Insulin therapy

Question 1

What is the first-line treatment for insulin therapy in both adults and children?

Answer 1

Adults - multiple daily injection basal-bolus insulin regimens, twice daily insulin detemir as long-acting basal insulin, or once daily insulin glargine.

Children - Multiple daily injection basal-bolus insulin regimens. If multiple injections are inappropriate or difficult to administer then use continuous subcutaneous insulin infusion therapy (insulin pump).

Question 2

What are the two types of insulin categorised by function?

Answer 2

1) basal (long-acting insulin), 2) prandial (rapid-acting or “mealtime” insulin).

Question 3

When is basal insulin injected?

Answer 3

Basal insulin is injected once/twice daily to provide a constant level of insulin action throughout the day.

Question 4

Name examples of rapid-acting insulin.

Answer 4

insulin, insulin aspart, insulin glulisine, insulin lispro.

Question 5

Name examples of short-acting insulin.

Answer 5

Iletin II, Humulin R, Novolin R

Question 6

Name examples of intermediate-acting insulin.

Answer 6

isophane insulin/biphasic isophane insulin, biphasic insulin aspart, biphasic insulin lispro.

Question 7

Name examples of basal/long-acting insulin.

Answer 7

protamine zinc insulin, insulin zinc suspension, insulin detemir, insulin glargine, insulin degludec.

Question 8

What is the duration of action and goal of rapid-acting insulin?

Answer 8

Onset: 15 minutes
Peak: 1-3 hours
Duration: 3-5 hours.

Goal - minimise rise in blood sugar which follows after eating.

Question 9

What is the duration of action and goal of short-acting insulin?

Answer 9

Onset: 30-60 minutes
Peak: 2-3 hours
Duration: 5-7 hours.

Goal - works as a natural insulin and increases overall ability for the body to uptake glucose.

Question 10

What is the duration of action and goal of Intermediate-acting insulin?

Answer 10

Onset: 60-90 minutes
Peak: 8-12 hours
Duration: 18-24 hours.

Goal - to control blood sugar levels after eating. Helps regulate blood sugars throughout the day.

Question 11

What is the duration of action and goal of long-acting insulin?

Answer 11

Onset: 4-8 hours
Peak: 10-30 hours
Duration: 36+ hours.

Goal - consistent delivery of activity throughout the day; no peak activity.

Question 12

What is the duration of action and goal of analogues?

Answer 12

Onset: 1.1 hours
Peak: None
Duration: 24 hours.

Goal - Analogue insulin is a sub-group of human insulin. Analogue insulin is laboratory grown but genetically altered to create either a more rapid acting or more uniformly acting form of the insulin.

Question 13

What is the frequency of use of rapid-acting insulin?

Answer 13

Usually taken before or with a meal.

Question 14

What is the frequency of use of short-acting insulin?

Answer 14

Usually taken before meals.

Question 15

What is the frequency of use of intermediate-acting insulin?

Answer 15

Commonly used in conjunction with short-acting insulin.

Question 16

What is the frequency of use of long-acting insulin?

Answer 16

Either once or twice daily.

Question 17

Which insulins have an increased risk of hypoglycaemia?

Answer 17

Rapid-acting and intermediate-acting insulins.

Question 18

What are the indications of insulin?

Answer 18

diabetes mellitus (all), diabetic ketoacidosis (insulin IV), diabetes during surgery (insulin IV).

Question 19

What is the mechanism of action of insulin?

Answer 19

Insulin is a fuel-storing hormone and regulates glucose metabolism to produce energy for cellular functions. Insulin secretion is increased in response to increased glucose plasma concentration. There are two phases - initial rapid response (release of pre-formed and stored insulin), and longer lasting phase which consists of the synthesis and release of new insulin. In diabetics, injected insulin works in the same way when injected into the subcutaneous fat and slowly absorbed into the bloodstream.

Insulin targets liver, muscle and fat cells via insulin receptors, resulting in the uptake of glucose from the plasma into the target cells. This leads to a reduction in plasma glucose concentration. It has an effect on fat metabolism, as deficiency in insulin leads to incomplete fat metabolism and production of ketones. It effects protein metabolism by increasing transport of amino acids into cells and synthesising protein within the cells. It also increases gluconeogenesis in the liver and decreases glycogen breakdown. There are also long-term effects of insulin which are mediated via effects on DNA and RNA function.

Question 20

What are the common/very common side effects of insulins?

Answer 20

fat hypertrophy at injection site, local reactions at injection site, transient oedema, hypoglycaemia.

Question 21

What are the monitoring requirements of patients on insulin therapy?

Answer 21

Regular monitoring of blood glucose concentrations. Adults - maintain blood glucose concentration between 4-9 mmol/litre (4-7 mmol/litre before meals, less than 9 mmol/litre after meals). Children - 4-8 mmol/litre before meals, less than 10mmol/litre after meals. Strenous efforts must be made to prevent it falling below 4 mmol/litre.

Measure HbA1c levels every 3–6 months in patients with type 1 diabetes.

Question 22

What is an HbA1c test and why is it useful for clinicians?

Answer 22

The term HbA1c refers to glycated haemoglobin. It develops when haemoglobin, a protein within red blood cells that carries oxygen throughout the body, joins with glucose in the blood, becoming ‘glycated’.
By measuring glycated haemoglobin (HbA1c) healthcare professionals are able to get an overall picture of what average blood sugar levels have been over a period of weeks/months. Because red blood cells in the human body have an average lifespan of 8-12 weeks, measuring glycated haemoglobin (or HbA1c) can be used to reflect average blood glucose levels over that duration, providing a useful longer-term measurement of blood glucose control.

Question 23

What is the patient/carer advice for insulin therapy?

Answer 23

All patients and carers need to be trained to monitor blood glucose concentrations, how to adjust insulin dose according to carbohydrate intake, how to regulate carbohydrate intake, as well as ensuring intake is adequate to allow normal growth and development whilst preventing obesity, and how to avoid hypoglycaemia. All drivers must be warned about effects of hypoglycaemia on driving. Insulin passports/booklets should be given to all patients.