Mirtazapine

Mirtazapine In Dogs & Cats: Uses, Dosage and Side Effects

Overview

• Tricyclic antidepressant acts on central alpha-2 receptors which leads to increased noradrenaline levels within the brain.
• Also inhibits several types of serotonin receptors and histamine (H1) receptors.

Uses of Mirtazapine

• Appetite stimulation in dogs and cats.
• Efficacy in cats with stable chronic kidney disease has been demonstrated.
• Antiemetic role in conjunction with other drugs, but authorized preparations should be used.
• Anecdotal use beginning to appear concerning its use in the management of social fears in dogs.

Dose of Mirtazapine in Dogs and Cats

Dogs:

• 1.1–1.3 mg/kg p.o. q24h.

Cats:

• 1.9 mg/cat p.o. q48h (can double dose if needed or increase frequency to q24h but not both).

Side Effects of Mirtazapine in Dogs and Cats

• Sedation is common and can be profound.
• Can affect behaviour in many different ways, increased vocalization and interaction with others.
• Has been associated with blood dyscrasias in humans.

Contraindications of Mirtazapine in Dogs and Cats

• Do not use in patients with pre-existing haematological disease.

Some Notes:

• Several interactions are known in humans, principally involving other behaviour-modifying drugs.
• Monitor animals carefully when using mirtazapine, particularly if there is also cardiac, hepatic or renal disease.