Singapore Drugs Database

Indication

For the treatment of Type 1 or 2 diabetes mellitus. To be used in conjunction with an intermediate or long-acting insulin except when used in a continuous insulin infusion pump.

Mechanism of Action

Insulin lispro binds to the insulin receptor (IR), a heterotetrameric protein consisting of two extracellular alpha units and two transmembrane beta units. The binding of insulin to the alpha subunit of IR stimulates the tyrosine kinase activity intrinsic to the beta subunit of the receptor. The bound receptor autophosphorylates and phosphorylates numerous intracellular substrates such as insulin receptor substrates (IRS) proteins, Cbl, APS, Shc and Gab 1. Activation of these proteins leads to the activation of downstream signaling molecules including PI3 kinase and Akt. Akt regulates the activity of glucose transporter 4 (GLUT4) and protein kinase C (PKC), both of which play critical roles in metabolism and catabolism. In humans, insulin is stored in the form of hexamers; however, only insulin monomers are able to interact with IR. Reversal of the proline and lysine residues at positions B28 and B29 of native insulin eliminates hydrophobic interactions and weakens some of the hydrogen bonds that contribute to the stability of the insulin dimers that comprise insulin hexamers. Hexamers of insulin lispro are produced in the presence of zinc and m-cresol. These weakly associated hexamers quickly dissociate upon subcutaneous injection and are absorbed as monomers through vascular endothelial cells. These properties give insulin lispro its fast-acting properties.

Pharmacokinetics

Absorption

Rapidly absorbed following subcutaneous administration. It is also absorbed more quickly than regular human insulin. Peak serum levels occur 30-90 minutes after injection in healthy subjects. Absorption also differs depending on the site of injection. After insulin lispro was administered in the abdomen, serum drug levels were higher and the duration of action was slightly shorter than after deltoid or thigh administration. Bioavailability, 0.1 - 0.2 unit/kg = 55% - 77%.

Distribution

When administered intravenously as bolus injections of 0.1 and 0.2 U/kg dose in two separate groups of healthy subjects, the mean volume of distribution of insulin lispro appeared to decrease with increase in dose (1.55 and 0.72 L/kg, respectively).

Metabolism

Insulin is predominantly cleared by metabolic degradation via a receptor-mediated process.

Elimination

Clearance

Clearance is dose dependent. When a dose of 0.1 unit/kg and 0.2 unit/kg were administered intravenously, the mean clearance was 21.0 mL/min/kg and 9.6 mL/min/kg respectively.

Toxicity

Inappropriately high dosages relative to food intake and/or energy expenditure may result in severe and sometimes prolonged and life-threatening hypoglycemia. Neurogenic (autonomic) signs and symptoms of hypoglycemia include trembling, palpitations, sweating, anxiety, hunger, nausea and tingling. Neuroglycopenic signs and symptoms of hypoglycemia include difficulty concentrating, lethargy/weakness, confusion, drowsiness, vision changes, difficulty speaking, headache, and dizziness. Mild hypoglycemia is characterized by the presence of autonomic symptoms. Moderate hypoglycemia is characterized by the presence of autonomic and neuroglycopenic symptoms. Individuals may become unconscious in severe cases of hypoglycemia. Rare cases of lipoatrophy or lipohypertrophy reactions have been observed.

Active Ingredient/Synonyms

Insulin lispro (genetical recombination) | Insulin lispro (rDNA origin) | Insulin lispro protamine | Insulin lispro protamine recombinant | Insulin lispro recombinant | Insulin,lispro,human/rDNA | Insulin,lispro,protamine/rDNA | Insulin Lispro |