Serotonin Antagonist and Reuptake Inhibitor (SARI) · For Cats

Trazodone dosage reference for cats (Desyrel)

Veterinary references give this medication as a fixed amount per cat, given as a single dose about 1-2 hours before the stressful event, at most once daily, not as a per-kilogram dose, so this guide shows that reference instead of a weight-based calculator. Confirm the product and amount with a veterinarian.

Onset: 1-2 hours
Duration: 6-12 hours
Class: Serotonin Antagonist and Reuptake Inhibitor (SARI)

Weight-based calculator estimate from the references listed on this page. This page has not been independently DVM-reviewed — see our methodology .

This information is for educational purposes only. Always consult your veterinarian before giving medication to your pet. Do not use this calculator for emergencies, overdoses, pregnancy, very young animals, very old animals, pets with liver/kidney disease, or pets taking multiple medications.

Sources and review process

Each medication page lists the references recorded for its data. The calculator math and editorial presentation are maintained by PetDosageChart; a page is independently DVM-reviewed only when a named reviewer byline appears. See our methodology and limitations.

Trazodone (often known by the brand name Desyrel) is a serotonin antagonist and reuptake inhibitor (SARI) used extra-label in cats, most often as a single dose before a vet visit, travel, or another stressful event. It is also used for post-surgical confinement stress and other anxiety under veterinary direction. Understanding the dose, timing, and potential side effects of Trazodone is critical for your cat’s safety and well-being.

No weight-based calculator on this page: Trazodone for cats is prescribed as an amount per cat, not per pound. In the published feline studies, cats received a single 50 mg dose (studied range 50-100 mg) about 1-2 hours before a vet visit. Some veterinarians start lower, at 25 mg, and may choose a smaller amount for small or elderly cats or cats with kidney or liver disease. Give trazodone only as your veterinarian prescribes.

What the source establishes

In a double-blind, placebo-controlled crossover study of 10 client-owned cats, one 50 mg oral dose of trazodone before transport reduced signs of anxiety and made examination easier. Sleepiness was the most common adverse effect. Trazodone was given once, not on a repeating schedule.

This supports a single 50 mg per-cat dose before a stressful event, which is the page's reference amount. It is a small study and does not set the amount for an individual cat.

Stevens et al. (2016): single-dose trazodone before veterinary visits in cats — JAVMA 249:202–207; abstract, procedures and results.

Six laboratory cats received single oral doses of 50, 75 and 100 mg. All doses caused sedation without detected adverse effects on examination or laboratory values. Examinations were done 90 minutes after dosing, and peak sedation after 100 mg came at about 2 hours.

Supports the 50–100 mg per-cat studied range. It is a small single-dose study in laboratory cats and does not establish repeated daily dosing.

Orlando et al. (2016): oral trazodone for sedation in cats, a pilot study — J Feline Med Surg 18:476–482; abstract, methods and results.

Reports that the owners gave one 50 mg tablet at home regardless of weight (7.7–15.2 mg/kg in 3.3–6.5 kg cats). Cats went into the carrier about 1–1.5 hours later, and the examination began about 1.5–2 hours after dosing. One cat became agitated and vocal and one became more fearful on trazodone.

Supports the per-cat amount and the "about 1–2 hours before" timing. It is an appraisal of limited evidence, not a dosing guideline.

Shone (2025): Do cats receiving pre-appointment trazodone experience less stress during veterinary visits? (Veterinary Evidence knowledge summary) — Veterinary Evidence 10(1); summary of the client-owned cat trial.

States that the recommended starting dose in adult cats is 25 mg per cat, titrated to effect up to 100 mg, and that cats reached peak sedation 2 to 2.5 hours after oral administration.

Supports the note that some veterinarians start lower. It gives no specific dose for small or elderly cats or cats with kidney disease; that remains the prescribing veterinarian's judgment.

Clinician's Brief: Trazodone for Dogs & Cats (Sueda and Cho, updated December 2025) — Dosing, cats.

Trazodone Reference Amount for Cats

Cat weight	Reference amount (as a single dose about 1-2 hours before the stressful event, at most once daily)
Any weight	Studied dose: 50 mg per cat (range 50-100 mg), only as prescribed by your veterinarian. A lower vet-chosen starting amount is possible for some cats.

Veterinary references list this amount per cat, not per pound. Give only the amount and schedule your veterinarian prescribes.

If your veterinarian also prescribes gabapentin or another sedative for the same visit, expect the sedation to add up, and follow the clinic’s exact amounts and timing.

By Weight

Desyrel reference by cat weight

Choose a common weight to open its optional reference page. Return to the main guide for the per-cat reference amount.

Common-weight pages are convenience views of the same educational reference, not separate medical recommendations.

How to Give Trazodone to Your Cat

Use only immediate-release generic trazodone tablets, and split them only as your veterinarian directs. Never crush or split an extended-release trazodone product. Give the tablet or tablet piece whole, hidden in a pill pocket or soft treat. For cats that are difficult to pill, ask your vet about compounded liquid or transdermal (ear) formulations. If hiding in food, use a small amount of strong-smelling food like tuna to mask any taste. Give with food to reduce stomach upset. For vet visit anxiety, give the prescribed amount about 1-2 hours before the appointment, or at the time your veterinarian recommends.

It is generally recommended to give Trazodone with food to help reduce stomach upset. It may interact with MAO inhibitors (risk of serotonin syndrome), SSRIs and other serotonergic drugs, CNS depressants (enhanced sedation), and Azole antifungals (increased trazodone levels).

Side Effects and Safety

Common side effects include Sedation and drowsiness, Ataxia (wobbly walking), Decreased appetite, and Gastrointestinal upset. More serious side effects can occur, such as Serotonin syndrome (agitation, tremors, hyperthermia), Severe hypotension, Cardiac arrhythmias, and Priapism (rare).

Cautions · 12

When Desyrel should be used with caution or avoided

Some cats should not take Desyrel, or need a different dose and closer monitoring. Tell your veterinarian about your pet's full health history and every other medication or supplement they take before giving Desyrel.

Concurrent use of MAO inhibitors
Severe liver disease
Known hypersensitivity to trazodone
Use with other serotonergic drugs without veterinary guidance

Interactions · 13

Desyrel drug interactions

Desyrel can interact with other drugs. This list is not complete — always give your veterinarian a full list of your cat's medications and supplements.

MAO inhibitors (risk of serotonin syndrome)

SSRIs and other serotonergic drugs

CNS depressants (enhanced sedation)

Azole antifungals (increased trazodone levels)

Reference Limits · 14

When this reference is not enough

A reference table cannot decide whether a product or treatment is appropriate for an individual animal. Do not rely on it in these situations — talk to your veterinarian instead:

In an emergency, or after accidental ingestion or a suspected overdose
For pregnant or nursing pets
For very young or very old cats
For pets with liver disease, kidney disease, or another chronic illness
For pets taking several medications at once
When you are not sure of your cat's current, accurate weight
For combination products that contain additional active ingredients

Overdose · 15

Suspected overdose: what to do

If you think your cat had too much Desyrel, or swallowed any medication by accident, act right away. Do not wait for symptoms to appear.

Call your veterinarian or the nearest emergency animal hospital.
ASPCA Animal Poison Control Center: (888) 426-4435
Pet Poison Helpline: (855) 764-7661

A consultation fee may apply to the poison hotlines. Have the medication packaging ready, and note how much your pet may have taken and when. Do not try to make your pet vomit unless a veterinarian tells you to.

When to Call the Vet

If your cat experiences any of the following, contact your veterinarian or an emergency clinic immediately:

Extreme lethargy or inability to wake your cat
Tremors, muscle twitching, or agitation (possible serotonin syndrome)
Rapid or irregular heartbeat
Vomiting or diarrhea lasting more than 24 hours
Collapse or severe unsteadiness lasting more than a few hours

Frequently Asked Questions

Frequently Asked · 07

Questions about this medication

How much trazodone can I give my cat?

Trazodone for cats is prescribed as an amount per cat, not per pound. In the published feline studies, cats received a single 50 mg dose (studied range 50-100 mg) about 1-2 hours before a vet visit or other stressful event. Some veterinarians start lower, at 25 mg, and may choose a smaller amount for small or elderly cats or cats with kidney or liver disease. Give only the amount your veterinarian prescribes.

How long does trazodone take to work in cats?

Trazodone typically begins working in cats within 1-2 hours after oral administration. In the feline studies, cats were dosed at home about 1-2 hours before the vet visit, and peak sedation came about 2 hours after a dose. Give it at the time your veterinarian recommends.

Can trazodone be used long-term in cats?

Trazodone can be used both as-needed and as a longer-term treatment for anxiety in cats. When used regularly, your vet may want to perform periodic blood work to monitor liver function. Many cats tolerate it well for extended periods, but it should always be used under veterinary supervision.

Is trazodone safe for cats with kidney disease?

Trazodone is primarily metabolized by the liver, so cats with kidney disease may still be able to take it. However, dose adjustments may be necessary, and your vet should evaluate your cat's overall health before prescribing. Cats with both liver and kidney issues require extra caution.

Can I combine trazodone with gabapentin for my cat?

Yes, trazodone and gabapentin are often used together in cats for enhanced anxiety relief, especially before stressful events like vet visits. This combination is widely recommended by veterinary behaviorists. However, both drugs cause sedation, so doses may need to be reduced when combined. Always consult your vet for the correct combination dosing.

Sources · 09

Sources & references

The structured medication record behind this page names the references below. The links open the publisher or official resource; they do not turn this page into a prescription for an individual animal.

Stevens et al. (2016): single-dose trazodone before veterinary visits in cats
JAVMA 249:202–207; abstract, procedures and results. Supports the specific claim described above; it is not a review of the entire page.
Orlando et al. (2016): oral trazodone for sedation in cats, a pilot study
J Feline Med Surg 18:476–482; abstract, methods and results. Supports the specific claim described above; it is not a review of the entire page.
Shone (2025): Do cats receiving pre-appointment trazodone experience less stress during veterinary visits? (Veterinary Evidence knowledge summary)
Veterinary Evidence 10(1); summary of the client-owned cat trial. Supports the specific claim described above; it is not a review of the entire page.
Clinician's Brief: Trazodone for Dogs & Cats (Sueda and Cho, updated December 2025)
Dosing, cats. Supports the specific claim described above; it is not a review of the entire page.
Plumb's Veterinary Drug Handbook — listed in this medication's source record.
Merck Veterinary Manual — listed in this medication's source record.
DailyMed label search for Trazodone — check current product and formulation labels; some veterinary uses may be off-label.

Specific citations above support the identified claims. Other source names remain record-level references; further claim review is still needed. Read our methodology and limitations.

Transparency · 11

How this page was made

This page's structured medication record includes Plumb's Veterinary Drug Handbook among its source names. This medication is presented with its per-animal reference amount instead of a weight-based calculator. A source record is not the same as an individualized prescription or an independent clinical review.

Sources cited: Plumb's Veterinary Drug Handbook
Merck Veterinary Manual
Calculator formula: No weight-based calculator is shown because veterinary references give this medication as a fixed amount per animal rather than per kilogram. Use the exact amount directed by the veterinarian.
Editorial owner: Prepared and maintained by the PetDosageChart editorial team, a software-led publisher and not a veterinary practice.
DVM review status: Not independently DVM-reviewed. A named reviewer and review date appear here only after a confirmed review.

More on our methodology and editorial process — how we source, calculate, and review cats dosage data.

Safety · 10

More resources

Pet Medication Safety Hub — What's safe, what's dangerous, and emergency signs
How we calculate dosages — Our sources, math, and review process
Printable emergency checklist — One-page reference for your fridge or first aid kit