PEOPLE with diabetes may need different types of insulin at certain times of the day to help them manage their glucose intake from food. There are four types of insulin – rapid-acting, short-acting, intermediate-acting and long-acting.
Rapid-acting insulin gets into the blood within 15 minutes of injection and reaches maximum activity 30 to 90 minutes later. It has to be administered either five to 15 minutes before eating, while eating, or immediately after eating. It can last from two to five hours but might not last long enough to control blood glucose levels between meals. Thus, a person might need to complement it with a long-acting insulin. The advantage of rapid-acting insulin is the ease of fitting it around mealtimes and controlling peaks in blood glucose levels that happen immediately after eating.
Short-acting insulin (also known as soluble, or regular insulin) usually reaches the blood within 30 minutes of injection and peaks two to four hours later. They are usually taken 30-45 minutes before a meal and will cover the rise in blood glucose that occurs after eating. They can last for up to eight hours.
Intermediate-acting insulin works over several hours to keep blood glucose under control between meals. This type of insulin usually has a peak of activity between four and 12 hours after injecting, and can last from eight to 24 hours. They are often used in combination with short-acting insulin.
Long-acting insulin has no peak or a very small peak 10 to 16 hours after injection. Some long-term insulin mimics a normal body’s insulin secretion and is released gradually into the blood after administration. This helps prevent the incidence of hypoglycaemia (low levels of sugar in the blood).
Aim of insulin therapy
The primary aim in the management of diabetes is to keep blood glucose levels as close as possible to normal levels. However, insulin therapy can sometimes result in hypoglycaemia. This occurs when the level of glucose in the blood falls too low.
In a healthy body, the production of insulin is regulated (by a hormone) and there is a balance between glucose converted into energy and glucose remaining in the bloodstream. However, in people with diabetes who are receiving treatment with insulin, the insulin levels is not regulated by the body’s mechanism. The insulin continues to convert glucose until the levels left in the blood fall too low. It often happens when a person administers shorter-term insulin without having something to eat before or after the jab.
During hypoglycaemia, a diabetic person will experience a number of distressing symptoms - feeling shaky, sweaty, tingling in lips, going pale and feeling confused – as his/her body tries to raise the blood glucose level. It can also cause a person to faint.
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