Description
Dexamethasone causes dose-dependent hyperglycaemia by inducing insulin resistance and increasing hepatic glucose output, substantially increasing insulin requirements in diabetic patients.
Mécanisme
Glucocorticoids activate gluconeogenic enzymes in the liver, suppress GLUT4 translocation in peripheral tissues, and impair insulin receptor signalling, resulting in peripheral insulin resistance and postprandial hyperglycaemia.
Signification clinique
Steroid-induced hyperglycaemia is well-documented; insulin requirements can increase by 30–100% depending on dexamethasone dose, particularly affecting afternoon and evening glucose levels.
Prise en charge
Increase insulin glargine dose (and consider adding short-acting insulin) when dexamethasone is initiated; monitor blood glucose at least 4 times daily; reduce insulin dose when dexamethasone is tapered to avoid rebound hypoglycaemia.