Is Metformin (Glucophage) Safe for Dogs?
Why it’s a problem
Metformin mainly irritates the digestive tract in dogs, and small exposures have been reported to cause vomiting and diarrhea. Very large ingestions can drive blood sugar down and, rarely, contribute to lactic acidosis. Risk scales with the size of the dog and the number of tablets eaten.
How to keep your pet safe
Keep metformin out of reach, and be careful with pill organizers, which dogs can chew open. A dog with diabetes or weight issues needs a veterinary plan, not human diabetes drugs.
Warning signs to watch for
Vomiting, diarrhea, drooling, belly discomfort, lethargy; large ingestions: weakness, wobbliness, trembling from low blood sugar, collapse.
When to call the vet
Call your veterinarian or a pet poison hotline after any exposure — small dogs and large exposures need closer monitoring. Report how many tablets may have been eaten so the risk can be judged.
Common questions
My dog ate my metformin — will it kill him?
A single tablet in a larger dog usually causes stomach upset, but several tablets can cause low blood sugar, and small dogs are at higher risk. Call your vet or a poison hotline with the amount and your dog’s weight.
Can metformin help my overweight dog?
Only a veterinarian should decide whether any drug is appropriate for a pet. Never self-dose a dog with human diabetes medication.
More medications hazards for dogs
This page is general educational information, not a substitute for professional veterinary advice. Every pet is different — if your animal ate or touched something concerning, contact your veterinarian or a pet poison hotline right away. In the US: Pet Poison Helpline (855) 764-7661, ASPCA Animal Poison Control (888) 426-4435 (fees may apply).