Nursing care
Why corticosteroids raise blood glucose, and when to check it
Written and reviewed by Dana Whitfield, RN, MSN · 4 min read · Updated October 2026
Short answer
Glucocorticoids such as prednisone push the liver to make more glucose, make muscle and fat respond less to insulin, and reduce insulin release from the pancreas. Together these raise blood glucose, mostly after meals. With a morning dose, levels often peak in the afternoon and evening while fasting values look normal, so monitoring must include later-day checks.
Steroid drugs copy cortisol's job of raising glucose
Cortisol is a stress hormone, and one of its roles is to make sure fuel is available during illness or injury. Glucocorticoid medicines such as prednisone, prednisolone, methylprednisolone and dexamethasone act on the same receptors, usually at much higher strength than the body's own cortisol. Their anti-inflammatory benefit comes packaged with these metabolic effects.
Prescribing information lists decreased carbohydrate tolerance, the unmasking of previously unrecognised diabetes and increased insulin or oral agent requirements in people who already have diabetes. Higher doses, longer courses, older age, higher body weight and prior glucose intolerance all increase the likelihood. A client without known diabetes can therefore develop high readings for the first time while on steroids.
Three ways glucose rises: liver, muscle and pancreas
In the liver, glucocorticoids switch on enzymes that build new glucose, a process called gluconeogenesis, and encourage glycogen breakdown. More glucose is released into the blood even when the client has not eaten. In muscle, glucocorticoids interfere with the transporters that move glucose into cells after a meal, so glucose clears from the blood more slowly.
In fat tissue, glucocorticoids increase the breakdown of fat, raising free fatty acids that worsen insulin resistance further. At the same time, they reduce the pancreas's ability to release insulin in response to glucose. The combination of extra glucose supply, poorer uptake and less insulin explains why after-meal glucose is affected most noticeably.
Why the timing of the dose shapes the pattern
With a once-daily morning dose of an intermediate-acting steroid such as prednisone, glucose usually climbs over the following hours and is most raised in the afternoon and evening. By the next morning the effect has partly worn off, so a fasting reading can be normal even when the client has been significantly hyperglycaemic for most of the previous day.
That is why monitoring should not rely on fasting glucose alone. Pre-lunch, pre-dinner or after-meal checks are more likely to catch the peak. Longer-acting agents such as dexamethasone, or doses given more than once a day, produce a flatter and more prolonged rise, so the expected pattern depends on the actual drug and schedule ordered.
Monitoring, warning signs and the taper
Follow the facility's protocol for glucose monitoring when steroids start, including clients without diabetes. Report readings above the prescribed range, and watch for thirst, frequent urination, fatigue or blurred vision. In clients with diabetes, insulin requirements may rise substantially, often with doses timed to cover the afternoon peak, as decided by the prescriber.
The reverse matters as much. As the steroid dose is reduced or stopped, glucose falls and insulin or sulfonylurea doses need to come down with it, or hypoglycaemia can follow. Flag every steroid dose change to the prescriber managing glucose, and teach clients going home on a taper to keep checking glucose and report lows as well as highs.
Apply the pattern to a hypothetical scenario
A hypothetical client without diabetes is started on morning prednisone for a lung condition. On day two the fasting glucose is normal, but the 5 pm reading is well above the target range and the client is thirsty. Options include reassuring the client because the fasting value was normal, stopping the prednisone, ignoring it as stress, or reporting the reading and continuing scheduled checks.
Reporting is correct because the afternoon reading reflects the expected steroid peak and may need treatment. A normal fasting value does not exclude daytime hyperglycaemia. Stopping prednisone abruptly is unsafe and not a nursing decision, especially after prolonged use, because of adrenal suppression. Labelling the reading as stress misses the clear drug-timing link.
Sources and further reading
Europe PMC: Practical guide to glucocorticoid induced hyperglycaemia and diabetes (Diabetes Therapy, 2023). Hepatic gluconeogenesis, muscle glucose transporter effects, lipolysis, reduced beta-cell insulin release, risk factors, afternoon peak and reducing glucose-lowering doses during taper.
Europe PMC: Management of glucocorticoid-induced hyperglycemia (Diabetes Metab Syndr Obes, 2022). Postprandial hyperglycaemia from insulin resistance, late afternoon and evening peak with morning dosing, misleading fasting values, monitoring timing and insulin reduction on taper.
DailyMed: Prednisone tablets prescribing information. Decreased carbohydrate tolerance, latent diabetes, increased insulin requirements and gradual withdrawal to limit adrenal insufficiency.
The next step on this is the same as on everything else here: answer questions and read the rationales. Our pharmacology practice questions are the closest set to what this page covers.
One question from the pharmacology set
A client with heart failure is started on furosemide 40 mg PO daily. Which findings should the nurse report to the provider before administering the next dose? Select all that apply.
Rationale
Furosemide is a loop diuretic, so the two things you are watching are potassium and kidney function. A potassium of 2.9 mEq/L is below the 3.5–5.0 reference range and puts the client at risk for dysrhythmia — hold and report. Muscle cramps with palpitations are the clinical face of that same hypokalemia, so they are reported together, not separately. A creatinine that doubles signals the diuresis has outrun renal perfusion. A blood pressure of 132/78 and a 1 kg loss are the expected response to the drug working, not reasons to hold it.
Answer: A, D, E
Common questions
Why can fasting glucose be normal on prednisone?
A morning dose produces its biggest effect in the afternoon and evening, and much of it has faded overnight. Later-day checks give a truer picture.
Does steroid-induced hyperglycaemia go away?
It often improves as the dose is reduced or stopped, although steroids can unmask underlying diabetes that persists. Glucose-lowering doses must be reduced in step to avoid lows.
Should the nurse hold a steroid dose because glucose is high?
No. Report the reading and follow the glucose protocol. Holding or stopping a steroid is a prescriber decision, and stopping abruptly after long use risks adrenal insufficiency.
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