Steroids and High Blood Sugar: Why Does It Happen and What Should I Watch For?

Yes. Steroid medicines (corticosteroids), such as prednisolone and prednisone, can raise blood sugar. The NHS lists high blood sugar or diabetes among the possible serious side effects of steroids, and says the risk is higher with high doses or longer treatment. This is often called steroid-induced hyperglycaemia.

This guide is for adults who have a high glucose reading while taking, or soon after taking, a steroid. It explains what the link means, what monitoring is usually discussed and what to ask. It cannot tell you whether you have diabetes or how your treatment should change.

The NHS advises calling emergency services or going to an emergency department if high blood sugar comes with any of the signs below. Do not drive yourself, and take your medicines with you if you can.

These signs can point to diabetic ketoacidosis, which the NHS describes as life-threatening. Do not wait for a routine appointment or an online reply if they appear.

• Feeling or being sick, or stomach pain.
• Fast breathing or a racing heartbeat.
• Drowsiness or difficulty staying awake.
• Breath that smells fruity.
• Confusion or difficulty concentrating.
• High ketone levels in a blood or urine test, if you have been told to check ketones.

The NHS lists strong thirst, needing to pee more often, tiredness or weakness, blurred vision and weight loss as symptoms of high blood sugar. MedlinePlus adds dry mouth and dry skin, and notes frequent urination may happen at night.

Symptoms often develop gradually, and the NHS says they may not appear until levels are very high. So a person can feel well and still have a raised reading. That is one reason why monitoring is sometimes arranged rather than relying on how you feel.

The NHS advises contacting a GP or care team if you have symptoms of high blood sugar but have not been diagnosed with diabetes. MedlinePlus also advises contacting your provider if your blood sugar is too high and you do not understand why.

The NHS links serious steroid side effects, including high blood sugar, to higher doses and longer courses. People who already have diabetes may find their usual readings rise. The NHS prednisolone page says the medicine may not be suitable for everyone with diabetes, or with diabetes in the family, and that diabetes medicines may interact with it.

It is not only tablets. MedlinePlus asks people with diabetes whether they have recently had a glucocorticoid (steroid) injection into a joint or elsewhere when looking for reasons for a high reading. Tell your clinician about every steroid you have had, including injections.

Other things can raise blood sugar at the same time. The NHS lists being unwell or stressed, recent surgery, being less active than usual, eating more sugary or starchy food, and diabetes medicine that is not working well. Clinicians usually consider these alongside the steroid rather than assuming one cause.

If you notice high readings, the safest first step is to contact the prescriber or care team, not to stop the steroid. The NHS says do not stop taking a steroid without talking to your doctor first, and that stopping some steroids suddenly can cause symptoms such as extreme tiredness, feeling sick, dizziness and joint pain. MedlinePlus gives the same advice for prednisone and explains that stopping suddenly may leave the body without enough of its own natural steroids.

The NHS prednisolone page adds that stopping suddenly can make the underlying condition worse, and that a doctor may reduce the dose gradually. Do not change the dose or timing of a steroid, or of any diabetes medicine, without advice from the prescriber. Decisions about the steroid and about blood sugar treatment are made together by the team.

MedlinePlus says the doctor will order lab tests to check the body's response to prednisone, and that the dose may be changed often during treatment. Depending on the person, the team may suggest finger-prick checks at home, a blood glucose test or an HbA1c test. Ask which test they want, when and how often.

The NHS describes HbA1c as a measure of average blood sugar over about the last 2 to 3 months, and fasting or home glucose tests as snapshots at a point in time. Because these tests cover different time periods, results during a recent steroid course may not line up. The guide on A1C and glucose results that do not match explains this in more detail.

As a general guide for people with diabetes, the NHS describes a fasting or before-meal reading above 7 mmol/L, a reading 90 minutes or more after eating above 11 mmol/L, or an HbA1c of 48 mmol/mol (6.5%) or above as high. The NHS notes targets differ by person, and labs and meters may report results differently. Check your own targets with your care team rather than using these figures to diagnose yourself.

Sometimes a urine test shows glucose. That finding has several possible causes, which the guide on glucose in urine covers.

The NHS sources used here do not say how often or how quickly steroid-related high blood sugar settles after a course ends, so no general answer is given in this guide. What happens can depend on the person, any existing diabetes, the dose and the length of treatment.

Ask your clinician whether follow-up testing is planned after the steroid is reduced or finished, who will arrange it and what result would need a further conversation. Keep a note of the dates you started and changed steroid treatment next to any glucose results, as this makes later results easier to interpret.

Bring a list of all your medicines, including steroid injections, inhalers, creams and anything bought without a prescription, plus your recent glucose readings with dates and times.

• Is my steroid likely to be affecting my blood sugar, and what else could be contributing?
• Which test do you want me to have, and how often: home checks, a blood glucose test or HbA1c?
• What reading or symptom means I should call you, and what means I should get emergency care?
• If I already have diabetes, who will review my diabetes treatment while I am on steroids?
• Will my blood sugar be checked again after the steroid dose is reduced or stopped?
• Is it safe to keep taking my steroid as prescribed while we sort this out?

On SameCase, patients and verified doctors share de-identified cases. Reading how others described a glucose rise during steroid treatment, and which questions their clinicians answered, can help you write a clearer list for your own appointment. Similar cases cannot diagnose you or predict your results, and they never replace advice from the team prescribing your treatment.