Trazodone: veterinary dose and monograph

At a glance

Drug class

Sedative / anaesthetic

Also known as

Desyrel, Oleptro

Species with doses

Dogs and Cats

General dose range

2–10 mg/kg PO q8–24h — check the species tables for the indication

Routes

PO

Last reviewed

1 October 2026

Indications

• Pre-visit anxiety (dogs and cats)
• Post-operative confinement (orthopaedic recovery)
• Storm / fireworks phobia
• Travel anxiety
• Adjunct to behaviour modification for generalised anxiety
• Hospitalisation stress in cats

Trazodone dose by species

Doses are per administration unless stated. mg/kg doses scale with body weight; per-animal, per-quarter and infusion-rate doses are shown as the reference writes them.

Dogs

• Situational anxiety (pre-visit, fireworks): Plumb’s p.1140 (Neilson 2010): 2–5 mg/kg about an hour before anticipated anxiety, adjusting upward as needed (max 14 mg/kg/day). Papich 5e: typical starting dose 5–8 mg/kg, given at least 1 h before the event. Trial the dose at home first.
• Daily adjunctive anxiety therapy: Plumb’s p.1140: 1 mg/kg PO q12h for 7 days, then up to 3 mg/kg q12h (Frank 2010); 1–4.8 mg/kg PO twice daily, titrated weekly (Virga 2010). Papich 5e: typical starting dose 5–8 mg/kg q12h (q8–24h). Start at half the target dose for 3 days to limit GI signs.

Cats

• Pre-visit / hospitalisation: 50 mg/cat (single tablet) PO. Combine with gabapentin 50–100 mg for difficult cats. Papich 5e p926: 50–100 mg/cat PO, 50 mg usually sufficient; peak effect 2–2.5 h.

Contraindications

Hypersensitivity. Concurrent MAO-I (serotonin syndrome). Severe hepatic / renal disease (reduce dose). Concurrent serotonergic drugs (SSRI, TCA, tramadol) at high cumulative doses.

Species-specific warnings

Dogs: TEST DOSE at home first — 5–10% develop paradoxical agitation. Otherwise extremely safe. 4–10 mg/kg PO 60–90 min pre-event.

Cats: 50 mg/cat PO 90 min pre-visit. Combine with gabapentin 50–100 mg for difficult cats — synergistic.

Adverse effects

• Mild sedation (intended effect)
• Ataxia at higher doses
• GI upset (vomiting, diarrhoea) — uncommon
• Paradoxical agitation in 5–10% of dogs (use lower dose or switch)
• Priapism (humans, rare in vet) — limited reports
• Hypotension (mild)
• Cats: vocalisation, salivation at higher doses

Drug interactions

• MAO-I: CONTRAINDICATED — serotonin syndrome
• SSRI (fluoxetine, sertraline): cumulative serotonergic effect — caution
• TCA (amitriptyline, clomipramine): additive serotonergic effect
• Tramadol: serotonin syndrome risk at high cumulative doses
• CYP3A4 inhibitors (ketoconazole, ciprofloxacin): increase trazodone levels
• CYP3A4 inducers (phenobarbital): decrease trazodone levels
• CNS depressants: additive sedation
• Antihypertensives: additive hypotension

Pregnancy and lactation

Crosses placenta. FDA Category C (human). Limited vet data. Avoid in pregnancy unless clinically essential.

Monitoring

• Sedation depth — test dose at home before relying on for event
• Paradoxical agitation — switch to alternative if observed
• Concurrent SSRI / TCA — serotonin syndrome risk
• Hypotension in cardiac / hypovolaemic patients
• Cats: vocalisation / hypersalivation at high doses

Toxicity and overdose

Wide therapeutic margin. Overdose: profound sedation, hypotension, ataxia. Serotonin syndrome unlikely without co-administered serotonergic drugs. Priapism reported in human males (very rare in dogs). Cats: hyper-salivation, vocalisation, occasional aggression at high doses.

Management: Supportive — most overdoses self-limiting. Activated charcoal if recent ingestion. IV fluids for hypotension. Serotonin syndrome: cyproheptadine 1.1 mg/kg PO q6h, active cooling. Most patients recover within 12–24 h.

Clinical pearls

• Dogs pre-visit: 4–10 mg/kg PO 60–90 min before vet visit — test dose at home first
• Dogs post-op confinement: 2–5 mg/kg PO q8–12h × 7–14 days for kennel rest after orthopaedic surgery
• Cats pre-visit: 50 mg/cat PO 90 min before transport — combine with gabapentin 50–100 mg for extra effect
• Combine with gabapentin for synergistic anxiolysis — common protocol: trazodone + gabapentin 1.5 h pre-visit
• Lower doses give anxiolysis without sedation; higher doses give frank sedation — titrate to need
• Paradoxical agitation in ~5–10% of dogs — switch to gabapentin or alprazolam alternative
• Avoid with fluoxetine + tramadol — serotonin syndrome risk
• Replaces acepromazine in most modern vet practices — better tolerated, no Boxer / stallion issues

Mechanism of action

Serotonin antagonist and reuptake inhibitor (SARI). Primary action: 5-HT2A receptor antagonism + serotonin reuptake inhibition (weak). Also weak alpha-1 adrenergic blockade (contributes to sedation / hypotension). Effects: anxiolysis, mild sedation, sleep modulation. Not a classical SSRI — does NOT primarily increase synaptic serotonin.

Formulations and products

• Trazodone 50 / 100 / 150 / 300 mg tablet (human)
• Desyrel — 50 / 100 / 150 / 300 mg, Tablet (human-label)

Storage

Tablets: 15–25 °C, dry, protected from light.

Before you use this dose

Reference doses for veterinary professionals. Confirm the dose against the product label, the patient’s condition, current guidance and local regulations before use; the attending veterinarian remains responsible for every clinical decision.

Other sedatives and anaesthetics

• Romifidine
• Sevoflurane
• Thiopental Sodium
• Tiletamine–Zolazepam
• Xylazine

Frequently asked questions