Pharm 101: Insulin
Class
Endogenous hormone
Mechanism of action
- Acts on ligand-regulated tyrosine kinase receptor
- Promotes uptake of glucose from blood into tissues, especially fat, liver, skeletal muscle
- Promotes glycogen synthesis
Formulations
- IV or SC administration
- Rapid and short acting:
- Clear solution, neutral pH
- Rapid onset, short duration
- e.g. insulin lispro
- Short-acting regular soluble insulin is used for IV infusion, as it immediately dissociates on dilution and thus is able to be more precisely delivered
- Intermediate acting:
- Turbid solution, neutral pH
- Protamine in phosphate buffer (NPH) to prolong action
- e.g. insulin aspart protamine
- Long-acting:
- Clear solution
- Slow onset, prolonged action
- Daily administration mimics basal insulin secretion
- e.g. insulin glargine
Clinical uses
- Regulation of blood glucose:
- Combinations of insulins with different durations of actions (see below) aim to replace basal insulin requirement (50%) and meal requirement (50%) to achieve optimal glycaemic control
- Hyperkalaemia
- Calcium channel blocker overdose
Adverse effects
- Hypoglycaemia
- Hypoglycaemia unawareness
- Allergy (usually due to non-insulin contaminants)
- Immune insulin resistance
- Lipodystrophy at injection sites
References
- Katzung BG. Basic and Clinical Pharmacology. 14e. 2018
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