Mirtazapine

Updated on September 10, 2024

Mirtazapine, is an antidepressant in humans, that may be used in dogs and cats for appetite stimulation and antiemetic properties

Mirtazapine

Summary

Used For: Appetite stimulant, anti-nausea medication

Brands: Remeron®

Species: Cats and dogs

Drug type: Antidepressant

Prescription required: Yes

Pregnancy and lactation: Use with caution in pregnant and lactating animals due to unknown effects

Side effects: Sedation, low blood pressure, increased heart rate, behavioral changes, increased vocalization

General description

Mirtazepine is an antidepressant medication most often used in human medicine. In veterinary medicine, it is primarily used in dogs and cats to increase appetite and improve signs of nausea associated with a variety of health conditions, including kidney disease.

Uses

Appetite stimulant, anti-nausea medication. Used extra-label in veterinary medicine

How it works

Mirtazapine causes increases in serum norepinephrine and blocks serotonin receptors, which may account for appetite stimulation and anti-nausea properties.

Dosage

Dogs: 3.75-30 milligrams by mouth once daily, depending on the dog’s body weight Cats: 1.88 milligrams per cat by mouth every 24-48 hours.

Forms

Mirtazepine tablets for oral use available in 7.5 milligram, 15 milligram, 30 milligram, & 45 milligram sizes; mirtazepine orally disintegrating tablets available in 15 milligram, 30 milligram, & 45 milligram sizes **(Note: some generic orally disintegrating tablets contain xylitol, which is toxic to dogs.)**

Storage information & handling

Store in a childproof container at room temperature, out of the reach of pets and children.

What results can I expect?

Increased in appetite and decrease in vomiting

Missed Dosage

If a dose is missed, give the missed dose as soon as possible. If it is almost time for the next dose, skip the missed dose and give the next dose at the regularly scheduled time. Do not give two doses at once.

Overdose / acute toxicity

If an overdose is known or suspected, seek veterinary attention immediately. Signs of an overdose can include tremors, vocalization, agitation, panting, lethargy, vomiting, increased heart rate, and ataxia (abnormal, wobbly gait).

Side effects

*Sedation *Behavior changes *Vocalization *Hypotension (low blood pressure) *Tachycardia (increased heart rate) *Elevated liver enzymes in some cats

Contraindications

*Previous sensitivity *Use with caution with pre-existing heart disease or blood pressure changes *Use with caution in patients with changes in red or white blood cells, or platelets

Drug interactions

Clonidine, cyproheptadine, diazepam (and other benzodiazepines), linezolid, tramadol, amitraz, selegiline, and fluvoxamine can all interact with mirtazepine. Always discuss any medication or supplements with your veterinarian due to potential drug interactions.

Precaution

Use with caution in patients with pre-existing heart disease or blood pressure changes, as well as changes in red or white blood cells, or platelets. Use with caution in pregnant or lactating animals.

Sources

Plumb’s Veterinary Drug Handbook
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Disclaimer

The information contained on this page is for educational purposes only. This medication should only be given under the advice of a veterinarian who has examined your pet under the laws applicable to your state of residence.