How to Lower Blood Sugar After a Cortisone Injection

Cortisone injections reliably raise blood sugar, and the spike usually peaks within the first day or two before fading on its own. For people with diabetes, the practical strategy combines more frequent glucose monitoring, short-term adjustments to existing medications (often increasing insulin doses), staying hydrated, and being physically active when comfortable. The size and duration of the spike depend heavily on how well your blood sugar was controlled before the shot, which steroid was used, and whether you take insulin. Understanding the timeline and your personal risk factors puts you in the best position to ride out the disruption safely.

How Long the Blood Sugar Spike Actually Lasts

The spike is real but temporary. In a study of diabetic patients receiving steroid injections for musculoskeletal pain, fasting blood glucose was significantly elevated on day one after the injection but had already returned to baseline by day two.¹ A separate study tracking daily fasting glucose in diabetic patients after hand and wrist corticosteroid injections found statistically significant elevations on day one and day two, a smaller and non-significant bump on day three, and no meaningful difference from baseline on days four through seven.²

The first 24 to 48 hours are the danger zone. That is when your readings will look the worst and when you need to be most vigilant. By the third day, most people’s glucose is drifting back toward normal, and by the end of the first week, the injection’s effect on blood sugar has essentially washed out. A clinical review of ten studies on local musculoskeletal steroid injections in diabetic patients found that while peak individual readings could climb as high as 518 mg/dL, glucose generally returned to baseline anywhere from less than 24 hours to about 10 days, with most cases resolving within the first several days.³

Who Gets Hit the Hardest

Not everyone experiences the same degree of blood sugar disruption. The single biggest predictor is how well-controlled your diabetes is before you get the shot. Patients with an HbA1c above 7% saw significantly larger glucose spikes on day one compared to those whose HbA1c was at or below 7%.¹ In concrete terms, one study measured an average increase of about 64 mg/dL above baseline at the one-day mark, but patients with higher HbA1c experienced larger jumps than that average.¹

Patients already on insulin also tend to see a bigger rise than those managing diabetes with oral medications alone. This probably reflects the fact that insulin-dependent patients have less reserve pancreatic function to compensate when steroids push glucose production up. The clinical review that compiled results across ten studies found mean blood sugar elevations ranging from 125 to 320 mg/dL, a wide spread that underscores how individual the response can be.³

People without a diabetes diagnosis are not immune. Steroid treatment can push glucose high enough in previously healthy people to meet the threshold for what clinicians call steroid-induced diabetes, a temporary state that resolves once the drug clears but still needs management while it lasts.⁴ If you have prediabetes or a family history of diabetes, your risk of a noticeable spike is higher than someone with completely normal glucose metabolism.

Practical Steps You Can Take on Your Own

The non-medication strategies for bringing blood sugar down after a cortisone injection are the same ones that work any time glucose is running high, but applying them deliberately during the 48-hour spike window makes a real difference.

Monitor more often: Check your blood sugar at least four times a day for the first two to three days after the injection, including before meals and at bedtime. If you use a continuous glucose monitor, pay close attention to the trend arrows and alerts during this period. Researchers who studied blood glucose changes after steroid injection specifically recommended careful monitoring on the first day for patients with poorly controlled diabetes.¹
Stay hydrated: When blood sugar runs high, your kidneys try to flush the excess glucose through urine, which can dehydrate you. Drinking plenty of water helps your kidneys do their job and prevents dehydration from compounding the problem.
Cut back on refined carbohydrates: For the first two to three days, reducing your intake of white bread, sugary drinks, rice, and other fast-digesting carbs gives your body less glucose to deal with on top of what the steroid is already producing. This is not the time for a cheat meal.
Move your body if you can: Physical activity pulls glucose out of the bloodstream and into working muscles. Even a 15- to 20-minute walk after meals can meaningfully blunt a post-meal spike. The caveat is that you just had an injection for pain, so listen to your body and avoid loading the joint that was treated. Upper-body injection? Go for a walk. Knee injection? Try some seated arm exercises or gentle cycling if it does not aggravate the joint.

None of these steps will fully cancel the steroid’s effect on glucose. They chip away at the spike from the edges, and together they can keep your readings in a safer range while the drug clears your system.

When You Need a Medication Adjustment

If your blood sugar runs very high despite lifestyle measures, a temporary change to your medication regimen is often necessary. This is a conversation to have with your prescribing doctor or endocrinologist before the injection whenever possible, because having a plan in place beats scrambling when your meter reads 350.

For people who take insulin, the most common approach is a short-term dose increase. Corticosteroids tend to drive blood sugar up most during the afternoon and evening, because most injected steroids peak in the hours after administration and their glucose-raising effect builds over the day. Hospital protocols for steroid-induced hyperglycemia often involve increasing the mealtime insulin given at lunch and dinner to match this pattern, rather than simply raising the morning basal dose.⁵ This approach makes sense because a blanket increase to your basal insulin could cause low blood sugar overnight or in the morning, when the steroid’s glucose-raising push has waned.

For people who manage diabetes without insulin, other medications have been studied with varying success. A review of the available evidence found that DPP-4 inhibitors, metformin, and intermediate-acting insulin (NPH) all showed reasonable safety and effectiveness for steroid-induced blood sugar elevations.⁶ NPH insulin is particularly well-suited because its duration of action roughly matches the glucose pattern caused by a single morning steroid dose. Your doctor might prescribe a small dose of NPH to cover the afternoon spike, to be used only for the first day or two after the injection.

The key point is that any medication change should be temporary. Once the steroid clears and your blood sugar normalizes, you go back to your usual regimen. If you increase insulin on your own without clear guidance from your provider, you risk hypoglycemia as the steroid wears off, which can be just as dangerous as the high blood sugar you are trying to fix.

The Steroid Itself Matters

Not all corticosteroids are created equal when it comes to blood sugar disruption. The type of steroid your doctor injects, and even the formulation, can affect how much your glucose spikes.

Among systemic (oral or intravenous) corticosteroids, dexamethasone and methylprednisolone tend to cause more hyperglycemia than prednisolone or hydrocortisone. A study comparing different corticosteroids in hospitalized patients found that dexamethasone raised average blood glucose by about 17 mg/dL more than hydrocortisone and about 20 mg/dL more than prednisolone over a week. Methylprednisolone was even worse, running roughly 24 mg/dL higher than hydrocortisone and 27 mg/dL higher than prednisolone.⁷ These differences reflect how potent each steroid is at suppressing insulin’s action and how long it stays active in your body.

For local injections into joints, the formulation can also make a difference. Extended-release triamcinolone acetonide, a newer formulation designed to release the steroid slowly within the joint, caused roughly half the blood sugar disruption of the standard crystalline triamcinolone formulation in a trial of patients with knee osteoarthritis and type 2 diabetes. Patients who received the extended-release version spent about 63% of the first three days within the target glucose range of 70 to 180 mg/dL, compared to about 50% for those who received the standard version.⁸ The extended-release formulation keeps more of the steroid inside the joint rather than letting it leak into the bloodstream, which is exactly why it causes less systemic havoc.

If you have diabetes and your doctor is recommending a cortisone injection, it is worth asking which steroid and which formulation they plan to use. You may not always have a choice, since the decision also depends on which drug works best for your specific joint or tendon problem. But when the clinical options are equivalent, a formulation that stays local rather than flooding your bloodstream is a clear win for glucose control.

What to Talk to Your Doctor About Before the Injection

The best time to manage a post-injection blood sugar spike is before it happens. If you have diabetes, a conversation with both your treating orthopedic or pain specialist and your diabetes care provider sets you up with a plan rather than a crisis.

A few things to discuss:

Your current HbA1c: Since higher HbA1c strongly predicts a bigger spike, knowing your recent level helps everyone gauge the risk.¹ If your HbA1c is above 7%, you and your doctor should be prepared for a larger glucose excursion.
A specific sliding scale or dose adjustment: Ask your endocrinologist or primary care provider for written instructions on how to adjust your insulin or oral medications for the two to three days after the injection. Having concrete numbers (e.g., “increase your lunchtime rapid-acting insulin by 20% on days one and two”) is better than vague advice to “keep an eye on it.”
A threshold for calling: Agree on a blood sugar level or pattern that should trigger a call to your doctor. For most people, a sustained reading above 300 mg/dL or any symptoms of diabetic ketoacidosis (nausea, vomiting, fruity breath, confusion) should prompt urgent contact.
Whether an alternative exists: In some cases, particularly for patients whose diabetes is already difficult to control, your doctor may consider alternative approaches that do not use corticosteroids at all. These might include physical therapy, hyaluronic acid injections for osteoarthritis, or other non-steroidal options. The trade-off is that steroids are often the fastest and most effective way to reduce joint or soft-tissue inflammation, so the decision depends on how severe your pain is relative to your glucose control challenges.

Joint British Diabetes Societies guidelines explicitly state that steroid use in people with pre-existing diabetes will worsen glucose control and warrants temporary additional glycemic management.⁴ The word “temporary” is important. This is not a sign that your diabetes management is failing. It is a predictable pharmacological side effect, and it passes.

If You Do Not Have Diabetes

People without diabetes sometimes assume the blood sugar warnings do not apply to them. In most cases, a healthy pancreas can compensate for the steroid’s glucose-raising effect by producing more insulin. You might run a bit higher than normal for a day or two, but your body handles it without you ever noticing.

The exceptions are people who are on the edge. If you carry excess weight, have a family history of type 2 diabetes, or have been told you have prediabetes or insulin resistance, a cortisone injection can temporarily push your glucose into diabetic territory. The Joint British Diabetes Societies notes that a rise in glucose may occur in people without a known diabetes diagnosis, a state they term steroid-induced diabetes.⁴ This resolves once the steroid clears, but it is worth knowing about because symptoms of high blood sugar (excessive thirst, frequent urination, blurry vision, fatigue) can be alarming if you do not expect them.

If you fall into a higher-risk category, it is reasonable to ask your doctor about checking a fasting blood glucose or HbA1c before the injection. If the results come back in the prediabetic range, that information changes how aggressively you should monitor after the shot, and it is also valuable health information in its own right.

Why Steroids Raise Blood Sugar in the First Place

Corticosteroids mimic cortisol, your body’s own stress hormone. Cortisol’s job during stress is to make sure your brain and muscles have plenty of fuel, and it does this partly by telling the liver to dump stored glucose into the bloodstream and partly by making your muscle and fat cells less responsive to insulin. When you inject a concentrated dose of synthetic cortisol into a joint, some of it inevitably leaks into the general circulation and triggers those same pathways. The liver starts producing more glucose than you need, and your tissues become temporarily resistant to the insulin that would normally clear it away. The result is a predictable rise in blood sugar that tracks the steroid’s absorption and clearance.

The good news embedded in this mechanism is that the spike is self-limiting. Once the drug is metabolized and cleared, your liver goes back to normal glucose output, your cells regain their insulin sensitivity, and blood sugar settles. Local injections into joints cause smaller and shorter spikes than oral steroid courses precisely because less drug reaches the bloodstream. The extended-release formulations mentioned earlier take this logic further, engineering the drug to stay in the joint space and minimize the systemic leak that drives the glucose problem.

Physical Activity and the Steroid Effect

Exercise is one of the most effective non-drug tools for lowering blood sugar, but there is a wrinkle when corticosteroids are involved. A study examining prednisolone’s effect on exercise performance found that blood glucose remained elevated above placebo levels immediately after exercise and for up to two hours afterward, even though exercise normally lowers glucose. It took about three hours after exercise for glucose in the steroid group to drop to the same level as the placebo group.⁹

This does not mean exercise is useless when you are dealing with a steroid spike. It means the glucose-lowering effect takes longer to show up and may be partially blunted while the steroid is at its peak. Walking after lunch still helps. A gentle bike ride still helps. Just do not expect your post-exercise glucose check to drop as dramatically as it normally would. The benefit is real, but it is competing against the steroid’s glucose-raising push, so the net effect is smaller than what you are used to seeing. As the steroid clears over the following days, exercise’s glucose-lowering effect returns to full strength.

For people who have just had a joint injection and are in pain, the exercise options may be limited. Focus on what you can do rather than what you cannot. Even non-weight-bearing movements that use large muscle groups, such as seated leg extensions, arm cycling, or swimming (once the injection site is healed), can help your muscles pull glucose from the blood.