Does Hydrocortisone Injection Significantly Increase Blood Glucose?
Yes, hydrocortisone injection does significantly increase blood glucose levels, though the magnitude is generally less than with dexamethasone or methylprednisolone, and the route of administration (oral versus intravenous) does not significantly affect the degree of hyperglycemia. 1, 2
Magnitude and Pattern of Hyperglycemia
Hydrocortisone causes clinically significant hyperglycemia, particularly in the afternoon and evening hours, with peak effects occurring 4-6 hours after administration. 1, 3
The FDA label for hydrocortisone explicitly lists "decreased carbohydrate and glucose tolerance, glycosuria, and increased requirements for insulin or oral hypoglycemic agents in diabetes" as endocrine adverse reactions. 2
When comparing different corticosteroids, dexamethasone causes 16.6 mg/dL (0.92 mmol/L) greater mean blood glucose elevation than hydrocortisone, and methylprednisolone causes 23.9 mg/dL (1.33 mmol/L) greater elevation than hydrocortisone across 7 days of treatment. 4
The hyperglycemic effect is most pronounced during daytime hours and often normalizes overnight, even without treatment. 3
Route of Administration: Oral vs Intravenous
The route of hydrocortisone administration (oral versus intravenous) does not significantly affect blood glucose levels. 5
A 2024 study of 384 adult inpatients found no significant difference in mean glucose concentrations between oral and intravenous hydrocortisone on day 1 (mean difference 0.17 mmol/L, p=0.827) or across all 7 days (mean difference 0.20 mmol/L, p=0.639). 5
However, continuous intravenous infusion of hydrocortisone results in fewer hyperglycemic episodes compared to bolus administration (10.5 vs 15.7 episodes per patient, p=0.039), making tight glycemic control easier to achieve. 6
Site-Specific Injection Considerations
Local corticosteroid injections in the upper extremity (hand, wrist, shoulder) do not cause significant blood glucose elevations, while knee injections do cause measurable increases. 7, 8
Patients receiving hand/wrist injections with 1 mL triamcinolone experienced only slight, clinically insignificant increases in blood glucose (average increase 14.2 mg/dL on day 1). 8
Knee injections caused significant fasting blood glucose elevations on postinjection days 1 and 2. 7
Preinjection hemoglobin A1c was the most significant predictor of post-injection hyperglycemia, not the corticosteroid dose or number of injections. 7
Monitoring Recommendations
Capillary glucose monitoring is strongly recommended for all patients receiving hydrocortisone, regardless of route of administration. 5
Monitor blood glucose four times daily (fasting and 2 hours after each meal), with particular attention to afternoon and evening readings when steroid effects peak. 3
Target blood glucose range should be 5-10 mmol/L (90-180 mg/dL) for hospitalized patients. 3
Do NOT rely on fasting glucose alone—this will miss the peak hyperglycemic effect and underestimate severity. 3
Management Strategy
For patients developing significant hyperglycemia on hydrocortisone, initiate NPH insulin at 0.3-0.5 units/kg/day given in the morning to match the pharmacokinetic profile of the steroid. 1, 3
For patients without diabetes experiencing hyperglycemia, a single morning dose of NPH insulin may be appropriate. 1
For patients with pre-existing diabetes on insulin, add NPH insulin at 0.1-0.3 units/kg/day to their usual regimen, with doses adjusted according to steroid dose and oral intake. 1
Insulin requirements can decline rapidly after hydrocortisone is stopped—adjust doses accordingly to avoid hypoglycemia. 1, 3
Sulfonylureas are not recommended for managing steroid-induced hyperglycemia. 1
Critical Pitfalls to Avoid
Failing to anticipate the diurnal pattern: Hydrocortisone causes peak hyperglycemia in the afternoon/evening, not in the morning. 3
Monitoring only fasting glucose: This misses the peak effect and leads to undertreatment. 3
Not reducing insulin when tapering steroids: This causes hypoglycemia as steroid effects wear off. 1, 3
Assuming local injections are risk-free: While upper extremity injections pose minimal risk, patients with poor baseline glycemic control (higher HbA1c) should still monitor glucose more closely. 7