There are four types of insulin preparation:
- Bovine (from cattle pancreas)
- Porcine (from pig pancreas)
- Analogue (very fast acting)
What insulin does
Normally produced by the beta cells in the islets of Langerhans of the pancreas, insulin acts by lowering blood glucose concentration, and by stimulating the storage of glucose in the liver and in adipose tissue. It is responsible for initiating the storage of amino acids in the muscle in the form of protein. It reduces the breakdown of triglycerides, glycogen and protein and the conversion of amino acids to glucose. It is used as a drug in the following patients:
- Those with insulin-dependent diabetes mellitus (Type 1)
- Those with non-insulin dependent diabetes mellitus (Type 2), when the condition is inadequately controlled by diet and/or oral hypoglycaemics
- Patients with gestational diabetes mellitus
- For the management of diabetic ketoacidosis
- To treat nonketotic, hyperglycaemic coma.
Common insulin types
Types include Human Actrapid, Humulin S, Hypurin Bovine Neutral and Hypurin Porcine Neutral.
- Clear solution that should be discarded if cloudy
- Generally given subcutaneously (SC), but can be given intravenously (IV) or intramuscularly (IM) in emergencies
- Commonly used in infusion pumps
- The main type of insulin used in stabilising diabetes.
Types include: Isophane insulins, such as Humulin I, Hypurin Bovine Isophane, Hypurin Porcine Isophane, Human Insulatard ge, Insuman Basal and also Insulin Zinc Suspensions (amorphous and crystalline), such as Humulin Lente, Human Monotard HM, Humulin Zn, Human Ultratard and Hypurin Bovine Lente
- White, cloudy solution
- Available as both intermediate and long-acting
- Slow-release, with prolonged action due to zinc or protamine content
- Not an emergency treatment, so never given IV or IM. For SC use only.
Types include Human Mixtard 30, Humulin M3 and Hypurin Porcine 30/70 Mix.
- Contains fixed proportions of neutral soluble insulin and isophane insulin that give biphasic action
- Stable premixed solutions
- Speed of onset of action depends on the proportion of soluble insulin.
Adverse effects of insulin
Low blood glucose produced by an excess of insulin.
- Early signs include tremor, sweating, hunger, palpitations, dizziness, headache, pallor and tachycardia
- Can lead to drowsiness, slurred speech, blurred or double vision, confusion
- If untreated, may eventually lead to convulsions and coma.
- Erythema or pruritus at injection site
- General allergic reactions (very rare), such as urticaria, angioneurotic oedema or anaphylactic shock
- Lipodystrophy at injection site (temporary provided site is changed regularly).
- Alcohol and beta-blockers, such as metoprolol, oxprenolol, pindolol and propranolol may heighten the effects of insulin.
Havard, M., Tiziana, A. (1994) A Guide to Nursing Drugs (4th edn). London: Churchill Livingstone.
MIMS. (September 2001).London: Haymarket Medical.