This information sheet should be read with the factsheet “Oral Corticosteroids (prednisolone and dexamethasone)”.

What effect can prednisolone and dexamethasone have on blood sugar levels?

Corticosteroid medicines such as prednisolone and dexamethasone (commonly called steroids) can change how your body handles carbohydrates and sugars (also known as glucose). They can raise your blood sugar level by blocking the action of your insulin. This means less sugar is able to move out of the bloodstream into muscles and other cells of the body. It also causes the liver to release extra sugar into the blood stream.

What is Steroid Induced Diabetes?

If your blood sugar level increases when taking steroids and you do not already have diabetes this is called “Steroid Induced Diabetes”.

Anyone taking corticosteroids can develop steroid induced diabetes. However the following factors increase a person’s risk:

Risk factors:

  • Taking high doses of prednisolone (7.5 mg daily or higher)
  • Taking high doses of dexamethasone (0.75mg daily or higher)
  • Being overweight
  • Being over 50 years of age
  • Family history of diabetes
  • History of gestational diabetes
  • Kidney impairment

Symptoms to look out for:

  • Increased thirst
  • Passing more urine
  • Feeling tired all the time
  • Headaches

However many people don’t get symptoms. Taking oral corticosteroids can also have side effects such as increased hunger, weight gain, blurred vision and mood swings, which can also be symptoms of diabetes.

How is Steroid Induced Diabetes managed?


Nursing staff will check your blood sugar level. If your blood sugar level is above normal, your doctor will review your sugar levels and discuss what medical treatment is needed. You will also be referred to the Eye and Ear diabetes clinical nurse educator.


Make sure you ask a nurse to check your blood sugar level when you come to your eye or your ear appointment.


It’s important to see your local doctor weekly to have your blood sugar level checked – even if you don’t have symptoms. This involves a simple finger-prick test. The best time to see your local doctor is in the afternoon (2 hours after lunch or late afternoon). Depending on your blood sugar level result, your local doctor will decide on an appropriate management plan.


If your blood sugar levels are regularly over 12.0 you may need insulin. This involves giving yourself 1-2 insulin injections each day. This is because oral medications are generally less effective in managing high blood sugar levels when it comes to steroids. Your health care team will discuss with you the best treatment options.

Will I always have steroid induced diabetes?

  • Most people (but not all) find their blood sugar levels return to normal when they stop taking their steroid medication.
  • Most people are able to stop using insulin (if they needed it).
  • If you need steroid medication in the future, it is important to monitor your blood sugar levels again and treat high sugars.
  • Some people may go onto develop diabetes even after stopping their steroid medication. See your GP every year to have a diabetes test.

What if I already have diabetes and need to take oral corticosteroids?

Taking oral corticosteroid when you already have diabetes is likely to increase your blood sugar levels.

How do I manage my diabetes while on oral corticosteroids?

Type 1 diabetes:

  • You will most likely need to increase your rapid acting insulin and long acting insulin doses.
  • If you are on an insulin pump, you will most likely need to increase your basal rate and bolus doses.

Type 2 diabetes:

  • You may need to go onto insulin injections while you are taking steroids.
  • If you are already on insulin you will most likely need to increase your insulin doses. Depending on which insulin you take, you may need to change to a different insulin while taking an oral corticosteroid.

Whether you have Type 1 or Type 2 diabetes it is important to have regular contact with your endocrinologist, diabetes educator and local doctor. Your Eye and Ear doctor may also refer you to the Eye and Ear Diabetes and Endocrinology clinic for short term management.

How high will my blood sugar levels get?

It varies from person to person. It can be common to see blood sugar levels between 13 to 20+ mmol/L. Some people’s blood sugar level can rise so high it reads as ‘Hi’ on the blood sugar machine.

A common pattern of sugar levels with diabetes if you are taking steroids is:

  • Normal blood sugar level in the morning when you first get up.
  • Blood sugar levels starts to rise by mid-morning to lunch. Between mid-afternoon to early evening blood sugar levels are at their highest levels.
  • Blood sugar levels then start to drop by 10pm-11pm and you wake up with a normal blood sugar level in the morning.
  • However, blood sugar levels remain high overnight and in the morning in some patients.

When should I monitor my blood sugar levels?

It is important to check and monitor your blood sugar levels frequently when taking an oral corticosteroid. Good times to check your blood sugars are:

  • Before each meal
  • Before bed (every second night)

Make sure you record your blood sugar levels. This information is important for your medical team in order to make changes to your diabetes management if needed.

As your steroid dose is reduced, your insulin doses also need to reduce at the same time to prevent hypoglycaemia (low blood sugar/hypos).


Disclaimer This document describes the generally accepted practice at the time of publication only. It is only a summary of clinical knowledge regarding this area. The Royal Victorian Eye and Ear Hospital makes no warranty, express or implied, that the information contained in this document is comprehensive. They accept no responsibility for any consequence arising from inappropriate application of this information.

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  • Oral corticosteroids and your blood sugar levels #9
  • Owner: Diabetes Education
  • Last Reviewed: April 7, 2020
  • Next Review: April 7, 2024