Description

Mirtazapine is a tetracyclic antidepressant used for Major Depressive Disorder in humans; however, this medication is most often used in animals to stimulate appetite and prevent vomiting.

Used to help treat cats and dogs with conditions that cause nausea, vomiting, and poor appetite (e.g., chemotherapy-induced symptoms, chronic kidney disease).
Can also be prescribed to help manage anxiety-related behavioral issues in dogs
Do not use this medication within at least 2 weeks of a monoamine oxidase inhibitor (MAOI), including amitraz, an ingredient in certain flea and tick collars.
May be prescribed for other animal species; please consult your veterinarian.
While this drug does not have an FDA-approved indication for all animal uses, it is commonly accepted for veterinarians to prescribe this medication for use in animals.

Medications can play a significant role in comprehensive behavior modification therapy. Please follow your pet’s individual treatment plan, which may include a combination of medications and behavioral modification strategies, as recommended by your veterinarian or animal behaviorist.

*Please note: this is a generic medication. Product packaging and appearance, including size, color, and shape, may differ from the description or images provided and are subject to manufacturer availability.

Sourced directly from the manufacturer or their approved distributor. Guaranteed genuine product backed by the manufacturer.

For

Dogs and Cats

Active ingredient(s)

Mirtazapine

Common brand names

Remeron

Drug class

Tetracyclic antidepressant

Product strength & size

This product may be available in multiple strengths and/or sizes; please select the appropriate option for your pet as recommended by your veterinarian.

For current availability, please refer to the product selection above.

Usage

Mirtazapine tablets should be given orally as directed by your veterinarian.

Do not discontinue this medication abruptly. Please consult your veterinarian before making any changes or discontinuing the prescribed dosing schedule.

This medication can be given with or without food. If your pet vomits or appears unwell after receiving a dose on an empty stomach, give future doses with food or a small treat. If vomiting continues, contact your veterinarian.

Missed doses

Administer the dose as soon as possible. If it is almost time for the next dose, skip the missed dose and continue with the regular schedule. Do not give two doses at once.

Storage

Store in a cool, dry place at a controlled room temperature (77°F, excursions permitted between 59 and 86°F). Keep in a tight, light-resistant container and out of the reach of children and pets. Store away from heat and direct sunlight. Do not store in the bathroom, near the kitchen sink, or in damp places. The medicine may break down if exposed to heat or moisture.

Side effects

This medication is generally well tolerated in dogs and cats. The most common side effects are drowsiness, lowered energy level, increased vocalization, mild agitation/restlessness, vomiting, increased salivation/drooling, and mild muscle tremors/shaking.

Other possible side effects include (but may not be limited to): rapid, shallow breathing;elevated heart rate; dry mouth or panting; urinary retention; and constipation.

Contact your veterinarian immediately if your pet displays decreased coordination while walking or behavioral changes, including hyperactivity, hyperexcitability, or excessive agitation.

Notify your veterinarian if your pet experiences any of the effects described above, or if you notice any other side effects that are persistent or troublesome.

If you notice anything unusual, please consult your veterinarian.

Precautions

Do NOT discontinue this medication abruptly. Please consult your veterinarian before making any changes to the prescribed dosing schedule.

Because this medication should NOT be used within at least 2 weeks of any monoamine oxidase inhibitor (e.g., selegiline, amitraz), it is NOT compatible with flea and tick collars that contain amitraz as an active ingredient. If your pet is currently using one of these collars, consult your veterinarian before starting this medication.

Use with caution in animals with a history of epilepsy/seizures; low blood pressure; liver or kidney disease; electrolyte imbalances, abnormal heart rhythms, or heart disease; glaucoma or dry eye syndrome; diabetes; blood disorders, including low platelet or white blood cell counts; and gastrointestinal or urinary blockage. This medication can worsen constipation and urinary difficulty/retention.

Safe use of this medication has not been established in breeding, pregnant, or lactating animals.

Do not administer to animals with a known history or suspected allergy/hypersensitivity to this medication or any of its ingredients. Allergic reactions to medications may occur. Be sure to inform Vetsource and your veterinarian if your pet has any known drug sensitivities or allergies.

If your pet displays symptoms of an allergic reaction, discontinue therapy and call your veterinarian immediately or seek emergency veterinary attention. Symptoms may include (but are not limited to): swollen lips, tongue, face, or airways, difficulty breathing, agitation, profuse salivation, and widespread hives or itching.

Drug and food interactions

The following drugs* may have potential interactions with this medication: acepromazine, amitraz, antihistamines (e.g., diphenhydramine, hydroxyzine), azole antifungals (e.g., itraconazole, ketoconazole), beta blockers (e.g., atenolol, sotalol), blood pressure medications (e.g., amlodipine, enalapril, telmisartan), clonidine, CNS depressant drugs (e.g., dexmedetomidine, gabapentin, methocarbamol, trazodone), dexamethasone, diuretics (e.g., furosemide), estriol, metoclopramide, ondansetron, opioids, phenobarbital, selegiline, SSRIs (e.g., fluoxetine, sertraline), tramadol, tricyclic antidepressants (e.g., amitriptyline, clomipramine), and warfarin.

*NOTE: this may not be a comprehensive list. Contact your veterinarian if your pet experiences any unusual reactions when different medications are given together.

Please ensure your veterinarian is aware of all medications and supplements that your pet is currently receiving. Your veterinarian may prescribe multiple medications, even if a potential drug interaction may occur. In these instances, your veterinarian may adjust the dosages or monitor your pet more closely.

Adverse reactions

If you are concerned that your pet has experienced an adverse reaction to this medication, please contact Vetsource Pet Owner Care at 877-738-4443.

Last revised: 5/21/2025

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