver wirelessly every few minutes, so you can see the results at any time. Some devices can send results to an insulin pump. Most types of CGM have an alarm that can alert you when your blood glucose is too low or too high.

With a flash monitor you need to scan the sensor with your reader or smartphone to see the results.

Interstitial fluid glucose readings are a few minutes behind your blood glucose levels. This means that you'll still need to do finger-prick checks every now and then, particularly when you have a hypo.

If you have type 1 diabetes, you should be able to get a monitor on the NHS.

If you have type 2 diabetes, you should be able to get a monitor on the NHS if you take insulin at least twice a day and you meet any of these criteria:

• you have frequent or severe hypos
• you have a disability that makes it difficult to do a finger-prick test
• you need to test your blood glucose at least 8 times a day

If you have gestational diabetes, you should be able to get a monitor on the NHS if you take insulin and you have severe hypos or your blood glucose is not stable.

Speak to your doctor or diabetes specialist if you're interested in using a CGM or flash monitor and you think you meet these criteria.

Learn more about CGM and flash from Diabetes UK.

Yes, you can take insulin abroad, but you need to plan ahead. Get a letter from your GP or diabetes care team to say you have diabetes and need to take insulin and other diabetes equipment with you, such as pens and needles. You may need to pay for the letter.

You'll also need to check with the airline if you use an insulin pump or continuous glucose monitor (CGM) or flash monitor.

Use a suitable cool bag to transport your insulin safely and keep it at the right temperature. If you're flying, take your insulin in your hand luggage.

If you're crossing several time zones, get advice from your doctor or diabetes nurse on how to adjust your insulin doses.

Check how you can get insulin in the country you're visiting, and take a recent prescription with you.

Find out more about travelling with insulin from Diabetes UK.

Rapid-acting insulin will not stop any type of contraception from working, including the combined pill and emergency contraception.

But you might need a small adjustment in your insulin dose after starting contraceptive pills.

That's because contraceptive pills change how your body handles sugar.

If you drive a car you must notify the Driver and Vehicle Licensing Agency (DVLA) when you start taking insulin.

Always check your blood glucose before driving, a maximum of 2 hours before starting your journey. You'll also need to check your blood glucose every 2 hours if you're driving on a long journey.

Your blood glucose must be 5mmol/L or higher to drive. If it's between 4 and 5mmol/L, have a starchy snack before starting to drive. If it's less than 4mmol/L, treat the hypo and do not drive for at least 45 minutes after you've recovered.

Always carry glucose and your glucose meter in the car with you.

Find out more about diabetes and driving from GOV.UK.

If you ride a bike, it's important to be aware of the risk of hypos and carry glucose with you in case you feel one coming on. If you're going on a strenuous bike ride, test your blood glucose before setting off and follow the advice you've been given about adjusting your insulin dose when you're exercising.

Yes, you can drink alcohol while taking rapid-acting insulin, but it's best to drink no more than 2 units per day. A standard glass of wine (175ml) is 2.3 units. A pint of lager or beer is usually 2 to 3 units of alcohol.

Drinking more than this can increase the risk of a hypo, especially if you drink alcohol on an empty stomach. Hypos can happen up to 24 hours after drinking alcohol.

Many alcoholic drinks also contain a lot of sugar and it can be difficult to work out if you need to adjust your insulin dose with these drinks.

If you do want to drink alcohol regularly, discuss this with your doctor or diabetes nurse. Try to keep to the recommended guidelines of no more than 14 units of alcohol a week, spread over 3 days or more.

There are no foods you need to avoid because you're taking rapid-acting insulin.

However, unless you're treating a hypo it's usually best not to drink sugary drinks or fruit juices if you're feeling thirsty, as this can increase your blood glucose levels very quickly.

You should be offered appointments with a dietitian to work out a healthy balanced diet that suits your tastes and lifestyle.

It's important to eat regular meals as skipping meals can affect your blood glucose levels and the dose of insulin you need.

Be careful eating food and drink containing karela (also called bitter gourd). This is because it can lower your blood glucose levels and you may need to adjust your insulin for this. Karela is used to flavour foods such as curries like bitter gourd masala. It has a bitter taste and is also made into juice and tea.

Having a healthy, balanced diet and exercising regularly will help you keep to a healthy weight and help improve your blood glucose levels. This will help you avoid symptoms and complications of type 2 diabetes.

Your doctor or diabetes nurse can advise you on what kinds of exercise are best for you and how you can safely build up your level of exercise.

If you're doing more strenuous exercise, get advice about taking snacks or reducing your insulin dose before you exercise and checking your blood glucose levels before and after exercise.

Read more about food and keeping active if you have type 2 diabetes.

Having a healthy, balanced diet and exercising regularly will help improve your blood glucose levels. This will help you avoid symptoms and complications of gestational diabetes.

Your doctor, midwife or diabetes nurse can advise you on what kinds of exercise are best for you.

If you're doing more strenuous exercise, get advice about taking snacks or reducing your insulin dose before you exercise and checking your blood glucose levels before and after exercise.

Read more about diet and exercise if you have gestational diabetes.