Short answer: Yes. The prednisone label lists high blood sugar, new or unmasked diabetes, and higher needs for insulin or diabetes pills among its side effects, and says diabetes medicine doses may need adjusting. Insulin labels list corticosteroids among the medicines that weaken insulin. In one hospital review, 64% of patients on high-dose steroids who had glucose checked had at least one reading of 200 mg/dL or higher.
Prednisone is a corticosteroid (glucocorticoid). The prednisone tablet label lists, among endocrine side effects, decreased carbohydrate and glucose tolerance, diabetes (new onset or showing up when it was hidden before), sugar in the urine, high blood sugar, and increased requirements for insulin or oral diabetes medicines in people with diabetes. Under drug interactions it says that because corticosteroids may increase blood glucose, doses of diabetes medicines may need adjusting. It also says the higher risk of diabetes, fluid retention and high blood pressure should be considered in older people on corticosteroids.
The Humalog and Lantus labels list corticosteroids among drugs that may decrease the blood sugar lowering effect of insulin, along with diuretics, estrogens, oral contraceptives and some others. The Humalog label says dose adjustment and more frequent glucose monitoring may be needed when insulin is taken with these drugs.
| Study | What it looked at | Finding |
|---|---|---|
| Donihi 2006 | One-month chart review of 617 general medicine inpatients; 66 got 40 mg a day of prednisone or more (or the equivalent) for at least 2 days | 32 of the 50 who had glucose checked (64%) had at least one reading of 200 mg/dL or higher; 19 of 34 without known diabetes (56%) did too |
| Clore and Thurby-Hay 2009 | Review of studies published from 1950 to 2009 | Odds of new diabetes on glucocorticoids about 1.5 to 2.5 times higher; total dose and length of treatment were strong predictors, along with age and body mass index |
The hospital review covered high doses in people who were already ill, so it does not show how often a short, low-dose course raises blood sugar at home. The Clore review also argues that relying on fasting glucose alone can miss steroid-related high blood sugar, which is one reason it goes untreated.
The labels describe two things: blood sugar may run higher while a steroid is taken, and doses of insulin or diabetes pills may need to change. They do not give a set dose change, because it depends on the steroid, its dose and timing, and the person. That plan comes from the prescriber, including what happens to the insulin dose when the steroid course ends.
People without diagnosed diabetes can also develop high blood sugar on steroids, as the hospital review found. Symptoms such as unusual thirst or passing more urine are worth mentioning to whoever prescribed the steroid.
A steroid course is often short and prescribed by a different clinician than the one who manages diabetes. Dose Track can log the steroid next to insulin doses and glucose readings, so the start and end dates are clear when readings are reviewed.
Read more on Dose Track: Blood sugar · Insulin resistance · Humalog side effects · HbA1c