What Are the Side Effects of Steroid Injections for Dogs?

By Dr. Zubair Khalid, DVM, MS, PhD · 2026-08-14

Key Takeaways

• Injectable corticosteroids, such as methylprednisolone acetate, are anti-inflammatory drugs that mimic natural hormones and are administered for slow release over weeks, differing from oral steroid administration.
• Common, generally mild side effects include increased thirst, increased urination, and a larger appetite, typically resolving within one to three weeks, though increased appetite may persist longer.
• Serious adverse events requiring immediate emergency veterinary care include collapse, seizures, difficulty breathing, and facial or throat swelling, indicative of anaphylaxis, neurological compromise, or metabolic crisis.
• Potential serious complications include gastrointestinal ulceration, evidenced by severe vomiting or dark, bloody stool, and the exacerbation of underlying conditions like diabetes or kidney disease.
• Long-term or repeated steroid injections can lead to adrenal gland suppression, Cushing's syndrome, and worsening of joint damage if used for conditions like arthritis, necessitating careful risk-benefit assessment by a veterinarian.
• Owners must maintain a log of water intake, urination frequency, appetite, and energy levels, and avoid administering any other medications, including human over-the-counter drugs, without veterinary consultation due to potential drug interactions.

If your dog just received a steroid injection, you are probably watching closely for any change. Most dogs tolerate these injections well, and the side effects are usually mild and temporary. The most common effects are increased thirst, increased urination, and a bigger appetite, all of which typically fade within a few days to a couple of weeks. However, some side effects can be serious, and a few specific signs mean you should seek emergency care immediately. If your dog shows any of these signs, do not wait: collapse, seizures, difficulty breathing, or swelling of the face or throat. Go to the nearest emergency veterinary hospital right away.

Steroid injections are different from steroid pills. An injection releases medication slowly over weeks, so the effects last longer and the side effects can follow a different timeline. This article focuses on injectable corticosteroids, which are anti-inflammatory drugs that mimic hormones your dog's body makes naturally. The most common type given by injection is methylprednisolone acetate, often sold under the brand name Depo-Medrol. Another common type is a cortisone shot, which is a general term for any corticosteroid injection.

Is This an Emergency?

The table below sorts what you might see into three levels. Use it as a guide, not a diagnosis. When in doubt, call your veterinarian.

If you see any sign in the first column, do not call for advice. Go to an emergency clinic now. These signs can indicate a severe allergic reaction, a neurologic problem, or a metabolic crisis that requires immediate in-person treatment. Remote advice cannot help in these situations.

What Is Most Likely Going On

Your dog's body is adjusting to a strong anti-inflammatory drug. The injection suppresses inflammation by calming the immune system. It also affects how the body handles water, salt, and sugar. That is why the most common side effects are increased thirst and urination. Your dog may drink twice as much water as usual and need to go outside more often. This usually starts within a day or two and can last for one to three weeks, depending on the dose and the specific drug.

Increased appetite is also common. Your dog may act hungry all the time or beg for food more than usual. This effect can last as long as the injection is active. You can help by feeding normal portions and offering low-calorie treats like green beans or carrot slices. Do not increase the amount of food, because rapid weight gain is a possible side effect.

Mild lethargy or restlessness can happen in the first few days. Some dogs sleep more, while others pace or pant. These behaviors usually settle down on their own. Watch your dog's breathing rate at rest. Count breaths for 30 seconds and multiply by two. If the resting rate is above 40 breaths per minute, call your veterinarian.

What Else Could Be Going On

Some side effects look like other health problems. For example, increased thirst and urination can also be signs of diabetes or kidney disease. If your dog was already prone to these conditions, the steroid injection can make them more obvious. Your veterinarian may want to run blood or urine tests to check.

Steroid injections can also affect the stomach and intestines. Mild stomach upset is possible, but severe vomiting or bloody stool is not normal. These signs can indicate stomach ulcers, which are a known risk of corticosteroid use. Ulcers are painful and can be dangerous if they bleed. If you see dark, tarry stool or repeated vomiting, seek same-day care.

In rare cases, a dog can have an allergic reaction to the injection itself. This is different from the drug's normal effects. Allergic reactions usually happen within minutes to hours after the injection. Signs include facial swelling, hives, itching, or difficulty breathing. These require emergency treatment.

Long-Term Effects of Repeated Injections

One injection rarely causes permanent problems. The risks increase when injections are given repeatedly over months or years. Long-term use can suppress the adrenal glands, which produce natural steroids. This can make your dog unable to handle stress or illness. It can also lead to a condition called Cushing's syndrome, where the body has too much steroid activity. Signs include a pot-bellied appearance, thinning skin, hair loss, and increased susceptibility to infections.

Repeated injections can also worsen joint damage if used for arthritis. The drug reduces pain and inflammation, which can make a dog feel better and move more, potentially injuring the joint further. Your veterinarian will weigh these risks against the benefits for your dog's specific condition. The US Food and Drug Administration provides guidance on safe use of pet medications, and the American Veterinary Medical Association offers resources on working with your veterinarian to manage long-term treatment.

What You Should Do Now

Write down the date of the injection and the name of the drug if you know it. Keep a simple log of your dog's water intake, urination frequency, and appetite for the next two weeks. This information helps your veterinarian decide whether the side effects are within normal range or need attention.

Do not give your dog any other medication, including over-the-counter human drugs, without asking your veterinarian first. Some medications interact badly with steroids. Your veterinarian determines the correct dose for any future injections based on your dog's weight, health status, and the condition being treated. Never adjust a dose on your own.

If your dog's side effects are mild and improving, you can watch at home for 48 hours. If they get worse, or if new signs appear, call your veterinarian. The MSD Veterinary Manual provides reliable information on corticosteroid use in pets, and the American Animal Hospital Association offers guidance on when to seek veterinary care. Your veterinarian is the best source of advice for your dog's specific situation.

When Hands-On Care Is Required

Some situations in this article cannot be managed remotely. If your dog shows any of the following after a steroid injection, seek in-person emergency care immediately:

• Collapse, fainting, or inability to stand
• Difficulty breathing, wheezing, or rapid breathing at rest
• Swelling of the face, muzzle, or throat
• Hives covering a large area of the body
• Vomiting or diarrhea that continues for more than a few hours
• Blood in vomit or stool
• Seizures
• Sudden severe weakness or lethargy

These signs can indicate anaphylaxis, a severe allergic reaction, gastrointestinal ulceration, or a metabolic crisis. Do not wait to see if they improve. Do not attempt video consultation first. Call your nearest emergency veterinary hospital and go there directly.

What You Can Do at Home Right Now

For most dogs, the first 24 to 72 hours after a steroid injection bring mild, temporary changes. Your job is to observe, measure, and keep your dog comfortable.

What to watch and write down:

• Water intake. Count how many times your dog drinks in a day, or measure how much water you refill in the bowl.
• Urination frequency. Note how often your dog asks to go out and whether accidents happen indoors.
• Appetite. Record whether your dog eats normally, eats more, or refuses food.
• Energy level. Note whether your dog seems restless, agitated, or unusually tired.
• Panting. Count breaths per minute while your dog rests quietly. Normal resting rate is usually 10 to 30 breaths per minute, but panting after a steroid injection is common and not always dangerous.
• Vomiting or diarrhea. Note how many times in an hour and what the material looks like.
• Gum color. Lift the lip and look. Healthy gums are pink. Pale, white, blue, or brick-red gums are urgent signs.

What you can do:

• Offer fresh water frequently. Increased thirst is expected, so keep the bowl full and clean.
• Feed small, bland meals if your dog's stomach seems unsettled. Boiled chicken and white rice are reasonable options, but only if your dog is otherwise acting normally.
• Keep your dog calm and cool. Steroids can raise body temperature and cause panting, so avoid vigorous exercise and hot environments.
• Provide a quiet, comfortable place to rest.

What you must not do:

• Do not give any additional steroid medication, whether oral, topical, or injectable. The dose and timing must come from your veterinarian.
• Do not give human anti-inflammatory drugs such as ibuprofen, naproxen, or aspirin. These can cause severe stomach ulcers, kidney damage, or bleeding, especially when combined with steroids.
• Do not give any other medication, including over-the-counter products, without asking your veterinarian first.
• Do not reduce your dog's food or water to "balance out" the effects. That can cause dehydration or blood sugar problems.
• Do not assume a second injection is safe because the first one seemed fine. Every dose carries risk.

Timeline of Expected Side Effects

When to Call the Veterinarian

Call your veterinarian if you observe any of the following:

• Vomiting more than twice in 24 hours
• Diarrhea that lasts more than 24 hours or contains blood
• Refusal to eat for more than 24 hours
• Extreme lethargy, meaning your dog will not get up or respond normally
• Panting that continues for hours without stopping, even at rest
• Drinking so much water that the bowl empties repeatedly and urination becomes constant
• Any sign of an allergic reaction, such as facial swelling or hives
• Any new symptom that appears more than a week after the injection

If you are unsure whether a sign is serious, call your veterinary clinic and describe what you see. They can tell you whether to come in or continue monitoring at home.

What a Veterinary Visit Usually Involves

When you bring your dog in for a steroid-related concern, the veterinarian will start with a history. Expect questions about when the injection was given, what dose was used, what signs you have noticed, and whether your dog has any other health conditions.

The physical examination will include taking a temperature, listening to the heart and lungs, feeling the abdomen, and checking hydration status by looking at gum moisture and skin elasticity. The veterinarian may also check for signs of pain, especially in the stomach area.

Common tests include bloodwork to check kidney and liver function, blood sugar levels, and electrolyte balance. A urine sample may be collected to check for infection or concentrated urine. In some cases, imaging such as ultrasound may be recommended to look for ulcers or other internal problems.

The cost of a visit depends on what is needed. A basic examination typically ranges from 50 to 150 dollars. Bloodwork adds roughly 100 to 300 dollars. Imaging and hospitalization can raise the total considerably. Prices vary widely by region and clinic, so ask for an estimate before agreeing to tests. The most important factor driving cost is the severity of the signs and how many tests are needed to rule out serious complications.

When an Online Vet Can Help, and When It Cannot

A remote consultation is useful for early or mild presentations. If your dog is drinking a bit more than usual, panting occasionally, or eating more after an injection, a video call can help you decide whether a visit is needed. It is also helpful for rechecking a known problem, asking whether a specific sign warrants a trip to the clinic, or following up on a chronic condition where the diagnosis is already established.

A remote veterinarian can take a detailed history, watch your dog move and breathe on video, and give advice about monitoring and when to seek in-person care. In many states, they can prescribe medications, but prescribing rules differ by state and some require an in-person examination first.

What a remote consultation cannot do is examine your dog physically. The veterinarian cannot palpate the abdomen to check for pain, listen to the heart and lungs, take a temperature, run bloodwork, or perform imaging. These limitations matter. A dog with a painful abdomen, a fever, or abnormal bloodwork can look completely normal on a video call.

Use remote care for questions and reassurance. Use in-person care for anything that involves physical examination, testing, or emergency signs. When in doubt, choose the in-person visit.

Common Mistakes Owners Make

Many owners accidentally make things worse without meaning to. The most common error is stopping the injection plan too early. A steroid injection can take several days to reach full effect, and some dogs seem worse on day two before improving on day three. If you stop pursuing treatment because you think it failed, you may miss the benefit.

Another frequent mistake is giving other medications without asking first. Steroids change how the body handles many drugs, including common pain relievers. Some human pain medications are dangerous for dogs even on their own. Combining them with a steroid injection can cause stomach ulcers or kidney problems. Always confirm with your veterinarian before giving any other product, including flea preventives or supplements.

Owners also confuse side effects with the original disease returning. Increased thirst, more urination, and a bigger appetite are expected effects of the injection, not signs that the condition worsened. Knowing which signs belong to the medication helps you avoid unnecessary worry and unnecessary calls.

A third mistake is skipping the follow-up visit. The injection may control signs for weeks, but the underlying condition still needs monitoring. Your veterinarian needs to see your dog again to decide whether another injection is needed, whether the dose should change, or whether a different treatment would be safer long term.

How to Reduce the Chance of It Happening Again

You cannot always prevent the underlying condition that led to the injection, but you can reduce the chance of repeated steroid use. Ask your veterinarian whether a different class of medication could manage the problem. Many allergic and inflammatory conditions respond to newer drugs that do not carry the same long-term risks as steroids.

Keep your dog at a healthy weight. Extra body fat makes inflammation worse and can increase the dose needed to control signs. Regular gentle exercise and a consistent diet help many dogs stay stable for longer between treatments.

Track your dog's response in writing. Note the date of the injection, the signs you saw, and how long the benefit lasted. This record helps your veterinarian see patterns and adjust the plan. The FDA's guidance on safe use of pet medications explains why keeping accurate records and following instructions matters.

If your dog has repeated flare-ups, ask about allergy testing, dietary changes, or environmental controls. Reducing the trigger can reduce the need for future injections.

Recovery and Ongoing Management

Most dogs return to normal within a few days. The injection site may feel firm or tender for up to a week. Increased thirst and urination usually peak in the first 3 to 5 days and settle within 2 weeks. Appetite often increases during the same window.

The underlying condition determines how long management lasts. A single allergic reaction may need only one injection. A chronic condition such as inflammatory bowel disease or severe arthritis may require repeat injections, but your veterinarian should aim for the lowest effective dose and the longest possible interval between doses.

Watch for the return of the original signs. If your dog's symptoms come back sooner than expected, that is useful information for your veterinarian. It may mean the dose was too low, the condition has changed, or a different diagnosis should be considered.

Long-term steroid use requires regular blood work. Your veterinarian will likely check liver values, kidney function, and blood sugar at each recheck. These tests catch problems early, when they are easier to manage. The American Veterinary Medical Association's pet owner resources describe how routine monitoring supports safer treatment.

Recovery is not always linear. Some dogs have a good week, then a rough day. That is normal. What matters is the overall trend and whether your dog is eating, drinking, and behaving like themselves.

Frequently Asked Questions

How long do steroid injection side effects last?

Most side effects appear within the first 24 to 48 hours and fade over 1 to 2 weeks. Increased thirst and urination usually peak around day 3 to 5. Appetite changes often last a few days to a week. If any side effect lasts longer than 2 weeks or gets worse instead of better, call your veterinarian. The duration also depends on the specific steroid used and the dose given. Your veterinarian can tell you what timeline to expect for your dog's particular injection.

Can my dog take their regular medications with a steroid injection?

Not automatically. Steroids interact with many common drugs, including anti-inflammatory pain medications, some antibiotics, and certain heart medications. Some combinations increase the risk of stomach ulcers or kidney damage. Show your veterinarian a complete list of everything your dog takes, including supplements and flea or heartworm preventives. Do not add or stop any medication without explicit approval. Your veterinarian will adjust doses or timing to keep your dog safe.

Will my dog need more injections in the future?

That depends on the underlying condition. Some dogs need only one injection for a single flare-up. Others with chronic conditions may need repeat injections, but your veterinarian should try to extend the interval between doses and use the lowest effective dose. If your dog needs frequent injections, ask about alternative treatments. Newer non-steroid options exist for many allergic and inflammatory conditions and may reduce the need for repeated steroid use.

Is it normal for my dog to drink and urinate much more?

Yes, this is one of the most common and expected effects of a steroid injection. Steroids affect the kidneys and increase thirst. You may see your dog at the water bowl more often and need more frequent bathroom breaks. This usually peaks in the first week and settles within 2 weeks. Make sure fresh water is always available. If your dog cannot urinate, or is straining without producing urine, seek emergency care immediately.

Can a steroid injection cause diabetes in my dog?

Steroids can raise blood sugar, and repeated high doses can trigger diabetes in susceptible dogs. This is more of a concern with long-term use than with a single injection. Your veterinarian may check blood sugar before and during treatment, especially if your dog is older or overweight. Signs of diabetes include excessive thirst, increased urination, weight loss despite a good appetite, and lethargy. Report these signs promptly if they appear.

What should I do if my dog seems worse after the injection?

First, determine what "worse" means. Mild drowsiness, increased thirst, or a temporary increase in the original signs can happen in the first few days. If your dog is vomiting repeatedly, has diarrhea with blood, collapses, has trouble breathing, or seems unable to stand, treat this as an emergency and go to a veterinary hospital immediately. For milder concerns, call your veterinarian during business hours and describe exactly what you are seeing and when it started.

Related Clinical & Scientific Guides

• What Are the Side Effects of Bravecto for Dogs? What to Watch For
• Can You Give Your Dog Human Allergy Medicine? Whats Safe
• Can You Give Your Dog Dramamine for Car Sickness?

References and Further Reading

• FDA Center for Veterinary Medicine Animal Drug Information
• FDA Safe Use of Pet Medications
• AVMA Pet Owner Resources
• MSD Veterinary Manual Pet Owner Version
• AAHA Pet Owner Resources

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This article is general educational information for pet owners. It is not a substitute for veterinary diagnosis, examination, or treatment. If your pet is showing severe or rapidly worsening signs, contact an emergency veterinary hospital immediately.