Methocarbamol

Major Uses

Methocarbamol is a muscle relaxant that can be administered orally or by injection. It is used in dogs and cats to treat acute inflammatory and traumatic conditions of the skeletal muscles, and also to treat muscular spasms. In horses, it is often given intravenously to treat the same conditions as listed for dogs and cats. Intravenous solutions of methocarbamol have also shown effectiveness in treating tremors associated with various toxicities in dogs and cats.

Common Precautions

Methocarbamol should be used cautiously in animals with known or suspected renal pathology. It is also known to increase symptoms and effects associated with acidosis and urea retention.

Some possible side effects of methocarbamol in dogs and cats include sedation, salivation, emesis, lethargy, weakness, and ataxia. In horses, methocarbamol can cause sedation and ataxia. It may also impair the ability of working animals because of its CNS depressant effects.

Methocarbamol should not be used in animals with a known allergy or hypersensitivity to the drug. A veterinarian should be contacted immediately if an overdose is suspected. Overdose symptoms in dogs and cats may include emesis, salivation, weakness, vomiting, and ataxia.

Storage

Methocarbamol should be kept at room temperature in a tight, light resistant, childproof container. The injection form should be kept away from conditions that may cause freezing. Refrigeration should be avoided, as precipitate may form. All doses should be carefully examined for haze or precipitate formation.

Administration

When methocarbamol is used as an injection in dogs and cats, a common dose is 44 mg/kg, unless being used to treat severe conditions of strychnine and tetanus, in which case a dose between 55-220 mg/kg is more appropriate. Doses should never be more, or add up to more than 330 mg/kg a day. When taken in tablet form for these same conditions, an initial dose is 132 mg/kg a day divided into doses given every 8-12 hours. After this initial dose, 61-132 mg a day given the same way should be administered for up to 5 days if no response is seen. For horses, a typical dose is 4.4-22 mg/kg. A more serious case may require doses of 22-55 mg/kg. If a dose is missed, it should be given as soon as possible. If it is almost time for the next scheduled dose, the missed dose should be skipped and the regular administration schedule should be resumed. Two doses should never be given at the same time, as overdose may occur.

Doses may vary in different species, when the drug is given by a different route or concurrently with other medications, and with regards to a patient's age, breed, and health status. A veterinarian's dosing instructions and/or those printed on the medication label should be followed closely.