Suspect poisoning? US: ASPCA Poison Control (888) 426-4435 · UK: 01202 509 000 · Severe symptoms → nearest emergency vet now.

Muscle Relaxants (Baclofen, Cyclobenzaprine)

A single 10 mg baclofen tablet can be enough to cause severe signs in a small dog, and just two or three have killed dogs.

Last reviewed: 2026-09-05 · Reference ranges: ASPCA, Pet Poison Helpline & Merck Veterinary Manual

Treat this as a potential emergency — not a "wait and see" situation.
Contact your vet before symptoms even appear.

US: ASPCA Animal Poison Control (888) 426-4435 · Pet Poison Helpline (855) 764-7661

UK: Veterinary Poisons Information Service 01202 509 000

Why is it dangerous to pets?

Baclofen is a central muscle relaxant used for back spasm and MS. In dogs it causes deep sedation, loss of coordination, tremors and, in severe cases, respiratory depression and death.

Human tablets are 10–20 mg, which is enormous for a pet — reports describe severe poisoning in dogs from one or two tablets.

Why speed matters

Delaying care significantly worsens outcomes. Some signs appear hours or days later, so "looks fine right now" is not a reason to wait.

Symptoms of muscle-relaxants poisoning

  • Deep sedation, difficulty waking
  • Wobbliness, unable to stand
  • Head tremors, twitching, rigidity
  • Vomiting, drooling
  • Slow shallow breathing, coma (emergency)

What to do right now

  1. Treat any baclofen ingestion as an emergency and go to the vet now.
  2. Bring the bottle so the exact dose can be calculated.
  3. Support the head so the airway stays open if the pet is sedated.
  4. Do not induce vomiting in a drowsy pet.
If your pet shows any of the signs above, go to the nearest emergency vet now and call ahead.

Sources & further reading

  • ASPCA Animal Poison Control — pet poison database & dosage references
  • Pet Poison Helpline — toxicology triage guidelines
  • Merck Veterinary Manual — toxicology monographs
  • Vets Now (UK) — emergency toxicosis guidance