Dog Anesthesia Side Effects: What to Know

At some point in your dog’s life, there may come a day where anesthesia is required because a surgical procedure has become necessary. Anesthesia is comprised of certain drugs used to help depress the nervous system of your dog so that they are calm, sedated, and pain-free during their procedure. Note that when a dog requires general anesthesia, it means they will actually be unconscious for a period of time and unaware of their surroundings.

Though general anesthesia is necessary, it can be disconcerting to see your dog unconscious, and there are dog anesthesia side effects. However, more often than not, the benefits outweigh the risks, and anesthesia is a necessary component to helping ensure your dog feels no pain and that his muscles stay relaxed and lax. Dog anesthesia helps keep your canine from fighting against a potentially life-saving procedure or a procedure that will improve his quality of life.

Thankfully, veterinary medicine has grown over the years and the anesthetic agents that are used today are both predictable as well as reversible because of the improvements that have been made to them. That means that the risk of dog anesthetic side effects has gone down considerably in today’s practice of vet medicine.

Note that there are other types of anesthesia as well, such as local anesthesia which is often used on the skin or in the mouth during dental work, and spinal anesthesia, used to create a lack of sensation in a certain part of the body. There are less dog anesthesia side effects to these agents, but they aren’t the same thing as putting a dog under general anesthesia to undergo surgery.

Dog Anesthetic Side Effects and Risks

Any time medications are used, including anesthetic drugs, there is the risk of unpleasant reactions. Reactions can range from mild and no big deal, or catapult into catastrophic and even life-threatening situations.

However, in most cases, risk of death is more likely on the drive to the hospital than from dog anesthesia. Mild dog anesthetic side effects include injection site swelling or a faint decrease in a dog’s cardiac output. Catastrophic effects include anaphylactic shock or death.

Other adverse reaction risks to dog anesthesia include not making sure your pup has been fasting prior to being anesthetized. If the pet hasn’t properly fasted, your dog may vomit while unconscious and the vomit can be accidentally sucked into the lungs.

Sucking vomit into their lungs can trigger an episode of aspiration pneumonia which can be life-threatening. More rare reactions to dog anesthesia are side effects like seizures, visual impairments, clotting disorders (like von Willebrand’s disease in dogs), and system organ failures of the liver, kidney, or heart.

Known Risk Factors of Dog Anesthesia

Dogs that suffer from canine Cushing’s disease and Addison’s disease, hypothyroidism, diabetes, and also dogs that are obese or have kidney or canine liver disease should require extra caution and consideration before going under anesthesia. It’s important to discuss with your vet all of your dog’s potential risk factors and proceed from there. If the benefits of the procedure are larger than the risks of anesthesia to your dog, then anesthesia may be the way to go.

Anesthesia Protocols

When using general anesthesia, there are certain protocols that are followed for all breeds of dog. Generally, a dog needs to undergo preparation and patient assessment before being given anesthesia to evaluate any potential risk factors. A dog must also be given premedication prior to general anesthesia, such as sedatives and pain medication. This is usually done an hour before the procedure.

Dogs may also be given induction drugs to propel them from being conscious into an unconscious state. Additionally, all dogs will be monitored during anesthesia, including monitoring their respiration, heart rate, blood pressure, body temperature, and other central nervous system functions.

And finally, all dogs are monitored during recovery as well. This process is usually overseen by staff that are trained in detecting any recovery problems specifically related to anesthesia and its effects on an animal’s system.

Breed Risks for Anesthesia

Another thing to keep in mind is that not all dogs are a good candidate for anesthesia. Different breeds have genetic differences, as well as body conformation differences that can play a very important role in delivering the anesthetic drugs to their system safely.

There are certain breeds that are more responsive to anesthesia, which puts them at a higher risk for overdose because less of the drugs are needed to put them under. Other breeds, such as Boxers with smushed-in noses, run the risk of airway an obstruction. Their risk of course, is greater than dogs with longer snouts, because dogs with longer snouts have better-formed airways.

Certain breeds take longer to recover from anesthesia than others as well, and breeds that are considered high risk already tend to also suffer from metabolic disorders. These breeds pose an even greater risk under anesthesia.

Dogs with heart disease, whether their disease is acquired or congenital, are risky too. A consultation should be done before any dog anesthetic is given and any procedure is performed for all dogs for maximum safety and no lasting dog anesthesia side effects. Every dog’s experience under anesthesia must be customized and tailored specifically for them.

What Can Owners Do to Minimize Risks?

A patient assessment and pre-surgical physical exam as well as urine, blood tests, and radiograph exams are important in helping your vet discover any clinical or sub-clinical issues that could pose an anesthesia risk. ECGs and chest radiographs are often indicated for older dogs to make sure there are no heart or lung conditions going on that could increase a dog’s risk of an adverse side effect.

Another thing your vet will likely do is create an immediate IV line so that it is already in place should it be needed. This is so your vet can administer any emergency drugs necessary, plus anesthetic medications and fluids can also be given through that same line.

IV fluids are important in helping a dog maintain their blood pressure during anesthesia and it also helps to replace lost fluids during surgery.IV fluids help to speed up your dog’s recovery by creating a dilution effect in your dog’s bloodstream and enhancing the dog’s metabolism. This helps them to eliminate the anesthetic agents through their liver and kidneys faster and recover more quickly, resulting in a happier, healthier dog on an accelerated timeline.

Not only do dogs generally wake up more quickly when administered IV fluids, they also reduce their likelihood of developing any kidney dysfunction or failure in the two weeks following dog anesthesia. Remember that most dogs will have no issues using anesthesia, but your vet’s primary goal is to make sure your dog doesn’t fall into that 2% that does suffer from adverse reactions. Always better to be safe than sorry.

It’s also important to make sure your vet has a complete medical history to refer to about your dog, especially if your dog has been seen at another clinic before or isn’t seen consistently in one location.

Your vet should be made aware of the medications and supplements your dog is currently taking or has taken in the last few weeks, any pre-existing medical issues, as well as any previous diagnostic testing results, known drug reactions, and whether or not your dog has had any surgical procedures or anesthesia in the past. Your vet may also want to know your dog’s vaccine status and when their last heat cycle may have been, so it’s a good idea to have that info ready and available as well.

Dog Anesthesia After Effects

Dogs can experience some after effects following general anesthesia. These effects might make your dog seem a little groggy or drunk. Don’t worry, those disorientated, slightly wobbly on his feet signs and symptoms should resolve fairly quickly. In fact, you may not even see them at all. For now, here are some of the dog anesthesia after effects you can keep an eye out for.


Dog nauseousness after a round with anesthesia is very normal. Once your dog has been discharged, your vet may give you some precise feeding parameters designed to help mitigate the nausea. In most cases, your dog should be able to tolerate a small meal, but always defer to your vet’s wisdom and instructions, and if your dog doesn’t want anything to eat until the following day, that’s okay.


Every dog is different when it comes to recovering from anesthesia. Because anesthesia can affect different breeds and even individual dogs within a breed differently, no recovery is quite like the other.

Some dogs can bounce back immediately as though they were never under anesthesia, while other dogs may appear as though they are clumsy and groggy for a few days afterward. You also may notice your dog dozing a little more than usual until the drugs are finally gone from his system. It’s a bit like a doggie hangover and encouraging your dog to drink may help speed up the process. In most cases, you should see your normal dog back within 18 to 24 hours.


Along with groggy behavior, you may notice your dog seems to have a clumsy or unsteady gait as they walk. This is another effect of anesthesia that affects your dog’s nervous system and creates poor depth perception. As you could assume, this making walking difficult.

The best thing to do for your dog is to find him somewhere safe and quiet he can curl up for a while, so he can sleep it off. If there are places your dog has to navigate that are somewhat precarious, such as getting in and out of your car, or going up and down stairs, you may need to assist to prevent your dog from falling.

Note also that you may not always see poor balance in a dog that has been under anesthesia, because some vets will choose to keep the dog under their care until those effects have dissipated. However, if your dog is discharged before those effects have worn off completely, then you will notice them. In most cases, how soon your vet discharges your dog depends on the reason your dog was under anesthesia in the first place, and your own level of experience and comfort in caring for your dog properly as he recovers.

Behavioral Changes

Sometimes a dog may get back home in familiar surroundings and seem as though they are not really responding to anything. They might not respond to familiar people or other family animals either. Don’t freak out too much, these behavioral changes are part for the course with anesthesia and tend to resolve on their own within a few days.

Note however, that because of these behavioral changes, no matter how your dog usually behaves, it is wise to let your dog stay to himself and not handle him too much. It is also wise not to leave kids or other pets with your recovering dog without supervision, just to be safe.

Chilling Effect

Finally, another dog anesthesia after effect your dog may experience as they recover is having difficulty maintaining his regular level of body heat. Some anesthetics can cause dilation of blood vessels in the skin, which results in heat loss. To combat this effect, make sure you have a nice cozy and warm doggie bed and blanket ready for your furry friend to cuddle into, and keep the room warm if you can, but not so warm it’s stifling.

As you can see, dog anesthesia side effects and after effects can range in scope and severity, but your vet’s job is to minimize all of those risks as much as they possibly can. Thoroughly discuss your beloved canine’s options with a professional, and then make your decisions armed with knowledge and awareness of all potential risks.

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