Methocarbamol for dogs is a muscle relaxer that vets may prescribe to relieve muscle spasms in dogs with conditions like intervertebral disc disease (IVDD). To help dog parents learn about this medication, integrative veterinarian Dr. Julie Buzby explains the uses, dosage, side effects, and contraindications of methocarbamol for dogs.
Last week I diagnosed one of my favorite Dachshund patients with intervertebral disc disease (IVDD). Poor Frank’s back was tight and painful. And he looked so pathetic as he stood there on my exam table, trembling and hunched over. He was far from his usually happy, wiggly self that day.
As it turns out, Frank’s mom had also recently suffered a back injury. So she understood all too well how her pup was feeling. Since muscle relaxers really helped her back spasms, she asked me if there were muscle relaxers that Frank could safely take.
She was spot-on with that question. I too was thinking that Frank could benefit from a muscle relaxant—methocarbamol, to be exact—as part of his treatment plan.
What is methocarbamol for dogs?
As I explained to Frank’s mom, methocarbamol is a muscle relaxer used to treat skeletal muscle trauma or acute (i.e. rapid-onset) muscular inflammation in dogs, cats, and horses. Its veterinary trade name is Robaxin®-V. Additionally, methocarbamol is a human drug, and goes by the trade names Robaxin®, Robinax®, and Robaximol®.
How does methocarbamol work?
The exact mechanism of action isn’t well understood. But we do know that methocarbamol works on the nerve cells (i.e. neurons) in the spinal cord that send signals to the skeletal muscles. These neurons control the muscles that move the legs, back, neck, and other parts of the skeleton.
When a dog experiences muscle injury or inflammation, contracts a disease like tetanus, or is exposed to certain toxins, these neurons may send abnormal or overly-reactive signals to the muscles. The end result is muscle spasms, tremors, or muscle rigidity.
Researchers believe that methocarbamol is able to dampen or decrease the abnormal signals, which helps relieve the muscle tremors or spasms. Yet the methocarbamol doesn’t affect the ability of the neurons to send the signals necessary for normal muscle tone and muscle contraction. This means that therapeutic doses can often relieve spasms without significantly affecting a dog’s ability to walk.
Since methocarbamol works on the spinal cord, which is part of the central nervous system, it does also have some sedative effects. Vets do not, however, typically use it strictly as a sedative.
What is methocarbamol used for in dogs?
Because of its ability to reduce muscle spasms and tremors due to nerve hyperreactivity, vets may use methocarbamol as part of the treatment for musculoskeletal or neurologic problems such as:
- Intervertebral disc disease (IVDD in dogs)—methocarbamol may play a part in helping a dog recover from IVDD without surgery or reducing spasms after IVDD surgery for dogs
- Compressive myelitis (i.e. inflammation of the spinal cord that results from compression) or spinal cord injury
- Inflammation of the muscles, ligaments, tendons, or joints
- Muscle, ligament, or tendon injury
- Muscle spasms before or after surgery
Additionally, vets may use methocarbamol to treat muscle spasms, rigidity, or tremors due to:
- Chocolate toxicity in dogs (i.e. methylxanthine toxicosis)
- Serotonin syndrome—a condition that may occur when there is too much serotonin in the body due to overdosing on, or inappropriately combining, anxiety medications like trazodone for dogs, fluoxetine, etc.
- Strychnine poisoning
- Metaldehyde toxicity (e.g. slug bait toxicity)
- Tremorgenic mycotoxins (i.e. toxins produced by certain fungi)
- Tetanus in dogs—a bacterial infection that causes severe muscle rigidity and spasms
Is it ok to use methocarbamol with other medications?
While methocarbamol does a great job of decreasing the severity of muscle tremors and spasms, it isn’t a pain medication. This isn’t a problem for toxicity cases. But many of the orthopedic causes of muscle spasms are painful. Therefore, vets frequently end up combining methocarbamol with medications that reduce pain and/or inflammation.
For example, it isn’t uncommon for a veterinarian to prescribe methocarbamol and carprofen (or another non-steroidal anti-inflammatory) for IVDD. Or, while a less common treatment for IVDD now, the vet may recommend using prednisone for dogs and methocarbamol together in some cases.
Alternatively, depending on your dog’s situation, your vet may prescribe methocarbamol and gabapentin for dogs for some orthopedic problems. Thankfully, it is safe to use methocarbamol with most other medications your vet may want to prescribe. This gives your vet lots of options.
Medications to avoid combining with methocarbamol
However, there are a few medications that don’t mix well with methocarbamol. Because of its sedative effects, methocarbamol should be used with caution with any other medications that cause central nervous system depression. For example, methocarbamol and tramadol for dogs can be safely combined in some situations but may cause increased sedation.
Additionally, methocarbamol should not be used with anticholinesterase agents like pyridostigmine, a treatment for myasthenia gravis in dogs. This is because methocarbamol can inhibit the activity of the pyridostigmine, resulting in severe muscle weakness.
Methocarbamol can also interact negatively with the following medications:
- Anticholinergics (e.g., atropine, glycopyrrolate)
- Buprenorphine (a narcotic pain reliever)
- Mirtazapine (an appetite stimulant for dogs)
- Selective serotonin reuptake inhibitors or SSRIs (e.g., fluoxetine)
Are there dogs who should not take methocarbamol?
Additionally, there are several situations where methocarbamol may not be a good choice. Patients who have kidney failure in dogs should not take methocarbamol. Neither should dogs who have had adverse reactions to it in the past.
The safety of methocarbamol for pregnant or lactating dogs is unknown. However, your vet may decide to prescribe it if the benefits outweigh the risks.
What is the methocarbamol dosage for dogs?
Your veterinarian will take your dog’s current medications and supplements, ongoing medical conditions, and current status into account before deciding to prescribe methocarbamol. If your vet feels that methocarbamol is right for your dog, he or she will discuss the dosage and instructions with you. Like most medications, your dog’s methocarbamol dose will be based on his or her weight.
Methocarbamol is available as an injectable solution (for in-hospital use only). Plus, it comes as a 500 mg tablet or 750 mg tablet, both of which should be stored at room temperature. It is sometimes also possible to have methocarbamol compounded into a liquid, powder, or capsule. This gives some flexibility for dogs who won’t take pills or small dogs who need a lower dose than the typical tablet size will allow.
How soon will you see the effects of methocarbamol?
If your dog suffered an injury or is dealing with post-surgical muscle spasms, the vet will most likely send him or her home with oral methocarbamol on a twice-a-day or three-times-a-day dosing schedule. You can expect it will kick in after one to two hours. And you should be able to see a difference in your dog after the first day or so.
Alternatively, if your dog is experiencing muscle tremors due to a toxin, tetanus, or serotonin syndrome, the vet may administer methocarbamol solution intravenously (i.e. in a vein). In this situation, the vet will often see the muscle spasms or tremors subside or lessen within a few minutes.
How long can a dog be on methocarbamol?
Most of the time, a dog will just be on methocarbamol for a short period of time. Dogs who are experiencing muscle spasms from an injury or surgery may take methocarbamol for a week or two. And then they may not need it anymore.
However, there are occasionally situations where a dog may be on methocarbamol long term. For example, some dogs who have muscle spasms secondary to osteoarthritis in dogs may benefit from long-term methocarbamol, in addition to other medications or therapies to relieve arthritis pain in dogs. In that case, the vet will monitor the dog periodically with an examination, blood work, urinalysis, etc. Your veterinarian will let you know what is right for your dog’s particular situation.
What are the side effects of methocarbamol?
The veterinarian will also review the common side effects of methocarbamol, which, thankfully, are typically mild or nonexistent. Some dogs won’t show any adverse effects at all. Others may have a bit of drooling or nausea (sometimes signaled by a dog who keeps licking his or her lips). While it is fine to give the methocarbamol on an empty stomach, it does seem that giving it with food can help reduce any nausea or vomiting.
Additionally, some dog parents may notice that their dog’s urine has a blue or green tinge to it. This may seem a bit odd, but it isn’t harmful to the dog’s health.
It’s also worth knowing that if some of the injectable methocarbamol gets outside the vein, it can damage the surrounding soft tissues. Therefore, if your dog’s leg looks inflamed or swollen and he or she recently received an intravenous methocarbamol injection, please contact your veterinarian.
While severe side effects aren’t common, they tend to be associated with high doses of methocarbamol. More significant adverse effects include excessive sedation, muscle weakness, and a dog who is wobbly and off balance (i.e. ataxic).
Symptoms of a methocarbamol overdose in dogs
In addition to those signs, overdoses of methocarbamol may also cause excessive panting and difficulty breathing. Plus, dogs who overdose can also lose their righting reflex. This means they cannot get back to a normal upright position if they fall over.
In extreme cases, a methocarbamol overdose can lead to respiratory paralysis and death. This is why it is important to make an emergency vet visit or call ASPCA Animal Poison Control Center immediately if you suspect an overdose.
My patient’s experience with methocarbamol
After discussing Frank’s case with his mom and going over his medications (including methocarbamol), I sent them on their way. Happily, when I called to check on Frank the next day, his mom reported that he was already feeling a little better. And when he came in for his two-week recheck, he was back to his usually happy self.
Work with your veterinarian
If your vet thinks your dog might benefit from methocarbamol, don’t be afraid to give it a try. It isn’t going to relieve pain directly. But getting rid of the muscle spasms can definitely help your dog be more comfortable. Often, methocarbamol, in combination with pain medication (or whatever medications or therapies your vet recommends) can help get your pup’s paws on the path to recovery quickly.