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Mirtazapine

Prescription
Noradrenergic/Serotonergic Antidepressant / Appetite Stimulant
Last reviewed 21 Apr 2026 · PetCare.AI Editorial Team
Species
Dog, Cat
Brands
2 available
Interactions
3 documented
Formulations
3

Mechanism of action

Antagonizes central alpha-2 adrenergic autoreceptors (increasing norepinephrine/serotonin release), blocks 5-HT2 and 5-HT3 serotonin receptors (antiemetic, anxiolytic), and has potent H1-antihistamine activity (appetite stimulation and sedation).

At a glance

Class
Noradrenergic/Serotonergic Antidepressant / Appetite Stimulant
Schedule
Prescription
Storage
Tablets at room temperature; Mirataz ointment at room temperature, use within 28 days after opening

Dosing

🐕

Dog

Used for appetite stimulation, antiemetic, and antinausea properties
Dose
1.88–3.75 mg/dog
Route
PO
Frequency
q24h
🐈

Cat

FDA-approved transdermal formulation (Mirataz) for feline weight loss management
Dose
1.88–3.75 mg/cat
Route
PO, Transdermal
Frequency
q48–72h (PO) or q24h (transdermal)

Formulations

💊

Other — 3

Strength
—
Strength
—
Strength
—

Storage

Tablets at room temperature; Mirataz ointment at room temperature, use within 28 days after opening

Safety

Monitoring parameters

Body weight (weekly)Food intakeSedation levelApplication site (transdermal)

Interactions

Major — 2

Fluoxetine
major
Both serotonergic. Fluoxetine inhibits CYP2D6 metabolism of mirtazapine, increasing levels. Serotonin syndrome risk from combined serotonergic activity.
Management: Avoid combination. If appetite stimulation needed with SSRI, reduce mirtazapine dose and monitor for serotonin syndrome.
Selegiline (L-Deprenyl)
major
Mirtazapine (increases serotonin/norepinephrine release) + MAO inhibitor: serotonin syndrome risk.
Management: Avoid. Allow 2-week washout of selegiline before mirtazapine.

Moderate — 1

Tramadol
moderate
Both serotonergic. Additive serotonin effect.
Management: Use with caution. Monitor for serotonin syndrome signs.

Brands

Other markets

Remeron
Mirataz (transdermal feline)

FAQs

Frequently asked questions

›What is Mirtazapine?
Mirtazapine is a noradrenergic/serotonergic antidepressant / appetite stimulant used in pets. Antagonizes central alpha-2 adrenergic autoreceptors (increasing norepinephrine/serotonin release), blocks 5-HT2 and 5-HT3 serotonin receptors (antiemetic, anxiolytic), and has potent H1-antihistamine activity (appetite stimulation and sedation).
›What is Mirtazapine used for in pets?
Mirtazapine is used in veterinary medicine for: Used for appetite stimulation, antiemetic, and antinausea properties; FDA-approved transdermal formulation (Mirataz) for feline weight loss management.
›What is the Mirtazapine dose for dogs?
For dogs, Mirtazapine is typically dosed as follows — Used for appetite stimulation, antiemetic, and antinausea properties: 1.88–3.75 mg/dog PO q24h. Always consult your veterinarian for a dose tailored to your pet's weight, age, and condition.
›What is the Mirtazapine dose for cats?
For cats, Mirtazapine is typically dosed as follows — FDA-approved transdermal formulation (Mirataz) for feline weight loss management: 1.88–3.75 mg/cat PO/Transdermal q48–72h (PO) or q24h (transdermal). Always consult your veterinarian for a dose tailored to your pet's weight, age, and condition.
›Does Mirtazapine need a prescription?
Yes. Mirtazapine is a prescription medication and should only be administered under veterinary supervision.

References

References

Textbooks & handbooks

  • Plumb, D.C. Plumb's Veterinary Drug Handbook. 10th ed., Wiley-Blackwell, 2023.
  • Vail, D.M., Thamm, D.H., & Liptak, J.M. (eds.). Withrow & MacEwen's Small Animal Clinical Oncology. 6th ed., Saunders/Elsevier, 2020.
  • Riviere, J.E., & Papich, M.G. (eds.). Veterinary Pharmacology and Therapeutics. 10th ed., Wiley-Blackwell, 2018.
  • National Research Council. Nutrient Requirements of Dogs and Cats. National Academies Press, Washington DC, 2006.
  • The Merck Veterinary Manual. Merck & Co., Online edition. https://www.merckvetmanual.com/

Clinical guidelines & consensus

  • Fletcher, D.J., Boller, M., Brainard, B.M., et al. "RECOVER Evidence and Knowledge Gap Analysis on Veterinary CPR." Journal of Veterinary Emergency and Critical Care, 2012;22(S1):S102–S131.
  • American Animal Hospital Association. 2018 AAHA Diabetes Management Guidelines for Dogs and Cats. AAHA Press.

Journals & peer-reviewed studies

  • Hogan, D.F., Fox, P.R., Jacob, K., et al. "Secondary prevention of cardiogenic arterial thromboembolism in the cat: The FAT CAT study." Journal of Veterinary Cardiology, 2015;17(Suppl 1):S306–S317.
  • Boswood, A., Häggström, J., Gordon, S.G., et al. "Effect of Pimobendan in Dogs with Preclinical Myxomatous Mitral Valve Disease and Cardiomegaly: The EPIC Study — A Randomized Clinical Trial." Journal of Veterinary Internal Medicine, 2016;30(6):1765–1779.
  • ASPCA Animal Poison Control Center. Toxicology and Poison Management Guidelines. American Society for the Prevention of Cruelty to Animals. https://www.aspca.org/pet-care/animal-poison-control

Regulatory & approvals

  • Central Drugs Standard Control Organisation (CDSCO), Government of India. Veterinary Drug Approval Registry, 1969–2026. Directorate General of Health Services. https://cdsco.gov.in/

Databases

  • Washington State University, College of Veterinary Medicine. Veterinary Clinical Pharmacology Laboratory (VCPL) — MDR1 Multidrug Sensitivity Database. https://vcpl.vetmed.wsu.edu/
Educational reference only
This information is provided for educational purposes and is not a substitute for professional veterinary advice, diagnosis, or treatment. Always consult a qualified veterinarian before administering any medication to your pet. Find a vet near you →