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If your dog tests positive

A positive result is a plan, not a panic

If your dog has the MDR1 mutation, here is exactly what to do — calmly, in order. None of it is urgent unless your dog has actually had an affected drug; most of it is simple record-keeping that protects your dog for life.

  1. 1. Print a vet card

    Make a one-page card that says your dog is MDR1-positive and lists the drugs to flag. Keep a copy in your dog's file, your wallet, and your phone. The drug checker can print this for any drug you look up.

  2. 2. Update your dog's permanent records

    Ask your regular vet to add 'MDR1 mutant' (and the genotype, if you have it) to your dog's permanent chart, so it travels with every visit — including ones you don't plan.

  3. 3. Flag the drug list at every appointment

    Mention your dog's MDR1 status at the start of every appointment, before any drug is chosen. It takes ten seconds and it's the single most useful thing you can do.

  4. 4. Know the pharmacy notes

    Some MDR1 drugs have safe alternatives or reduced doses your vet can prescribe instead. This is a conversation for your veterinarian, who chooses the substitute — not a swap to make on your own.

  5. 5. Have an emergency-vet protocol

    If an avoid-drug is ever given by accident, or your dog shows signs like tremors, disorientation, blindness, lack of muscle control, and death, treat it as an emergency: call a veterinarian or emergency clinic immediately and tell them your dog is MDR1-positive. Don't wait to see if it passes.

  6. 6. Then — relax

    An MDR1-positive dog can live an entirely normal life. The mutation affects a specific, knowable list of drugs at specific doses. Once you and your vet know the list, the risk is managed. This is a manageable risk profile, not a death sentence.

The short list to put on your vet card

Avoid entirely

Dose matters — confirm with vet

This is the short list. Sedatives and chemotherapy agents also need reduced doses — see the full drug list — but those are always chosen by your vet, so the card above covers the drugs you most need to flag yourself.

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.