The human product is the problem: the strength, the coating, or an added ingredient makes it wrong for a dog even when the active ingredient is familiar.
Cyclobenzaprine is a centrally acting muscle relaxant used mainly in human medicine. Merck notes some extra-label use in dogs, so it is inaccurate to say it is never used in veterinary care.
Call a vet or poison control now. Do not wait for symptoms.
ASPCA Animal Poison Control (888) 426-4435 or Pet Poison Helpline (855) 764-7661. A consultation fee may apply.
Educational reference. Not individualized veterinary advice.(more)
See this page's cited references for supporting information and our Sources page for the reference organizations we use. Citations do not imply that those organizations reviewed or endorsed DogSafe.
Part of Seizure, nerve and muscle medication on our medication safety hub.
Do not wait for symptoms and do not wait until you have filled in the form below. Call first, then use the checklist while you are on the phone.
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Exposure details to have ready
These are the questions a veterinarian or poison-control operator will ask. Fill in what you know and leave the rest blank. This tool does not estimate a dose or a risk score: medication risk depends on the exact ingredient, strength, and formulation, so the assessment has to come from the clinician on the call.
- Keep the package, blister pack, or prescription bottle. The strength and the full ingredient list are what make the advice specific.
- Do not induce vomiting unless a veterinarian or poison-control professional tells you to. It is the wrong move for several medications and can cause harm on its own.
- Do not give milk, food, salt, hydrogen peroxide, or any home remedy on your own.
- Do not give a second dose of anything to make up for one you think was missed.
- Count what is left in the packet, so the number missing can be worked out.
Your exposure summary
Read this down the phone or paste it into a message to your vet. It stays on your device; nothing here is sent to DogSafe.
Why Cyclobenzaprine (Flexeril) is dangerous
Cyclobenzaprine is a centrally acting muscle relaxant used mainly in human medicine. Merck notes some extra-label use in dogs, so it is inaccurate to say it is never used in veterinary care. Accidental ingestion still needs a product-specific assessment. Reported effects include salivation, vomiting and impaired coordination; severe exposures can affect the heart or cause seizures. There is no established minimum toxic dose that this page can turn into a safe threshold.
Part of the Methocarbamol guide
For related dog-safety questions and product-by-product answers, see the complete methocarbamol guide.
Signs to watch for
Drooling, vomiting, dry gums, poor coordination or a fast heartbeat; seizures or marked weakness needs emergency care.
Related items
Check the exact item or ingredient before assuming two similar exposures carry the same risk.
What to do next
Have the exact ingredient name, strength or concentration, amount missing, possible time, dog’s weight and current medications ready. Report chewed packaging and ask what to do before the next prescribed dose.
🚨Step-by-step: what to do in the first 10 minutes →Available 24/7. A consultation fee may apply.
FAQ
This page gives no dose or safe-exposure threshold. Follow the prescription for this dog; ask the veterinarian to confirm the product and any change to the schedule.
Prevent further access and keep the packaging. Do not induce vomiting or give a home remedy unless a veterinary professional directs you for this exposure.
Call promptly after an accidental ingestion, suspected extra dose, unknown amount or unexpected reaction. Breathing difficulty, collapse, seizures or inability to respond needs emergency veterinary care. Do not wait for those signs before calling.
No. Merck states that a minimum toxic dose is not defined for animals. Published observations do not establish a safe home threshold. Give the veterinarian the actual product, strength, amount and time.
- Merck: skeletal muscle relaxant toxicoses
- Pet Poison Helpline: what to remember during a poisoning