Pet Safety / Compounds / Methocarbamol

Is Methocarbamol safe for dogs and cats?

Low risk for pets

Methocarbamol (Robaxin-V) is FDA-approved (NADA) for dogs for treatment of muscle hypertonicity associated with tetanus and spastic conditions. Dosed at 44–220 mg/kg IV for acute tetanus, or 132 mg/kg orally for muscle spasm. Well-tolerated at therapeutic doses. Adverse effects in dogs: sedation, salivation, ataxia, nausea (dose-dependent). The wide therapeutic index in dogs allows relatively high doses for tetanus management. Unlike cats, dogs do not appear to have the specific hepatotoxic reaction associated with benzodiazepine use. Can be used concurrently with supportive care, nutritional support, and other tetanus management measures in dogs. Not used for anesthetic pre-medication or sedation in dogs due to unreliable sedative effect at standard doses.

What is methocarbamol?

The IUPAC name is [2-hydroxy-3-(2-methoxyphenoxy)propyl] carbamate.

Also known as: [2-hydroxy-3-(2-methoxyphenoxy)propyl] carbamate, Robaxin, Metocarbamol, Miolaxene.

IUPAC name
[2-hydroxy-3-(2-methoxyphenoxy)propyl] carbamate
CAS number
532-03-6
Molecular formula
C11H15NO5
Molecular weight
241.24 g/mol
SMILES
COC1=CC=CC=C1OCC(COC(=O)N)O
PubChem CID
4107

Risk for dogs

Low risk

Methocarbamol (Robaxin-V) is FDA-approved (NADA) for dogs for treatment of muscle hypertonicity associated with tetanus and spastic conditions. Dosed at 44–220 mg/kg IV for acute tetanus, or 132 mg/kg orally for muscle spasm. Well-tolerated at therapeutic doses. Adverse effects in dogs: sedation, salivation, ataxia, nausea (dose-dependent). The wide therapeutic index in dogs allows relatively high doses for tetanus management. Unlike cats, dogs do not appear to have the specific hepatotoxic reaction associated with benzodiazepine use. Can be used concurrently with supportive care, nutritional support, and other tetanus management measures in dogs. Not used for anesthetic pre-medication or sedation in dogs due to unreliable sedative effect at standard doses.

Risk for cats

Moderate risk

Methocarbamol is sometimes used off-label in cats for tetanus and muscle spasm management, though veterinary pharmacokinetic data in cats are limited. Cats have reduced glucuronidation capacity for many drugs, but methocarbamol's carbamate ester structure and metabolism may not be specifically problematic in cats (unlike propylene glycol or acetaminophen). Sedation and CNS depression are expected. Dosing in cats requires greater caution than dogs due to the more limited safety data. Oral bioavailability in cats may differ from dogs. Extrapolation from canine and equine pharmacokinetic data with appropriate dose adjustment is the current veterinary practice. Monitor for excessive CNS depression, ataxia, and nausea.

Regulatory consensus

1 regulatory bodyhas classified Methocarbamol.

AgencyYearClassificationNotes
US FDA (approved drug; non-scheduled; veterinary NADA)2021no carcinogenicity classification; FDA-approved muscle relaxant (Robaxin) and veterinary drug (Robaxin-V for dogs/horses); not a DEA controlled substance; not classified for carcinogenicity by NTP, IARC, or EFSA

Regulators apply different standards of evidence — animal-data weighting, exposure-pattern assumptions, epidemiological power thresholds — which is why two scientific bodies can review the same data and reach different conclusions. The disagreement is the data.

Where pets encounter methocarbamol

  • Industrial Facilities — Manufacturing plants, Chemical storage areas, Waste treatment sites
  • Occupational Environments — Factories, Warehouses, Transportation vehicles

Safer alternatives

Lower-risk approaches that achieve a similar outcome to Methocarbamol:

  • Alternative drug class; Non-pharmacological therapy; Lowest effective dose
    Trade-offs: Direct chemical substitution requires verification that the replacement does not introduce new hazards (regrettable substitution). Conduct full hazard assessment of proposed alternative before adoption.
    Relative cost: 1.2-2×

Frequently asked questions

Is methocarbamol safe for pets?

Methocarbamol (Robaxin-V) is FDA-approved (NADA) for dogs for treatment of muscle hypertonicity associated with tetanus and spastic conditions. Dosed at 44–220 mg/kg IV for acute tetanus, or 132 mg/kg orally for muscle spasm. Well-tolerated at therapeutic doses. Adverse effects in dogs: sedation, salivation, ataxia, nausea (dose-dependent). The wide therapeutic index in dogs allows relatively high doses for tetanus management. Unlike cats, dogs do not appear to have the specific hepatotoxic reaction associated with benzodiazepine use. Can be used concurrently with supportive care, nutritional support, and other tetanus management measures in dogs. Not used for anesthetic pre-medication or sedation in dogs due to unreliable sedative effect at standard doses.

What products contain methocarbamol?

Methocarbamol appears in: Manufacturing plants (Industrial facilities); Chemical storage areas (Industrial facilities); Factories (Occupational environments); Warehouses (Occupational environments).

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Sources (1)
  1. FDA Methocarbamol Robaxin Prescribing Information 2021: Not Controlled Substance; Guaifenesin Carbamate Ester; Not TCA No Anticholinergic; Robaxin-V NADA Dogs Horses Tetanus 44–220 mg/kg IV; Pediatric Tetanus Use; No Carcinogenicity Classification (2021) — regulatory

Reference data, not professional advice. Aggregates publicly available regulatory and scientific data; not a substitute for veterinary, medical, legal, or regulatory advice. Why we built ALETHEIA →