Insulin Lispro is a rapid-acting human insulin analogue used for the control of hyperglycemia in diabetes mellitus. It is created by reversing the amino acids proline and lysine at positions 28 and 29 on the insulin B-chain. This modification reduces the molecule's tendency to self-associate into dimers and hexamers, allowing for faster absorption from subcutaneous tissue, a more rapid onset of action, and a shorter duration of effect compared to regular human insulin. It is typically administered immediately before or after meals to control postprandial glucose spikes.
Adult: Highly individualized. Typically 0.5 to 1.0 unit/kg/day, divided into pre-meal (bolus) doses. The pre-meal dose is based on carbohydrate intake, pre-meal blood glucose, and anticipated physical activity. Usually administered 0-15 minutes before or immediately after a meal.
Note: For subcutaneous injection only. Use in the abdominal wall, thigh, upper arm, or buttocks. Rotate injection sites within the same region. Inject into the subcutaneous tissue, not intramuscularly. Use appropriate insulin syringes, pens, or pumps. Do not mix with other insulins in the same syringe unless specifically indicated (e.g., with specific premixed formulations). Visually inspect before use.
Insulin Lispro binds to the alpha-subunit of the transmembrane insulin receptor, which is a tyrosine kinase. This binding triggers autophosphorylation of the receptor and subsequent phosphorylation of intracellular signaling proteins (IRS-1, Shc). This cascade activates downstream pathways (PI3-kinase/Akt and MAPK), leading to the translocation of glucose transporter type 4 (GLUT4) to the cell membrane, facilitating cellular uptake of glucose. It also promotes glycogen, fatty acid, and protein synthesis while inhibiting gluconeogenesis, glycogenolysis, lipolysis, and proteolysis.
Pregnancy: Pregnancy Category B. Insulin is the drug of choice for glycemic control in pregnant women with diabetes (pre-existing or gestational). Requirements may decrease in first trimester and increase significantly in second and third trimesters. Close monitoring of blood glucose is essential.
Driving: Caution advised. Hypoglycemia can impair concentration and reaction time. Patients should check blood glucose before driving and have a fast-acting carbohydrate source available.
| Corticosteroids (e.g., Prednisolone) | Antagonize insulin effect, leading to hyperglycemia and increased insulin requirement. | Major |
| Beta-blockers (e.g., Propranolol) | May mask tachycardia as a sign of hypoglycemia and impair counter-regulatory response. Can also potentiate hypoglycemia. | Major |
| Thiazide Diuretics (e.g., Hydrochlorothiazide) | May cause hyperglycemia, increasing insulin requirement. | Moderate |
| Alcohol | Potentiates hypoglycemic effect and can impair gluconeogenesis, increasing risk of severe hypoglycemia. | Major |
| MAO Inhibitors, ACE Inhibitors | May potentiate hypoglycemic effect. | Moderate |
| Oral Hypoglycemic Agents (e.g., Sulfonylureas) | Additive hypoglycemic effect, increasing risk of hypoglycemia. | Major |
| Octreotide, Lanreotide | Alters glucose metabolism; may increase or decrease insulin requirement. | Moderate |
| Atypical Antipsychotics (e.g., Olanzapine) | May cause hyperglycemia, increasing insulin requirement. | Moderate |