Skip to main content
PetDosageChart

Serotonin antagonist and reuptake inhibitor (SARI) · For Dogs

Trazodone dosage reference for dogs (Desyrel)

This page's standard weight-based reference is 5 mg per kg (2.27 mg per lb), with every 8-24 hours recorded as the reference frequency. Use the calculator to see the arithmetic for your dog's weight, then confirm the indication, product, and actual dose with a veterinarian.

Onset
1-2 hours
Duration
4-8 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, noise phobia, post-surgery sedation, separation anxiety, and veterinary visit anxiety. Understanding the correct dosage, administration, and potential side effects of Trazodone is critical for your dog’s safety and well-being.

A typical Trazodone dose for dogs is around 5 mg/kg every 8-24 hours, within a usual range of 2-10 mg/kg. Available forms include tablet.

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 Dogs

Enter your dog’s weight below to estimate the Trazodone dose from the 5 mg/kg guideline. Your veterinarian may adjust it for your dog’s age, condition, and other medications, so treat the result as an educational starting point, not a prescription.

Dosage Calculator · 01

Enter your dog's weight

Quick Dosage Chart

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

Dosage Chart · 02

Desyrel weight-based reference chart for dogs

Scroll sideways to see full table

Weight Lower Reference Standard Reference Upper Reference Frequency
5 lbs (2.3 kg) 4.6 mg 11.5 mg 23.0 mg every 8-24 hours
10 lbs (4.5 kg) 9.0 mg 22.5 mg 45.0 mg (50mg tablet) every 8-24 hours
15 lbs (6.8 kg) 13.6 mg 34.0 mg 68.0 mg every 8-24 hours
20 lbs (9.1 kg) 18.2 mg 45.5 mg (50mg tablet) 91.0 mg (2 × 50mg) every 8-24 hours
25 lbs (11.3 kg) 22.6 mg 56.5 mg (50mg tablet) 113.0 mg every 8-24 hours
30 lbs (13.6 kg) 27.2 mg 68.0 mg 136.0 mg every 8-24 hours
40 lbs (18.1 kg) 36.2 mg 90.5 mg (2 × 50mg) 181.0 mg every 8-24 hours
50 lbs (22.7 kg) 45.4 mg (50mg tablet) 113.5 mg 227.0 mg every 8-24 hours
60 lbs (27.2 kg) 54.4 mg (50mg tablet) 136.0 mg 272.0 mg every 8-24 hours
70 lbs (31.7 kg) 63.4 mg 158.5 mg (3 × 50mg) 317.0 mg every 8-24 hours
80 lbs (36.3 kg) 72.6 mg 181.5 mg 363.0 mg every 8-24 hours
90 lbs (40.8 kg) 81.6 mg 204.0 mg (4 × 50mg) 408.0 mg (8 × 50mg) every 8-24 hours
100 lbs (45.4 kg) 90.8 mg (2 × 50mg) 227.0 mg 454.0 mg (9 × 50mg) every 8-24 hours
120 lbs (54.4 kg) 108.8 mg (2 × 50mg) 272.0 mg 544.0 mg (11 × 50mg) every 8-24 hours
150 lbs (68 kg) 136.0 mg 340.0 mg (7 × 50mg) 680.0 mg 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 dog 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.

Embed this calculator on your site

Get a free Trazodone dosage widget

Get embed code

Free forever. Works in any blog post or article. Adds a small "Powered by petdosagechart.com" credit at the bottom.

Event Dosing and Ongoing Treatment Are Different Questions

The 5 mg/kg value on this page is a standard arithmetic reference inside a wide recorded range. It does not decide whether trazodone is being used once before a predictable event, during recovery, or as part of an ongoing behavior plan. Timing, repeat dosing, and tapering can differ across those situations.

Trazodone also cannot be evaluated in isolation. Other medicines that affect serotonin or cause sedation can change both the expected effect and the risk. Give the veterinarian a complete list that includes supplements and as-needed medicines; do not use visible anxiety or lack of sleepiness as a reason to repeat a dose early.

Before the first dose, ask what effect should be visible, how long to wait, what to do if the dog becomes more agitated, and which symptoms could indicate serotonin syndrome or another serious reaction.

How to Give Trazodone to Your Dog

Trazodone can be given with or without food, but giving with food may reduce nausea. For event-based anxiety (thunderstorms, vet visits), give 1-2 hours before the anticipated event. Do not abruptly stop if your dog has been on trazodone for more than a few weeks — taper gradually under veterinary guidance.

It is generally recommended to give Trazodone with food to help reduce stomach upset. It may interact with MAO inhibitors, SSRIs, buspirone, tramadol, and other serotonergic drugs.

Side Effects and Safety

Common side effects include sedation, lethargy, gastrointestinal upset, panting, and restlessness. More serious side effects can occur, such as serotonin syndrome, priapism, severe aggression, and cardiac arrhythmias.

Cautions · 12

When Desyrel should be used with caution or avoided

Some dogs 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.

  • use with MAO inhibitors
  • severe liver disease
  • known hypersensitivity

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 dog's medications and supplements.

MAO inhibitors
SSRIs
buspirone
tramadol
other serotonergic drugs

Calculator Limits · 14

When not to use this calculator

This calculator gives a general educational estimate for a healthy adult dog 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 dogs
  • 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 dog's current, accurate weight
  • For combination products that contain additional active ingredients

Overdose · 15

Suspected overdose: what to do

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

Frequently Asked Questions

Frequently Asked · 07

Questions about this medication

How long does trazodone take to work in dogs?
Trazodone typically begins working within 1-2 hours of oral administration. For best results with event-based anxiety (such as thunderstorms or vet visits), give the medication at least 1-2 hours before the anticipated stressful event.
Can I give my dog trazodone every day?
Yes, trazodone can be prescribed for daily use in dogs with chronic anxiety. However, daily use should always be under veterinary supervision. If your dog has been taking trazodone daily for several weeks, do not stop abruptly — work with your vet to taper the dose gradually to avoid withdrawal effects.
What does trazodone do to a dog?
Trazodone works by increasing serotonin activity in the brain, which produces a calming, anti-anxiety effect. It helps reduce fear, anxiety, and stress-related behaviors. Most dogs become noticeably calmer and may appear mildly sedated, especially at higher doses.
How long does trazodone last in dogs?
The effects of trazodone typically last 4-8 hours in dogs, though this can vary based on the individual dog, dose, and whether it was given with food. Some dogs may experience sedation for up to 12 hours, especially with higher doses.
Can you give a dog trazodone and Benadryl together?
Trazodone and Benadryl can sometimes be used together in dogs, but only under veterinary guidance. Both medications cause sedation, so combining them can lead to excessive drowsiness. Your vet may recommend this combination for severe anxiety situations but will adjust doses accordingly.
How much trazodone can I give my dog?
The standard trazodone dose for dogs is about 5 mg per kilogram of body weight (roughly 2-3 mg per pound), with a typical prescribed range of 2-10 mg/kg per dose and a maximum of 15 mg/kg in 24 hours. Doses are usually given every 8-24 hours. Trazodone is a prescription medication and dosing varies widely between dogs, so always confirm the exact dose with your vet.
How much trazodone to give a 10 lb dog?
A 10 lb dog (about 4.5 kg) would receive roughly 22 mg of trazodone at the standard 5 mg/kg dose, which in practice is often rounded to about half of a 50 mg tablet. Because the prescribed range (2-10 mg/kg) is wide and trazodone only comes in 50 mg and larger tablets, your vet will set the exact tablet fraction. Give every 8-24 hours as directed.
How much trazodone to give a 25 lb dog?
A 25 lb dog (about 11.3 kg) would receive roughly 57 mg of trazodone at the standard 5 mg/kg dose, which is close to one 50 mg tablet. Depending on your dog and the situation, your vet may prescribe anywhere from about 23 mg to 113 mg (the 2-10 mg/kg range). Confirm the exact dose with your vet.
How much trazodone to give a 50 lb dog?
A 50 lb dog (about 22.7 kg) would receive roughly 113 mg of trazodone at the standard 5 mg/kg dose, which is close to one 100 mg tablet. Within the prescribed 2-10 mg/kg range a vet might use anywhere from about 45 mg to 225 mg per dose. Give every 8-24 hours as directed by your vet.
How much trazodone to give a 75 lb dog?
A 75 lb dog (about 34 kg) would receive roughly 170 mg of trazodone at the standard 5 mg/kg dose, which is close to one 150 mg tablet. Larger dogs often fall in the 100-300 mg per-dose range depending on the situation. Because trazodone dosing is individualized, confirm the exact amount and tablet size with your vet.
How much trazodone to give a 100 lb dog?
A 100 lb dog (about 45 kg) would receive roughly 225 mg of trazodone at the standard 5 mg/kg dose, often given as a 150 mg tablet plus a 50 mg tablet (or similar combination). At this size some dogs are prescribed up to about 300-450 mg for short-term events under the 2-10 mg/kg range. Always confirm the exact dose with your vet.
How long does it take for trazodone to wear off in a dog?
The calming effects of trazodone typically last 4-8 hours in dogs, so most dogs return to their baseline within that window after a single dose. Some dogs, especially those on higher doses, may seem mildly sedated for up to 12 hours. If your dog still seems heavily sedated well beyond a day, contact your vet.
What factors affect how long trazodone lasts in a dog?
How long trazodone lasts varies with the individual dog, the dose given, whether it was taken with food, and your dog's metabolism, age, and liver function. Higher doses and impaired liver function can prolong the effect, while a larger or faster-metabolizing dog may clear it sooner. Other serotonergic medications can also change how the drug behaves, so always tell your vet about everything your dog takes.
Should I give trazodone before a stressful event or every day?
Trazodone can be used both ways. For event-based anxiety such as thunderstorms, fireworks, or vet visits, it is typically given 1-2 hours before the anticipated stressor so it takes effect in time. For chronic or daily anxiety it can be given on an ongoing schedule, but only under veterinary supervision. If your dog has been on daily trazodone for more than a few weeks, do not stop abruptly; taper gradually with your vet to avoid withdrawal effects.
What are the side effects of trazodone in dogs?
The most common side effects are sedation, lethargy, and mild gastrointestinal upset; some dogs also pant or seem restless. Giving the dose with food can reduce nausea. Most of these effects are mild and fade as your dog adjusts, but contact your vet if they are severe or persistent.
What are the serious side effects of trazodone in dogs?
Rare but serious reactions include serotonin syndrome (tremors, agitation, high heart rate, fever), priapism (a persistent, painful erection that is a medical emergency), severe aggression, and cardiac arrhythmias. Serotonin syndrome risk rises when trazodone is combined with other serotonergic drugs such as SSRIs, tramadol, or MAO inhibitors. Seek emergency veterinary care right away if you see tremors, seizures, collapse, severe agitation, or an irregular heartbeat.
Trazodone vs gabapentin for dogs: which is better?
Both trazodone and gabapentin are used to calm dogs for stressful events such as vet visits or travel, but they work differently. Trazodone increases serotonin activity in the brain to reduce fear and anxiety, while gabapentin is an anticonvulsant and pain medication that produces sedation and mild anxiety relief. Vets sometimes prescribe them together for severe situational anxiety. Neither is universally "better"; the right choice depends on your dog, the situation, and any other conditions, so your vet will decide which fits best.

Use This Guide Safely · 08

What weight alone cannot tell you

The calculator performs one narrow job: it multiplies your dog'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, noise phobia, post-surgery sedation, separation anxiety, veterinary visit anxiety
Recorded forms
tablet
Reference timing
every 8-24 hours; onset 1-2 hours; duration 4-8 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

use with MAO inhibitors; severe liver disease; known hypersensitivity.

Recorded interactions

MAO inhibitors; SSRIs; buspirone; tramadol; other serotonergic drugs.

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

For Cats

Looking for Trazodone dosage for cats?

View the Trazodone dosage chart and calculator for cats.

Related · 08

Related medications for dogs

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.

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 5 mg per kg (2.27 mg per lb) of body weight, given every 8-24 hours. The calculator multiplies that basis by your dog'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 dogs dosage data.

Safety · 10

More resources