Anaesthesia is safe for MDR1-affected dogs. There is no class of dog that “can't be put under.” What matters is that the anaesthetic protocol accounts for the mutation — and that's a routine adjustment your veterinary team can make easily, as long as they know.
The two drugs to flag
Two drugs commonly used around anaesthesia appear on WSU's MDR1 list as needing reduced doses in affected dogs:
- Acepromazine — a tranquiliser often used as a pre-anaesthetic sedative or to calm an anxious dog. WSU lists it among the drugs where affected dogs are more sensitive and should receive reduced doses.
- Butorphanol — an opioid used for pain control and as a pre-anaesthetic. WSU lists it in the same group: reduced doses for affected dogs.
WSU's guidance for these drugs is that dogs that are mutant/mutant or mutant/normal should receive reduced doses to avoid heightened or prolonged effects. This isn't an instruction to avoid the drugs — it's an instruction to dose them with the mutation in mind, which is precisely the sort of adjustment a veterinary anaesthetist makes routinely.
What to do before the procedure
The single most useful thing you can do is tell the surgical team your dog is MDR1-positive before the day of the procedure, not as they're wheeling your dog back. Ideally:
- Mention it when you book, and again at check-in.
- Bring the vet card from our positive-dog protocol if you have it — a printed reminder is hard to overlook.
- If your dog has a genotype result (mutant/mutant vs mutant/normal), share that too — it helps the team calibrate.
If you don't know your dog's status
If your dog is an at-risk breed and you haven't tested, a scheduled procedure is a very common reason owners decide to test — because the result changes the anaesthetic plan. If there isn't time before the procedure, tell your vet your dog is an untested at-risk breed; many teams will simply treat the dog as potentially affected and dose conservatively, which is the cautious and reasonable approach. See how to test your dog for the routes available.
The bottom line
Don't cancel the surgery and don't panic. An MDR1-affected dog can be anaesthetised safely every day of the week. The whole task is to make sure the team knows, so they can reduce the doses of acepromazine and butorphanol where they're used. Flag it, bring the card, and let your veterinary team do what they do.