Pharmacokinetics of Insulin

Pharmacokinetics of Insulin

1. Breakdown and Administration

   • Insulin is metabolized in the gut, liver, and kidneys (GLK).

   • Administered via injection due to being broken down by gastrointestinal enzymes.

2. Half-Life

   • The half-life (t1/2) of insulin is 3 to 5 minutes.

3. Metabolism

   • Insulin is metabolized to inactive and 3 peptide chains predominantly by hepatic/renal insulinases (insulin glutathione transhydrogenase).

   • Approximately 60% of insulin from the pancreas is degraded in the liver before entering systemic circulation (presystemic metabolism).

4. Role of the Kidneys

   • The kidneys play a significant role in insulin metabolism.

   • Patients with renal impairment may have a reduced requirement for insulin.

5. Liver Function

   • Diabetes does not result from increased hepatic destruction of insulin.

   • In cirrhosis, the liver fails to inactivate insulin, leading to a risk of hypoglycemia.