insulin lispro
rapid-acting insulin analogue· Brands: Humalog, Admelog, LyumjevIVSC
Mechanism of action
Insulin lispro is a rapid-acting insulin analogue. It binds to the insulin receptor, a receptor tyrosine kinase, on muscle, adipose tissue and hepatocytes. This activates intracellular signalling cascades that promote translocation of glucose transporters to the cell membrane, increasing glucose uptake, and stimulates glycogen synthesis and lipogenesis. It also suppresses hepatic gluconeogenesis and glycogenolysis. The amino acid sequence modification (proline to lysine at B28 and lysine to proline at B29) reduces the tendency for hexamer formation, facilitating more rapid absorption after subcutaneous injection compared with regular human insulin.
Pharmacokinetics
Following subcutaneous injection, insulin lispro is rapidly absorbed with an onset of action in 10 to 30 minutes, peak serum concentration in 30 to 90 minutes, and duration of action of 2 to 4 hours. It is metabolised by insulin-degrading endopeptidases in the liver, kidney and muscle, and systemic insulin clearance is mediated mainly by renal degradation. Bioavailability is similar to regular insulin. The time-action profile can be affected by the injection site, dose, temperature and exercise. It is also given intravenously in some clinical settings for rapid control.
Indications & dosing
Type 1 diabetes mellitus
Given with a basal insulin. Adjust dose according to carbohydrate intake and blood glucose.
- adult · SC: 0.1–0.2 units/kg Before meals · Given with a basal insulin. Adjust dose according to carbohydrate intake and blood glucose.
Type 2 diabetes mellitus
Starting dose; titrate based on glucose response. May be used with other antidiabetic agents.
- adult · SC: 4–6 units Before meals · Starting dose; titrate based on glucose response. May be used with other antidiabetic agents.
Gestational diabetes mellitus
Used when oral therapy is inadequate. Doses are individualized and adjusted by a specialist.
- adult · SC: 0.1–0.2 units/kg Before meals · Used when oral therapy is inadequate. Doses are individualized and adjusted by a specialist.
Contraindications & precautions
- Hypoglycemia · Insulin lispro is contraindicated during episodes of hypoglycaemia.
- Hypersensitivity to insulin lispro or any excipients · Allergic reactions can be severe, including anaphylaxis.
- Monitor blood glucose regularly, especially when initiating or changing therapy.
- Rotate injection sites to reduce the risk of lipodystrophy.
- Adjust dose during intercurrent illness, changes in diet or activity, or renal/hepatic impairment.
- Be aware of the rapid onset and short duration of action; instruct patients to time meals appropriately.
- Never mix insulin lispro with other insulins in the same syringe unless specifically prescribed.
- Caution in patients with hypoglycaemia unawareness or frequent hypoglycaemia; consider intensifying monitoring.
Adverse effects
- Hypoglycaemiaserious
- Weight gain
- Injection site reactions
- Lipodystrophy
- Hypokalaemiaserious
- Allergic reactions including anaphylaxisserious
Renal & hepatic adjustment
- eGFR 0–29: Insulin requirements may be significantly reduced in severe renal impairment; monitor blood glucose closely and adjust doses to avoid hypoglycaemia.
- eGFR 30+: No specific dose adjustment defined; dose may need to be reduced as renal function declines. Monitor glycaemia.
- Hepatic impairment (severe): Insulin requirements may be reduced; monitor blood glucose closely and adjust doses.
- Hepatic impairment (moderate): No specific dose adjustment defined; consider closer glycaemic monitoring.
Monitoring, pregnancy & toxicity
- Blood glucose (fasting and postprandial) · At least 4 times per day or as clinically indicated
- HbA1c · Every 3 months
- Hypoglycaemia symptoms · At each review
- Weight · At each visit
- Injection site reactions · At each visit
- Serum potassium · Especially if switching from other insulin or with renal impairment
- Pregnancy: Insulin lispro is the preferred treatment for diabetes mellitus during pregnancy. Doses may need to be adjusted due to changing insulin requirements. Close glycaemic control is essential.
- Toxicity: Hypoglycaemia · Mild to moderate: oral glucose. Severe: glucagon intramuscular injection or intravenous glucose (e.g. 10% or 50% dextrose) per local protocol.
- Toxicity: Hypokalaemia · May occur with large doses; monitor serum potassium and correct if needed.
Antidotes & reversal
- Dextrose 10-50% IV · Rapid-acting analogue - observe for recurrent hypoglycaemia for several hours after correction.
Clinical notes
Insulin lispro is used to control postprandial hyperglycaemia in patients with diabetes mellitus. It should be administered immediately before or shortly after a meal, typically within 15 minutes before eating. It is suitable for use in continuous subcutaneous insulin infusion (CSII) pumps and may be used with a longer-acting insulin to provide basal coverage. Hypoglycaemia is the most common adverse effect; patients should be educated on recognition and management. The risk of hypoglycaemia is increased if meals are delayed or missed. Dose adjustments may be needed in renal or hepatic impairment. It can be given by subcutaneous injection or, in hospital settings, by intravenous infusion. Different preparations have different concentrations; always check labels.
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BNF; local formulary