Trazodone

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

Overview

• Trazodone is an atypical antidepressant with mixed serotonergic agonistic (5HT1A) and antagonistic actions (other 5HT receptor sites).

Uses of Trazodone

• Effective for chronic anxiety in dogs not responding to other medications, but should be combined with behaviour modification.
• Caution is needed in dogs with renal disease; monitor carefully.
• Lower risk in dogs with cardiac disease compared to tricyclic antidepressants like amitriptyline.
• Helpful in reducing anxiety during hospitalization and postoperative confinement in dogs.
• Suitable for short-term anxiety management in cats, such as travel or examination anxiety.

Dose of Trazodone in Dogs and Cats

Dogs:

• For management of short-term anxiety associated with hospitalization: 4 mg/kg p.o. q12h titrated upwards to 10–12 mg/kg as needed to a maximum of 300 mg per dose.
• For chronic anxiety issues: initial dose for 5–10 kg, 25 mg p.o. q24h; 11–20 kg, 50 mg p.o. q24h; >21 kg, 100 mg p.o. q24h.
• Doses may be titrated upwards every 10–14 days to a maximum of double the recommended initial dose.
• Doses for dogs >40 kg may be titrated to a maximum of 300 mg p.o. q24h.
• The dose may need to be increased if used long-term as tolerance over time is common.
• Lower-end doses may be used adjunctively with SSRIs (e.g. fluoxetine) but not MAOIs, but the risk of serotonin syndrome should be recognized.

Cats:

• 50–100 mg/cat p.o. q24h; for short-term use only; 50 mg/cat administered 1 hour before travel to address transport and examination-related anxiety.

Side Effects of Trazodone in Dogs and Cats

• Sedation, vomiting, excitability and dry mouth.
• Third eyelid protrusion is described in some cats.

Contraindications of Trazodone in Dogs and Cats

• Glaucoma, history of seizures or urinary retention and severe liver disease.

Some Notes:

• Avoid use with monoamine oxidase inhibitors or drugs metabolized by cytochrome P450 2D6, such as chlorphenamine and cimetidine.
• Risk of serotonin syndrome if combined with other serotonergic substances, but adjunctive therapy may be considered in some cases.
• Ketoconazole inhibits trazodone breakdown, leading to increased blood levels, while carbamazepine has the opposite effect.
• Itraconazole might have a similar effect, though clinical evidence is lacking.