説明
Dexamethasone causes dose-dependent hyperglycaemia by inducing insulin resistance and increasing hepatic glucose output, substantially increasing insulin requirements in diabetic patients.
機序
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.
臨床的意義
Steroid-induced hyperglycaemia is well-documented; insulin requirements can increase by 30–100% depending on dexamethasone dose, particularly affecting afternoon and evening glucose levels.
対処法
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.