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High risk medicines: insulin

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Insulin is a hormone which helps to regulate metabolism and lowers blood glucose levels.

It is most often prescribed for patients with type 1 diabetes. Sometimes it is also used to treat type 2 diabetes. This would be when other methods have not been able to control blood glucose concentrations.

Insulin is prescribed in ‘units’. There are many different preparations available in the UK. They all have different durations of action (short, intermediate and long-acting).

Insulin is a protein, so stomach enzymes prevent it from working if taken orally. It is usually given by sub-cutaneous injection. There are many devices available for administering insulin. They are often designed for ease of administration by patients and carers.


Care plan

You should have a person-centred care plan for anyone using insulin. This should include their insulin needs, arrangements for monitoring and risk assessments. It should also include details of the person responsible for:

  • managing their diabetic care
  • administering their insulin

Insulin 'passports'

Insulin passports help reduce administration errors. They provide a record of a person’s current insulin preparations and dose schedule. They also include other patient information such as emergency contact or treatment information.


Insulin can cause hypoglycaemia (low blood glucose levels). Some people might need to take emergency ‘rescue’ medicine. For example, oral glucose or glucagon may need to be prescribed and supplied. If you supply a 'rescue' medicine, record details in the person’s care plan. The timing of a meal is important in helping to avoid fluctuations in blood glucose levels.

Be aware of the symptoms of mild hypoglycaemia. They can include hunger, anxiety or irritability, palpitations, sweating, or tingling lips. If severe it can lead to convulsions, loss of consciousness, coma and death.

Glucose drinks

Be aware of changes to the carbohydrate content of drinks that contain glucose. For example, Lucozade® Energy Original now has half the sugars than before. Check individual product labels for glucose content.

Storing insulin

If not stored correctly, insulin products can lose their effectiveness. Because insulin is a protein, it may break down if frozenWhen thawed it could cause blood glucose levels to increase. Refer to the package/label for each product.

You usually need to refrigerate insulin preparations. When in use, you can store them at room temperature for limited periods. Record the date when you first open or use an insulin product. This helps when checking how long the insulin has been out of the refrigerator. Find out more about storing medicines in a fridge.


Some multi packs of insulin pens are supplied in boxes labelled with the person’s name. Sometimes the supplying pharmacist will label the individual pens. If pens are not labelled, make sure it's clear who the insulin pens belong to.

Accurate recording

When prescribing, transcribing or recording insulin do not abbreviate the word 'unit'. Always write it in full. Abbreviations (such as ‘u’) can be confused with a zero (particularly if handwritten). This could have serious consequences.

Monitoring blood glucose levels

Make arrangements to check the blood glucose levels for each person. Record any actions you need to take. Some people can do this for themselves. Make it clear who will administer and monitor. Record this should in the person’s care plan. Only trained competent staff should be responsible for administering insulin or monitoring blood glucose levels.

Blood glucose levels will determine whether insulin doses need to change and by how much. For people whose diabetes is difficult to control, insulin doses may be on a varying dose scale. Blood glucose levels will determine how many units they take each time.

Records need to show how much insulin has been given on each occasion. District or community nurses may keep their own records. Details must also be available in people’s care plans.

Administering insulin

Some people will be able to administer their own insulin. Assess and record the risk to check that they are able to do this safely (a risk assessment). If not, nurses or trained care staff should administer the insulin. Care staff must receive specialist training to administer insulin as a delegated task and should be assessed as competent to administer insulin to the named person or people. If community nurses administer insulin, records must also be available to care home staff

Rotate the injection site to avoid local reactions to the insulin. Common sites include upper arms, thighs, buttocks and abdomen. When nursing or care staff administer insulin, record where they injected the insulin each time.

A variety of hypodermic needles, syringes, lancets and other accessories can help with administering and monitoring insulin. They are usually available on prescription. Always measure insulin with an insulin syringe or appropriate commercial insulin device. Devices (such as insulin pens) are marked in units. Never measure insulin with an intravenous syringe marked in millilitres (ml). Never extract insulin from pen devices or cartridges. This can lead to serious errors.

Lancets are for single use only. Lancets and finger pricking devices should be person specific.

Dispose of sharps in a suitable container and make arrangements to dispose these containers.

Last updated:
02 December 2019