Will administering dexamethasone (Dexamethasone) interact with hydrocortisone (Hydrocortisone) 100mg given prior to induction?

No Clinically Significant Interaction Between Hydrocortisone and Dexamethasone

You can safely administer dexamethasone after giving hydrocortisone 100 mg prior to induction, as both are glucocorticoids that work through the same mechanism and do not have a harmful drug-drug interaction. 1

Why This Combination is Safe

• Both hydrocortisone and dexamethasone are glucocorticoids that bind to the same glucocorticoid receptors and produce similar anti-inflammatory and immunosuppressive effects 2
• Dexamethasone has minimal sodium-retaining properties compared to hydrocortisone, making it pharmacologically compatible 2
• UK guidelines explicitly state that dexamethasone 6-8 mg IV can be used as an alternative to hydrocortisone for perioperative steroid coverage, indicating these agents are interchangeable in this context 1

Guideline-Supported Practice

• The Association of Anaesthetists, Royal College of Physicians, and Society for Endocrinology UK guidelines specifically note that for major surgery, either hydrocortisone 100 mg at induction followed by continuous infusion OR dexamethasone 6-8 mg IV can be used, with dexamethasone providing sufficient coverage for 24 hours 1, 3
• This demonstrates that switching between or combining these agents in the perioperative period is an accepted practice 1

Important Caveats

• The main consideration is not interaction but rather redundancy: if you already gave hydrocortisone 100 mg, adding dexamethasone may provide excessive glucocorticoid coverage unless there is a specific indication (such as antiemetic effect or prolonged coverage) 1
• Dexamethasone 8 mg is approximately equivalent to 200 mg of hydrocortisone in anti-inflammatory potency, so you would be providing substantial additional steroid coverage 2
• If the indication for dexamethasone is for postoperative nausea/vomiting prophylaxis, this is reasonable as dexamethasone 8 mg has proven efficacy for this indication 1

Clinical Decision Algorithm

• If steroid coverage is the goal: The hydrocortisone 100 mg you already gave is adequate; additional dexamethasone is unnecessary unless you want extended 24-hour coverage without continuous infusion 1, 3
• If antiemetic effect is the goal: Dexamethasone 8 mg can be given for postoperative nausea/vomiting prevention, and this is safe despite prior hydrocortisone 1
• Monitor for: Hyperglycemia, as the combined glucocorticoid load may be substantial, particularly in diabetic patients 1