4. Example - Insulin
Insulin is a hormone that is made in the body (in the pancreas) and controls the level of sugar in the blood. Insulin acts like an enzyme-key, see section 8. When the level of blood sugar increases (e.g. early in the morning or after a meal), insulin is released from the pancreas, which causes other cells and tissues to take up sugar to produce energy. People with diabetes mellitus cannot use sugar properly to produce energy. Patients with type 1 diabetes mellitus (formerly known as insulin-dependent diabetes mellitus) are unable to produce their own insulin, so they are prescribed the biologic medicinal form of insulin to treat their disease. Patients with type 2 diabetes mostly do produce insulin themselves but their cells and tissues may be unable to take up sugar in response to insulin (increased insulin resistance). People with type 2 diabetes use tablets to regulate their diabetes, if they produce enough insulin themselves, but a minority require treatment with medicinal insulin later on.
Insulin is injected under the skin using one of several possible devices, including single-use syringes, insulin pumps or insulin pens, administered by the patients themselves.
There is a range of different types of insulin. Regular insulin is the same as that produced by the body. Some of the most recent insulin types are produced by chemical modification of a substance produced by living cells, i.e. could be said to be semi-synthetic molecules. Type 1 diabetes mellitus is a lifelong (chronic) condition that requires continual insulin treatment.
Patients inject insulin up to eight times a day by syringe or pen or they use an insulin pump that delivers insulin continuously. Long acting insulin can be taken one to two times a day to regulate the body’s basic homeostasis, and in addition, patients take fast acting insulin before each meal to account for additional carbohydrates that enter the bloodstream. An insulin pump is adjusted individually to each patient’s needs and delivers insulin every 5 minutes using only fast acting insulin.
The benefits of insulin treatment are that it allows patients with diabetes mellitus to keep their blood sugar levels in a normal range and to reduce the risk of diabetes-related complications, such as cataracts (cloudy patches in the lens of the eye), kidney disease and stroke. The most common and serious side effect of insulin is low blood sugar (hypoglycaemia), which can lead to confusion, sweating, irregular heartbeat and, if untreated, coma, seizures and death.