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Serotonin antagonist and reuptake inhibitor (SARI) · For Dogs

How much Trazodone (Desyrel) can I give my dog?

Standard Trazodone dose for dogs is 5 mg per kg (2.27 mg per lb), given every 8-24 hours. Use the calculator below for your dog's exact weight, or jump to the weight-by-weight chart.

Onset
1-2 hours
Duration
4-8 hours
Class
Serotonin antagonist and reuptake inhibitor (SARI)

Calculator estimate from Plumb’s Veterinary Drug Handbook. Not yet vet-reviewed — see our methodology .

This dosage information is for educational purposes only. Always consult your veterinarian before giving any medication to your pet. Dosages may vary based on your pet's health conditions, other medications, and individual factors.

Content reviewed by licensed veterinarians. Sourced from Plumb's Veterinary Drug Handbook and the Merck Veterinary Manual.

Dosage Calculator · 01

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By Weight

Desyrel dose by dog weight

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Dosage Chart · 02

Desyrel dosage for dogs by weight

Scroll sideways to see full table

Weight Low Dose Standard Max Safe Frequency
5 lbs (2.3 kg) 4.5mg 11.5mg 23mg every 8-24 hours
10 lbs (4.5 kg) 9mg 22.5mg 45mg (50mg tablet) every 8-24 hours
15 lbs (6.8 kg) 13.5mg 34mg 68mg every 8-24 hours
20 lbs (9.1 kg) 18mg 45.5mg (50mg tablet) 91mg (2 × 50mg) every 8-24 hours
25 lbs (11.3 kg) 22.5mg 56.5mg (50mg tablet) 113mg every 8-24 hours
30 lbs (13.6 kg) 27mg 68mg 136mg every 8-24 hours
40 lbs (18.1 kg) 36mg 90.5mg (2 × 50mg) 181mg every 8-24 hours
50 lbs (22.7 kg) 45.5mg (50mg tablet) 113.5mg 227mg every 8-24 hours
60 lbs (27.2 kg) 54.5mg (50mg tablet) 136mg 272mg every 8-24 hours
70 lbs (31.7 kg) 63.5mg 158.5mg (3 × 50mg) 317mg every 8-24 hours
80 lbs (36.3 kg) 72.5mg 181.5mg 363mg every 8-24 hours
90 lbs (40.8 kg) 81.5mg 204mg (4 × 50mg) 408mg (8 × 50mg) every 8-24 hours
100 lbs (45.4 kg) 91mg (2 × 50mg) 227mg 454mg (9 × 50mg) every 8-24 hours
120 lbs (54.4 kg) 109mg (2 × 50mg) 272mg 544mg (11 × 50mg) every 8-24 hours
150 lbs (68 kg) 136mg 340mg (7 × 50mg) 680mg every 8-24 hours

Common Uses · 03

What is Desyrel (Trazodone) used for in dogs?

anxiety noise phobia post-surgery sedation separation anxiety veterinary visit anxiety

Administration · 04

How to give Desyrel 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.

Available Forms

tablet

Give with Food?

Yes — give with food

Side Effects · 05

Side effects of Desyrel in dogs

Common side effects

sedation
lethargy
gastrointestinal upset
panting
restlessness

Serious side effects — call your vet

  • serotonin syndrome
  • priapism
  • severe aggression
  • cardiac arrhythmias

Emergency · 06

When to call the vet

Call your vet immediately if your dog shows any of these signs:

  • Tremors or seizures
  • Severe agitation or aggression
  • Vomiting or diarrhea
  • Collapse or extreme weakness
  • Rapid or irregular heartbeat

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 dosage information on this page is compiled from the following veterinary and pharmaceutical references:

  • Plumb's Veterinary Drug Handbook — the standard veterinary pharmacology reference used by veterinarians worldwide.
  • Merck Veterinary Manual — a trusted, peer-reviewed resource for veterinary professionals and pet owners.
  • DailyMed (FDA Drug Labels) — official FDA-approved drug labeling and prescribing information for Trazodone.

Read more about our methodology and how we calculate dosages.

Transparency · 11

How this page was made

Sourced from Plumb's Veterinary Drug Handbook, the reference used in US vet schools. Every dose, frequency, and tablet count on this page is generated from that data, then checked against the published references below.

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 rounds to the closest available tablet size.
Last-reviewed status
Automated from Plumb’s, not yet vet-reviewed.

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

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.

Safety · 10

More resources