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Trazodone Dosage Chart for Dogs and Cats

Trazodone is a prescription calming medicine for anxiety in dogs and cats, often used before vet visits, storms or travel, or for rest after surgery. For dogs the Merck Veterinary Manual lists about 2 to 7.5 mg/kg every 8 to 24 hours. This page is a reference only; your vet sets the exact dose.

By Sikander Malik · Updated October 18, 2026 · Sources

Follow your vet’s prescription. Never start, stop or change a dose without your vet.

Trazodone is a prescription medicine, so this page is a reference only, not a dose to give. The table shows the typical prescribed range by weight; your vet calculates the exact amount for your pet.

Reference only, not veterinary advice. Reviewed against the Merck Veterinary Manual trazodone table and the Stevens (2016) and Orlando (2016) cat studies, October 2026. Medical disclaimer.

Tell your vet every medicine your pet takes

Trazodone raises serotonin, so combining it with other serotonergic drugs can cause serotonin syndrome, which is dangerous. That includes fluoxetine, clomipramine, tramadol and selegiline (and other antidepressants or MAO inhibitors). Signs are agitation, tremors, a fast heart rate and fever. Always tell your vet about every medicine and supplement your pet is on.

Trazodone dose for dogs

Trazodone is used for situational anxiety (vet visits, storms, travel, rest after surgery) and for ongoing anxiety. The Merck Veterinary Manual lists 2 to 7.5 mg/kg, every 8 to 24 hours, as needed.

Dog trazodone range by weight
Dog trazodone typical range by weight
WeightTypical range per dose
10 lb10–30 mg
20 lb20–65 mg
40 lb40–135 mg
60 lb55–200 mg
80 lb75–270 mg
100 lb95–340 mg
Approximate, rounded to 5 mg, every 8 to 24 hours. Do not exceed 19.5 mg/kg in any 24 hours (Merck); no fixed milligram-per-dog ceiling is published. Vets usually start at the lower end and adjust. Your vet sets the exact dose.
Source: Merck Veterinary Manual (trazodone 2–7.5 mg/kg PO q8–24h, up to 19.5 mg/kg/24h).

Trazodone dose for cats

For cats, trazodone is mostly used as a one-off for a calmer vet visit or car trip.

Trazodone for cats before a vet visit

A common approach is a single dose of 50 mg per cat, by mouth, about 1 hour before you leave (Stevens et al., 2016), titrated up to 100 mg if needed (Orlando et al., 2016). This is a flat per-cat dose, not by weight. Older cats and cats with liver, kidney or heart disease are often given less, so your vet decides.

Warnings

  • Serotonin syndrome: do not combine with other serotonergic drugs (fluoxetine, clomipramine, tramadol, selegiline, other antidepressants) unless your vet directs it. Watch for agitation, tremors, a racing heart or fever.
  • Sedation and wobbliness (ataxia) are common. Keep your pet off stairs and furniture until it wears off.
  • Do not stop suddenly after long-term use. Your vet tapers it down.
  • Caution with liver, kidney or heart disease. Liver injury and a fast heart rate have been reported, so these pets often need a lower dose and monitoring.
  • Paradoxical reactions: occasionally trazodone causes the opposite effect (restlessness, agitation, increased anxiety). Call your vet if that happens.
  • Priapism: a persistent, painful erection has been reported in male dogs. It is a veterinary emergency, so seek care straight away.

If you think your pet had too much

Call your vet or the ASPCA Animal Poison Control Center at (888) 426-4435 (a consultation fee may apply), or go to your nearest emergency vet. Signs of too much include heavy sedation, severe wobbliness, vomiting, a racing heart, or collapse.

Questions owners ask

How much trazodone can I give my dog?
Only the amount your vet prescribes. For reference, the Merck Veterinary Manual lists 2 to 7.5 mg/kg every 8 to 24 hours, not to exceed 19.5 mg/kg in any 24 hours. On the chart, a 40 lb dog falls around 40 to 135 mg per dose. Vets usually start low and adjust, so never start or change trazodone without your vet.
How much trazodone for a cat?
For a calmer vet visit, cats are often given a single 50 mg dose by mouth about an hour before leaving (Stevens et al., 2016), titrated up to 100 mg if needed (Orlando et al., 2016). It is a flat per-cat dose, not by weight. Older cats and those with liver, kidney or heart disease are often given less, so ask your vet.
How long does trazodone take to work and last?
It usually begins to work within about 1 to 2 hours, which is why the pre-visit dose is given roughly an hour ahead, and effects commonly last several hours. Timing and dose depend on the pet and the situation, so follow your vet’s instructions on when and how often to give it.
Can trazodone be given with other medicines?
Tell your vet about every medicine and supplement first. Trazodone raises serotonin, so combining it with other serotonergic drugs such as fluoxetine, clomipramine, tramadol or selegiline can cause serotonin syndrome, which is dangerous. Your vet will check for interactions before combining anything.
What are the side effects of trazodone?
The most common are sedation and wobbliness, which wear off. Occasionally it causes the opposite effect, with restlessness or agitation. Liver injury, a fast heart rate, and in male dogs a persistent erection (priapism) have been reported; priapism is an emergency. Call your vet if your pet seems unwell.
Can I stop trazodone suddenly?
Not after long-term use. Stopping abruptly can cause problems, so your vet will taper the dose down over time. For occasional situational use, follow your vet’s plan. Always check with your vet before starting, changing or stopping it.

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Sources

Reference only, not veterinary advice. Reviewed against the Merck Veterinary Manual trazodone table and the Stevens (2016) and Orlando (2016) cat studies, October 2026. Medical disclaimer.