By Rania Gollakner, BS, DVM, MPH

What is methocarbamol?

Methocarbamol (brand names: Robaxin®, Robinax®, Robaximol®) is a muscle relaxant used to reduce muscle spasms associated with inflammation, injury, intervertebral disc disease, and certain toxicities. It is used only in companion animals.

Its use in cats, dogs, and horses to treat certain muscular skeletal conditions is on label; however, its use at certain doses is ‘off label’ or ‘extra label’. Many drugs are commonly prescribed for off label use in veterinary medicine. In these instances, follow your veterinarian’s directions and cautions very carefully as their directions may be significantly different from those on the label.

How is methocarbamol given?

Methocarbamol is given by mouth in the form of a tablet. It can also be given as an injection in the clinic setting. It may be given with or without food; however, if vomiting occurs when dosed on an empty stomach, give future doses with food.

This medication will take effect quickly, in about 1 to 2 hours, and improvement in clinical signs should follow.

What if I miss giving my pet the medication?

If you miss a dose, give it when you remember, but if it is close to the time for the next dose, skip the dose you missed and give it at the next scheduled time, and return to the regular dosing schedule. Never give your pet two doses at once or give extra doses.

Are there any potential side effects?

The most common side effect includes sleepiness. Other side effects include drooling, vomiting, weakness, and incoordination. Serious side effects include severe or continued vomiting or weakness. This medication may also darken the color of the urine or cause blue-green urine, but this is not harmful.

This short-acting medication should stop working within 24 hours, although effects can be longer in pets with liver or kidney disease.

Are there any risk factors for this medication?

Do not use methocarbamol in pets that are allergic to it. It should be used cautiously in pets with kidney disease, or in pregnant or nursing pets, as well as in working animals, as this medication may affects their ability to perform.

Are there any drug interactions I should be aware of?

The following medications should be used with caution when given with methocarbamol: anticholinergics, buprenorphine, central nervous system depressants, mirtazapine, pyridostigmine, or selective serotonin reuptake inhibitors (SSRIs).

Be sure to tell your veterinarian about any medications (including vitamins, supplements, or herbal therapies) that your pet is taking.

Is there any monitoring that needs to be done with this medication?

Your veterinarian may monitor your pet to be sure that the medication is working. Monitor for sedation level and level of muscle relaxation. Monitor for serious side effects.

How do I store methocarbamol?

Store the tablets at room temperature between 68°F and 77°F (20°C and 25°C), protected from moisture and light.

What should I do in case of emergency?

If you suspect an overdose or an adverse reaction to the medication, call your veterinary office immediately. If they are not available, follow their directions in contacting an emergency facility. Do not induce vomiting at home unless directed by a veterinarian.

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