Can corticosteroid (cortisone) injections increase blood glucose levels, especially in patients with diabetes?

Can Cortisone Shots Increase Blood Sugars?

Yes, cortisone (corticosteroid) injections absolutely increase blood glucose levels, causing hyperglycemia in 56-86% of patients with and without pre-existing diabetes, and if left untreated, this increases mortality and morbidity risk including infections and cardiovascular events. 1

Mechanism and Clinical Impact

Corticosteroids elevate blood glucose through multiple pathways: they impair pancreatic beta cell insulin secretion, increase total body insulin resistance, and enhance hepatic gluconeogenesis 2. This is not a minor effect—the FDA drug label explicitly warns that "corticosteroids may increase blood glucose concentrations" and requires dosage adjustments of antidiabetic agents 3.

Magnitude and Timing of Blood Glucose Elevation

The degree of hyperglycemia directly correlates with the corticosteroid dose—higher doses cause more significant elevations 2, 4. Research demonstrates:

• Patients with well-controlled diabetes (HbA1c <7%) experienced an average rise of 38 mg/dL after injection 5
• Poorly controlled diabetic patients (HbA1c ≥7%) had an average increase of 98 mg/dL 5
• Insulin-dependent diabetics showed even larger increases averaging 99 mg/dL versus 50 mg/dL in non-insulin-dependent patients 5
• Peak glucose values can reach as high as 500 mg/dL in some cases 6

Critical Timing Pattern

For oral intermediate-acting steroids like prednisone taken in the morning:

• Peak hyperglycemia occurs approximately 8 hours after dosing (late morning/afternoon) 2
• The hyperglycemic effect is most pronounced during the day and often normalizes overnight even without treatment 1, 2
• After injection, hyperglycemia typically occurs within 24-72 hours and can persist for up to 7-10 days 5, 6

Location-Specific Effects

Important caveat: Injection site matters. Research shows:

• Knee injections caused significant fasting blood glucose elevations on days 1-2 post-injection 7
• Upper extremity injections (shoulder, wrist, hand) showed no significant blood glucose elevations 7
• This suggests larger joint spaces or higher systemic absorption from certain sites may produce more pronounced effects

Monitoring Recommendations

All diabetic patients receiving corticosteroid injections should:

• Monitor blood glucose four times daily (fasting and 2 hours after each meal) for at least 7-10 days post-injection 4, 5
• The most important reading is 2 hours after lunch (around 2-3 PM), which captures the peak steroid effect 4
• Target range should be 100-180 mg/dL (5.6-10.0 mmol/L) 1, 4

Critical warning signs requiring immediate medical attention:

• Glucose persistently >360 mg/dL (>20 mmol/L) or meter reading "HI"—indicates risk for hyperosmolar hyperglycemic state 4
• Glucose >270 mg/dL (>15 mmol/L) with ketones >2 mmol/L—signals diabetic ketoacidosis risk 4

Management Adjustments

For patients with pre-existing diabetes on oral medications or insulin, anticipate the need to increase antidiabetic therapy 3. The American Diabetes Association guidelines specify that for higher-dose glucocorticoids, insulin doses may need to increase by 40-60% or more 1, 4.

Common Pitfall to Avoid

Do not rely solely on fasting glucose measurements—this will miss the peak hyperglycemic effect that occurs in the afternoon and lead to undertreatment 4. Many patients have normal fasting glucose but significant afternoon/evening hyperglycemia 1.

Patient Counseling Points

Before administering corticosteroid injections to diabetic patients:

• Warn them explicitly that blood glucose will likely rise for several days 6
• Instruct them to monitor glucose regularly for up to one week after injection 6
• Patients with higher baseline HbA1c should monitor more closely as they experience greater glucose elevations 7
• Provide clear thresholds for seeking urgent medical care if glucose exceeds safe limits 4

Special Consideration for Non-Diabetic Patients

Even patients without known diabetes can develop steroid-induced hyperglycemia 1. Consider baseline glucose screening before corticosteroid administration, particularly in patients with risk factors for diabetes 8.