Moderate
Dexamethasone × Metformin
Glucocorticoids×Biguanides. Oral antihyperglycemic agents
Mechanism
Dexamethasone stimulates gluconeogenesis and reduces tissue insulin sensitivity. The glycaemic effect is stronger than with prednisolone due to long half-life and high potency.
Symptoms
Return of thirst and polyuria, rising fasting glucose, fatigue. In type 2 diabetes, possible decompensation with HbA1c rise of 0.5–1.5%.
Management
For short dexamethasone pulses (1–3 days, e.g. cerebral oedema or post-chemotherapy), no metformin adjustment needed — transient hyperglycaemia is tolerated. For long-term therapy, increase metformin or add long-acting insulin. Check glucose twice daily in the first week.
Check the full regimen, not just this pair
Opens the checker with these two drugs prefilled. Add the rest of the regimen and recompute additive risks.