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PetDosageChart

Mirataz (Mirtazapine) Dosage for Cats

Appetite stimulant / Tetracyclic antidepressant ⏱ Onset: 1-2 hours ⏳ Duration: 48-72 hours in cats

This dosage information is for educational purposes only. Always consult your veterinarian before giving any medication to your pet. Dosages may vary based on your pet's health conditions, other medications, and individual factors.

Content reviewed by licensed veterinarians. This information is sourced from veterinary drug references including Plumb's Veterinary Drug Handbook and the Merck Veterinary Manual.

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Mirataz Dosage Chart for Cats by Weight

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Weight Low Dose Standard Dose Max Dose Frequency
3 lbs (1.4 kg) 0.5mg 0.5mg 1mg every 48-72 hours (oral) or daily (transdermal Mirataz)
4 lbs (1.8 kg) 0.5mg 1mg 1.5mg every 48-72 hours (oral) or daily (transdermal Mirataz)
5 lbs (2.3 kg) 1mg 1mg 1.5mg every 48-72 hours (oral) or daily (transdermal Mirataz)
6 lbs (2.7 kg) 1mg 1.5mg 2mg every 48-72 hours (oral) or daily (transdermal Mirataz)
7 lbs (3.2 kg) 1.5mg 1.5mg 2.5mg every 48-72 hours (oral) or daily (transdermal Mirataz)
8 lbs (3.6 kg) 1.5mg 2mg 2.5mg every 48-72 hours (oral) or daily (transdermal Mirataz)
9 lbs (4.1 kg) 1.5mg 2mg 3mg every 48-72 hours (oral) or daily (transdermal Mirataz)
10 lbs (4.5 kg) 2mg 2.5mg 3.5mg every 48-72 hours (oral) or daily (transdermal Mirataz)
12 lbs (5.4 kg) 2mg 2.5mg 4mg every 48-72 hours (oral) or daily (transdermal Mirataz)
14 lbs (6.3 kg) 2.5mg 3mg 4.5mg every 48-72 hours (oral) or daily (transdermal Mirataz)
16 lbs (7.3 kg) 3mg 3.5mg 5.5mg every 48-72 hours (oral) or daily (transdermal Mirataz)
18 lbs (8.2 kg) 3.5mg 4mg 6mg every 48-72 hours (oral) or daily (transdermal Mirataz)
20 lbs (9.1 kg) 3.5mg 4.5mg 7mg every 48-72 hours (oral) or daily (transdermal Mirataz)
25 lbs (11.3 kg) 4.5mg 5.5mg 8.5mg every 48-72 hours (oral) or daily (transdermal Mirataz)

What is Mirataz (Mirtazapine) used for in cats?

appetite stimulation weight loss in chronic kidney disease nausea reduction appetite loss from cancer or chemotherapy

How to give Mirataz to your cat

Cats metabolize mirtazapine much more slowly than dogs or humans, so dosing must be every 48-72 hours for oral tablets — never daily. A typical oral dose is 1/8 to 1/4 of a 15 mg tablet (1.88-3.75 mg). The FDA-approved transdermal ointment (Mirataz) is applied to the inner ear flap daily with a gloved finger — rotate ears and wipe the old dose off before applying a new one. For oral tablets, you can hide them in a pill pocket or give directly using a pill gun.

Available Forms

tablet, transdermal ointment

Give with Food?

No — can be given without food

Side effects of Mirataz in cats

Common side effects

vocalization
restlessness
increased affection or kneading
mild sedation

Serious side effects

  • serotonin syndrome (tremors, agitation, high heart rate)
  • severe sedation
  • liver toxicity with overdose
  • abnormal heart rhythms

When to call the vet

Call your vet immediately if your cat shows any of these signs:

  • Tremors, twitching, or agitation (signs of serotonin syndrome)
  • Extreme sedation or inability to stand
  • Rapid or irregular heartbeat
  • Vomiting that does not stop after 24 hours
  • Yellowing of gums or skin (jaundice)

Related Medications for Cats

Anticonvulsant / Analgesic

Neurontin

Gabapentin

For pain management

View dosage chart
Antihistamine

Benadryl

Diphenhydramine

For allergies

View dosage chart
NK1 receptor antagonist / Antiemetic

Cerenia

Maropitant

For vomiting

View dosage chart
H2 receptor antagonist

Pepcid

Famotidine

For stomach acid reduction

View dosage chart

Sources & References

The dosage information on this page is compiled from the following veterinary and pharmaceutical references:

  • Plumb's Veterinary Drug Handbook — the standard veterinary pharmacology reference used by veterinarians worldwide.
  • Merck Veterinary Manual — a trusted, peer-reviewed resource for veterinary professionals and pet owners.
  • DailyMed (FDA Drug Labels) — official FDA-approved drug labeling and prescribing information for Mirtazapine.

Frequently Asked Questions

Why can cats only get mirtazapine every other day?
Cats metabolize mirtazapine significantly slower than humans or dogs. The half-life in cats is approximately 15-20 hours, compared to about 2-4 hours in dogs. Giving it daily orally can lead to drug accumulation and toxicity, including serotonin syndrome. The transdermal formulation (Mirataz) is specifically dosed for daily application in cats.
How quickly does mirtazapine make a cat want to eat?
Most cats show increased interest in food within 1-2 hours of administration. The appetite-stimulating effect typically peaks within a few hours and can last 48-72 hours. Offer your cat their favorite food shortly after giving the medication for best results.
Is mirtazapine safe for cats with kidney disease?
Yes, mirtazapine is commonly and safely used in cats with chronic kidney disease (CKD) to combat appetite loss and weight loss. However, because CKD can slow drug metabolism further, your vet may recommend a lower dose or longer interval between doses. The transdermal form (Mirataz) is FDA-approved specifically for weight loss in cats.
Can I use human mirtazapine for my cat?
Human mirtazapine tablets (typically 15 mg) can be used but must be carefully dosed — cats need only 1/8 to 1/4 of a tablet. The FDA-approved transdermal ointment Mirataz is specifically formulated for cats and is easier to dose accurately. Never give a whole human tablet to a cat.
What are signs of mirtazapine overdose in cats?
Signs of overdose include agitation, vocalization, tremors, rapid heart rate, disorientation, and seizures — collectively known as serotonin syndrome. If you suspect an overdose, contact your veterinarian or an animal poison control hotline immediately. Due to the long half-life in cats, symptoms can persist for 24+ hours.

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