Do hydrocortisone (corticosteroid) injections decrease sodium levels in the blood?

Hydrocortisone Injections and Sodium Levels in the Blood

Hydrocortisone injections do not decrease sodium levels in the blood but rather tend to increase serum sodium levels through their mineralocorticoid effects. 1

Mechanism of Action

• Hydrocortisone (cortisol) has both glucocorticoid and mineralocorticoid properties that affect sodium and water balance 1
• When used as replacement therapy in adrenal insufficiency, hydrocortisone promotes sodium retention in the kidneys 1
• Hydrocortisone prevents excess sodium excretion and reduces urine volume, helping to maintain normal serum sodium levels 2

Clinical Evidence

• In patients with aneurysmal subarachnoid hemorrhage (SAH), hydrocortisone (1200 mg/day) has been shown to prevent hyponatremia by reducing natriuresis 2
• Studies demonstrate that hydrocortisone administration maintains targeted serum sodium levels and normal plasma osmolarity 2, 3
• In patients with primary adrenal insufficiency, hydrocortisone replacement helps avoid salt craving and prevents sodium depletion 1

Physiological Effects

• Hydrocortisone promotes sodium retention and potassium excretion through its mineralocorticoid activity 1
• Even synthetic glucocorticoids with less mineralocorticoid activity (prednisolone, methylprednisolone, triamcinolone, dexamethasone) can increase blood pressure without causing sodium retention 4
• In the syndrome of inappropriate antidiuretic hormone (SIADH), glucocorticoids can actually increase serum sodium by reducing ADH secretion 5

Clinical Applications

• In neurosurgical patients with hyponatremia, hydrocortisone (1200 mg/day) prevents excess sodium excretion and maintains normal sodium levels 1
• Fludrocortisone (a synthetic mineralocorticoid) and hydrocortisone are both used to treat cerebral salt wasting and prevent hyponatremia 1
• Guidelines recommend hydrocortisone to prevent natriuresis in subarachnoid hemorrhage patients (Class I evidence) 1

Potential Adverse Effects

• Excessive mineralocorticoid effect from hydrocortisone can lead to hypokalemia requiring potassium supplementation 1
• Hydrocortisone may cause hyperglycemia, especially in diabetic patients 1
• Some patients may experience sodium and water retention, potentially leading to edema or hypertension 1

Special Considerations

• Certain medications and foods can interact with hydrocortisone, affecting its metabolism and potentially its effect on sodium levels 1:
  • Antiepileptics, barbiturates, and antituberculosis drugs may increase hydrocortisone requirements
  • Grapefruit juice and licorice may potentiate hydrocortisone's mineralocorticoid effects
• In patients with adrenal insufficiency, sodium intake should not be restricted, and potassium-containing salt substitutes should be avoided 1

In conclusion, hydrocortisone injections typically increase rather than decrease serum sodium levels through their mineralocorticoid effects on renal sodium reabsorption and water balance 1, 2.