Home › Medications › Mirtazapine (Remeron)
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Prescribed to dogs: use only as directed

Also sold as Remeron, Mirataz (veterinary transdermal), Zispin

Vets prescribe this for dogs, so being on it is not a problem in itself. This page is about what happens when a dog gets more than it was meant to have.

DogSafe severity score
4/10

Mirtazapine is prescribed in veterinary practice as an appetite stimulant and anti-nausea drug, including a transdermal version made for animals. It is generally well tolerated, and the usual sign of too much is an exaggerated version of what it is meant to do.

Source-backed guidance. Not individualized veterinary advice.(more)

Compiled from veterinary poison-control and medical references, including the ASPCA Animal Poison Control Center, Pet Poison Helpline, and Merck Veterinary Manual.

Part of Antidepressants and anxiety medication on our medication safety hub.

Part of our guide to Dog Ate Antidepressants, Stimulants or Sleep Medication.

Got the amount wrong, or your dog reached the container?

Call the practice that prescribed it: they know the dose your dog is on, which is what decides whether this matters. Out of hours, either line below is open.

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.

Signs so far
Before you 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 Mirtazapine (Remeron) needs caution

Mirtazapine increases appetite and reduces nausea, which is why vets reach for it in dogs and cats that have stopped eating. Too much produces sedation, wobbliness, vocalizing, restlessness and a fast heart rate, and it can raise serotonin enough to matter when combined with an SSRI or trazodone. The human tablets come in strengths well above a typical veterinary dose, and there is an orally-disintegrating version that a dog can take a lot of very quickly.

Part of the Ondansetron guide

For related dog-safety questions and product-by-product answers, see the complete ondansetron guide.

Signs to watch for

Most commonly vomiting, diarrhea, drooling, or mild sedation; less commonly unsteadiness or weakness after a large amount

Related items

Check the exact item or ingredient before assuming two similar exposures carry the same risk.

What to do next

Count the remaining tablets against what the prescription should have left, note the strength and the time, and call your vet's line with that number.

🚨Step-by-step: what to do in the first 10 minutes →
Animal poison control

A closer look at mirtazapine (remeron)

Mirtazapine increases appetite and reduces nausea, which is why vets reach for it in dogs and cats that have stopped eating. Too much produces sedation, wobbliness, vocalizing, restlessness and a fast heart rate, and it can raise serotonin enough to matter when combined with an SSRI or trazodone. The human tablets come in strengths well above a typical veterinary dose, and there is an orally-disintegrating version that a dog can take a lot of very quickly. The details below use the specific facts for this exposure, rather than treating it like every other medication question.

1. Start with the exact exposure

For a closely related comparison, read Clomipramine (Clomicalm). Your vet sets the dose, and it is specific to your dog's weight and condition. Nothing on this page is a dose to give. What matters after an accidental exposure is how much more than the prescribed amount was taken.

2. Use the facts to decide whether to monitor or call

Another helpful reference is Ondansetron. For a single extra dose of your dog's own prescription with no signs, call your vet's line for advice before deciding anything. Do not double up a later dose to compensate, and do not stop a prescribed course on your own. Call if a whole container may have been emptied, if the amount is uncertain, if your dog is vomiting repeatedly or seems unsteady, or if this is a human product rather than your dog's prescription.

3. If the details are uncertain

Follow the first 10 minutes guide. Count the remaining tablets against what the prescription should have left, note the strength and the time, and call your vet's line with that number.

FAQ

How much Mirtazapine (Remeron) is dangerous?

Your vet sets the dose, and it is specific to your dog's weight and condition. Nothing on this page is a dose to give. What matters after an accidental exposure is how much more than the prescribed amount was taken.

Can I treat this at home?

For a single extra dose of your dog's own prescription with no signs, call your vet's line for advice before deciding anything. Do not double up a later dose to compensate, and do not stop a prescribed course on your own.

When should I call the vet?

Call if a whole container may have been emptied, if the amount is uncertain, if your dog is vomiting repeatedly or seems unsteady, or if this is a human product rather than your dog's prescription.

SourcesUpdated August 10, 2026
  • Merck Veterinary Manual — toxicoses in animals from human antidepressants, anxiolytics and sleep aids
  • ASPCA Animal Poison Control Center — human medications
  • Pet Poison Helpline — top 10 human medications poisonous to pets
Read DogSafe's sources and review policy →
Compiled from veterinary poison-control and medical reference sources, including the ASPCA Animal Poison Control Center, the Pet Poison Helpline, and the Merck Veterinary Manual. This is general educational information, not a diagnosis or a substitute for examination by your veterinarian. DogSafe's severity ratings are our own assessment, calculated from published guidance and your dog's weight. In an emergency, call ASPCA Animal Poison Control at 888-426-4435 or the Pet Poison Helpline at 855-764-7661.