Steroid-Induced Hyperglycemia Insulin Calculator
Estimate a starting intermediate-acting (NPH) insulin dose for high blood glucose caused by glucocorticoid (steroid) treatment, from body weight and steroid dose.
How to Use This Calculator
- Enter body weight in kilograms.
- Select the glucocorticoid — prednisone, methylprednisolone, dexamethasone or hydrocortisone. The tool converts it to a prednisone-equivalent.
- Enter the daily steroid dose in mg/day.
- Read the result: a starting NPH insulin estimate, the prednisone-equivalent dose, and the weight-based dosing factor.
Give the NPH with the morning steroid so their peaks overlap, titrate to glucose readings, and reduce the insulin as the steroid is tapered. This is an educational reference for clinicians and students, not a home-dosing tool.
Why Steroids Raise Blood Glucose
Glucocorticoids such as prednisone and dexamethasone increase insulin resistance and the liver's glucose output, producing a characteristic afternoon-and-evening rise in blood glucose when given once each morning. Because the pattern mirrors the steroid's action, intermediate-acting NPH insulin — given with the morning steroid — is a common, well-matched treatment.
The dosing factor rises with the steroid dose, from about 0.1 u/kg at 10 mg of prednisone-equivalent up to a cap of 0.4 u/kg at 40 mg or more.
Worked example: 80 kg patient on 40 mg prednisone → factor = min(0.4, 0.4) = 0.4 → 80 × 0.4 = 32 units NPH with the morning steroid.
Glucocorticoid Equivalent Doses
| Steroid | Dose equal to 5 mg prednisone |
|---|---|
| Prednisone / Prednisolone | 5 mg |
| Methylprednisolone | 4 mg |
| Dexamethasone | 0.75 mg |
| Hydrocortisone | 20 mg |
Long-acting steroids such as dexamethasone cause a flatter, 24-hour glucose rise, so a basal insulin may suit them better than NPH — a clinical judgement for the care team.
Monitoring Glucose During Steroid Treatment
Because once-daily morning steroids push glucose up later in the day, the rise is easiest to miss on a fasting morning check. The most informative readings are before lunch, before dinner, and at bedtime, when the afternoon-to-evening peak shows up.
Who is most at risk
Anyone on moderate-to-high steroid doses can be affected, but the risk is highest with pre-existing diabetes or prediabetes, obesity, a family history of type 2 diabetes, and higher or longer steroid courses. People without diabetes can still develop steroid-induced hyperglycemia, so new glucose checks are worthwhile when starting treatment.
Typical glucose targets
For most hospitalized patients, guidelines aim for roughly 140–180 mg/dL (7.8–10.0 mmol/L), avoiding both persistent highs and hypoglycemia. Targets are individualized by the care team — frailer or end-of-life patients are often managed more loosely.
Frequently Asked Questions
How much insulin is needed for steroid-induced hyperglycemia?
A common inpatient starting point is weight-based NPH given with the morning steroid: roughly 0.1 units/kg for every 10 mg of prednisone-equivalent, capped near 0.4 units/kg at 40 mg or more. An 80 kg person on 40 mg prednisone might start around 32 units. The dose is then titrated to glucose.
Why is NPH insulin used for steroid hyperglycemia?
Once-daily morning prednisone causes glucose to climb through the afternoon and evening, then settle overnight. NPH peaks at 4–10 hours, so a morning NPH dose matches that pattern well and tends to fade overnight, lowering the risk of nocturnal lows.
What happens to the insulin dose when steroids are tapered?
The insulin must come down with the steroid. As the glucocorticoid dose drops, insulin resistance falls, and keeping the old insulin dose can cause dangerous hypoglycemia. The care team reduces insulin in step with the steroid taper and often stops it when the steroid stops.
Can I use this calculator at home?
No. Starting or changing insulin for steroid hyperglycemia requires a prescriber, glucose monitoring, and a plan for the steroid taper. This tool is an educational reference for clinicians and students, not a home-dosing aid.
When is the best time to check blood sugar while on steroids?
With once-daily morning steroids, glucose tends to climb through the afternoon and evening, so before-dinner and bedtime checks reveal the rise best. A fasting morning reading can look near-normal and miss it. Checking before lunch, before dinner and at bedtime gives the clearest picture.
Does steroid-induced high blood sugar go away after stopping steroids?
Often yes — glucose usually improves within days as the steroid is tapered and insulin resistance falls, and insulin is reduced or stopped alongside it. In some people, especially those with risk factors, steroids unmask lasting type 2 diabetes, so follow-up glucose or A1c testing afterward is advised.
Sources
- Clore JN, Thurby-Hay L. "Glucocorticoid-induced hyperglycemia." Endocr Pract. 2009.
- American Diabetes Association. Standards of Care in Diabetes — 2024. Section 16 (Diabetes Care in the Hospital).
Last reviewed: June 2025