Anti-inflammatory
Grapiprant
Confirm dosing with your vet for MDR1-affected dogs
WSU — MDR1 in Dogs (current drug & breed hub)Last verified June 16, 2026
Independent DVM review in progressGrapiprant (Galliprant) is an anti-inflammatory used for osteoarthritis pain. WSU's current MDR1 dog hub lists it among the drugs for which MDR1-affected dogs' dosing should be confirmed with the MDR1 dosing service. Flag your dog's status so the dose is appropriate.
Why MDR1 dogs react to Grapiprant
The MDR1 (ABCB1) gene encodes P-glycoprotein, a pump that limits how much of certain drugs reaches the brain and helps the body excrete them. Dogs with the MDR1 mutation cannot make a fully functional pump, so these drugs accumulate at the blood–brain barrier and cause neurological toxicity.
Signs of toxicity to know
WSU describes severe adverse reactions in affected dogs as tremors, disorientation, blindness, lack of muscle control, and death. If your dog shows these signs after a medication, treat it as an emergency and contact a veterinarian or emergency clinic immediately — this is not a wait-and-see situation, and it is not a question for a website.
Check Grapiprantagainst your dog's breed
Pick your breed to see the verdict in context, with a print-for-vet card.
Pick your dog's breed
The breed sets the baseline likelihood of the MDR1 mutation. Only a DNA test confirms an individual dog's genotype.
This is general information, not veterinary advice for your dog. It does not diagnose or prescribe. Always discuss any medication decision with your veterinarian before acting — they know your dog's full picture, including its MDR1 status if it has been tested. See our disclaimer and how we research.