Serotonin Antagonist and Reuptake Inhibitor (SARI) · For Cats

Trazodone dosage reference for cats (Desyrel)

This page's standard weight-based reference is 3.5 mg per kg (1.59 mg per lb), with As needed or every 8-24 hours recorded as the reference frequency. Use the calculator to see the arithmetic for your cat's weight, then confirm the indication, product, and actual dose 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.

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 brand names such as Desyrel and Oleptro) is a serotonin antagonist and reuptake inhibitor (SARI) commonly used in veterinary medicine for Anxiety and fear reduction, Pre-veterinary visit sedation, Post-surgical confinement stress, Travel anxiety, and Inter-cat aggression. Understanding the correct dosage, administration, and potential side effects of Trazodone is critical for your cat’s safety and well-being.

A typical Trazodone dose for cats is around 3.5 mg/kg As needed or every 8-24 hours, within a usual range of 2-5 mg/kg. Available forms include Tablet, Compounded liquid, and Compounded transdermal.

Calculator Warning: Use this only as an educational estimate. Your veterinarian may prescribe a different dose based on your pet’s condition, age, weight, other medications, and medical history.

Trazodone Dosage Calculator for Cats

Enter your cat’s weight below to estimate the Trazodone dose from the 3.5 mg/kg guideline. Your veterinarian may adjust it for your cat’s age, condition, and other medications, so treat the result as an educational starting point, not a prescription.

Dosage Calculator · 01

Enter your cat's weight

Quick Dosage Chart

Typical Trazodone amounts for common cat weights, for quick reference:

Dosage Chart · 02

Desyrel weight-based reference chart for cats

Scroll sideways to see full table

Weight	Lower Reference	Standard Reference	Upper Reference	Frequency
3 lbs (1.4 kg)	2.8 mg	4.9 mg	7.0 mg	As needed or every 8-24 hours
4 lbs (1.8 kg)	3.6 mg	6.3 mg	9.0 mg	As needed or every 8-24 hours
5 lbs (2.3 kg)	4.6 mg	8.0 mg	11.5 mg	As needed or every 8-24 hours
6 lbs (2.7 kg)	5.4 mg	9.5 mg	13.5 mg	As needed or every 8-24 hours
7 lbs (3.2 kg)	6.4 mg	11.2 mg	16.0 mg	As needed or every 8-24 hours
8 lbs (3.6 kg)	7.2 mg	12.6 mg	18.0 mg	As needed or every 8-24 hours
9 lbs (4.1 kg)	8.2 mg	14.3 mg	20.5 mg	As needed or every 8-24 hours
10 lbs (4.5 kg)	9.0 mg	15.8 mg	22.5 mg	As needed or every 8-24 hours
12 lbs (5.4 kg)	10.8 mg	18.9 mg	27.0 mg	As needed or every 8-24 hours
14 lbs (6.3 kg)	12.6 mg	22.1 mg	31.5 mg	As needed or every 8-24 hours
16 lbs (7.3 kg)	14.6 mg	25.6 mg	36.5 mg	As needed or every 8-24 hours
18 lbs (8.2 kg)	16.4 mg	28.7 mg	41.0 mg (50mg tablet)	As needed or every 8-24 hours
20 lbs (9.1 kg)	18.2 mg	31.8 mg	45.5 mg (50mg tablet)	As needed or every 8-24 hours
25 lbs (11.3 kg)	22.6 mg	39.6 mg (50mg tablet)	56.5 mg (50mg tablet)	As needed or every 8-24 hours

Parenthetical tablet amounts are arithmetic comparisons only. They do not account for scoring, release type, concentration, product labeling, or whether this medication is appropriate for an individual animal.

By Weight

Desyrel reference by cat weight

Choose a common weight to open its optional reference page. Use the main medication calculator for a different exact weight.

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

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How to Give Trazodone to Your Cat

Trazodone tablets can be given whole, hidden in a pill pocket or soft treat, or crushed and mixed into a small amount of wet food. 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, administer 1.5-2 hours before the appointment.

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)

Calculator Limits · 14

When not to use this calculator

This calculator gives a general educational estimate for a healthy adult cat at a known weight. 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?

The typical dose of trazodone for cats is 2-5 mg/kg. Most veterinarians start at the low end (around 2-3 mg/kg) and increase if needed. For a 4 kg cat, this means roughly 8-20 mg. Always follow your veterinarian's specific dosing instructions, as individual cats can vary in sensitivity.

How long does trazodone take to work in cats?

Trazodone typically begins working in cats within 1-2 hours after oral administration. For best results before a vet visit, give it 1.5-2 hours before the appointment. Some cats may respond faster, while others may take the full 2 hours to show noticeable sedation.

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.

Use This Guide Safely · 08

What weight alone cannot tell you

The calculator performs one narrow job: it multiplies your cat's weight by the lower, standard, and upper mg/kg values recorded for Desyrel. It cannot decide whether this drug, indication, formulation, or schedule is appropriate for an individual animal.

Context in this medication record

Commonly listed uses: Anxiety and fear reduction, Pre-veterinary visit sedation, Post-surgical confinement stress, Travel anxiety, Inter-cat aggression
Recorded forms: Tablet, Compounded liquid, Compounded transdermal
Reference timing: As needed or every 8-24 hours; onset 1-2 hours; duration 6-12 hours

Individual checks a calculator cannot perform

Confirm the diagnosis and the reason this medication is being considered.
Match the exact product, concentration, route, and whether a tablet may be split.
Account for age, pregnancy, organ function, genetics, allergies, and prior reactions.
Review every prescription, over-the-counter product, and supplement your pet takes.

Recorded cautions

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

Recorded interactions

MAO inhibitors (risk of serotonin syndrome); SSRIs and other serotonergic drugs; CNS depressants (enhanced sedation); Azole antifungals (increased trazodone levels).

These lists reproduce the structured record used by this page and may not be exhaustive. Show your veterinarian the product label and your cat's complete medication list before acting on a number.

Related · 08

Related medications for cats

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.

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.

Source names are shown at the record level; passage-level page and label citations are still being added. 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. PetDosageChart applies the record's mg/kg values to the entered weight and presents the arithmetic result. 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: Doses scale linearly from a standard basis of 3.5 mg per kg (1.59 mg per lb) of body weight, given As needed or every 8-24 hours. The calculator multiplies that basis by your cat's weight and shows an arithmetic comparison with recorded tablet sizes. That comparison does not determine whether a tablet is scored, splittable, or appropriate for your pet.
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