# What Are the Side Effects of Trazodone for Dogs?


## Key Takeaways

- Trazodone, a serotonin modulator, is prescribed for canine anxiety and stress, with common side effects including sedation and mild gastrointestinal upset, typically transient and manageable.
- Serious adverse events requiring immediate veterinary intervention include seizures, collapse, difficulty breathing, severe vomiting, and signs of serotonin syndrome (agitation, tremors, rigidity, fever), a rare but life-threatening condition due to excessive serotonin levels.
- Less common side effects can manifest as paradoxical agitation, restlessness, or mild hypotension leading to wobbliness, necessitating veterinary consultation for dose adjustment or alternative therapies.
- Always administer trazodone precisely as prescribed by a veterinarian, as incorrect dosing or abrupt cessation can lead to adverse outcomes; never administer human medications for side effects without veterinary guidance.
- Close monitoring for the first 72 hours post-administration is crucial, with owners advised to document specific symptoms, timing, and dosage to facilitate accurate veterinary assessment and management.
- Veterinary consultation is essential for any concerning signs, with a clear distinction between mild, observable side effects and emergent conditions requiring immediate emergency clinic referral.

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Trazodone is a medication commonly prescribed by veterinarians to help dogs cope with anxiety, fear, and stressful situations. It is often used before vet visits, during thunderstorms, or while traveling. Most dogs tolerate it well, but side effects can happen. The most common ones are sedation and mild stomach upset. These are usually temporary and not dangerous.

However, some side effects are serious and need immediate veterinary care. If your dog shows any of these signs, stop giving the medication and go to an emergency vet right away: seizures, collapse, difficulty breathing, severe vomiting, or a very high heart rate. Also watch for signs of serotonin syndrome, which is a rare but life-threatening reaction. These signs include agitation, tremors, rigid muscles, fever, and rapid breathing. Do not wait to see if these improve. Go now.

This article explains what to expect after giving trazodone, what is normal, and what is not. It will help you decide whether to call your vet, book an appointment, or head to an emergency clinic. Always follow the dose your veterinarian prescribed. Never adjust it on your own.

## Is This an Emergency?

The table below sorts common signs into three levels. Use it as a quick guide, but trust your instincts. If you feel something is very wrong, call your vet or an emergency clinic.

| Go to an emergency vet now | Book a same-day appointment | Watch at home for 24 hours |
| --- | --- | --- |
| Seizures or convulsions | Vomiting that happens more than twice in 12 hours | Sleepiness that lasts longer than 12 hours |
| Collapse or inability to stand | Diarrhea that is watery or frequent | Mild wobbliness when walking |
| Difficulty breathing or very fast breathing at rest | Refusing food for more than 24 hours | Slight decrease in appetite |
| Tremors or shaking that will not stop | Extreme agitation, pacing, or restlessness | Soft, formed stools |
| Rigid or stiff muscles, especially with a fever | Excessive drooling or foaming at the mouth | Mild lethargy that improves with rest |
| Very high heart rate, over 160 beats per minute at rest | Signs of anxiety that get worse instead of better | Occasional whining or vocalizing |
| Uncontrolled vomiting, especially with blood | Skin rash, hives, or swelling of the face | Increased thirst for one day |

If you are unsure which category fits, call your veterinarian. Describe what you see in detail. They can help you decide. Do not give another dose of trazodone until you have spoken to them.

## What Is Trazodone and How Does It Work?

Trazodone is a type of medication called a serotonin modulator. Serotonin is a chemical in the brain that helps regulate mood, sleep, and anxiety. Trazodone increases the effect of serotonin, which helps calm a dog without putting them fully to sleep. It is not a sedative in the traditional sense, but it often makes dogs drowsy as a side effect.

Your veterinarian will prescribe a specific dose based on your dog's weight, age, and health history. The dose is not the same for every dog. Giving too much can cause serious problems, and giving too little will not help. Always measure the medication exactly as directed. The FDA provides guidance on giving pet medications safely, including checking the label and asking your vet if you have questions. You can read that guidance at the FDA's page on safe use of pet medications.

## Common Side Effects: What You Are Likely to See

The most common side effect is sedation. Your dog may seem sleepy, relaxed, or less responsive than usual. This often starts within one to two hours after giving the medication and can last for several hours. Some dogs sleep deeply, while others just seem calm and quiet. This is expected and usually not a problem.

Another common side effect is mild gastrointestinal upset. Your dog may vomit once, have soft stools, or eat less than normal. These signs usually pass within a day. If your dog vomits once but otherwise seems fine, you can watch them closely. If vomiting continues or your dog seems painful, call your vet.

Some dogs show the opposite of sedation. They may become restless, pace, or seem agitated. This is less common but can happen. If this occurs, contact your veterinarian. They may adjust the dose or suggest a different medication. The American Veterinary Medical Association offers general guidance on working with your vet to manage your pet's health, which you can find at their pet owner resources page.

## Less Common Side Effects to Know About

Some dogs develop low blood pressure, which can make them feel weak or dizzy. You might notice your dog stumbling or seeming unsteady on their feet. This is usually mild and temporary. If your dog cannot stand or walk, that is an emergency.

Increased thirst and urination can occur. Your dog may drink more water and need more bathroom breaks. This is not dangerous on its own, but make sure fresh water is always available.

A small number of dogs become more anxious or fearful instead of calmer. This is called a paradoxical reaction. If your dog seems more stressed after the medication, do not give another dose. Call your vet for advice.

## Serotonin Syndrome: A Rare but Serious Risk

Serotonin syndrome happens when serotonin levels become too high in the brain. It is rare with trazodone alone, but it can occur if your dog takes other medications that also affect serotonin. These include certain antidepressants, some pain medications, and some supplements. Always tell your veterinarian about every medication and supplement your dog receives.

Signs of serotonin syndrome include agitation, confusion, tremors, muscle rigidity, fever, rapid heart rate, and rapid breathing. This condition can be fatal if not treated quickly. If you see any combination of these signs, go to an emergency vet immediately. Do not wait to call your regular vet during business hours.

The MSD Veterinary Manual, written for pet owners, explains that serotonin syndrome requires urgent veterinary treatment. You can find more information at the MSD Veterinary Manual pet owner version.

## What Else Could Be Going On?

Not every sign after giving trazodone is caused by the medication. Your dog could have an unrelated illness, such as a stomach bug or an infection. They could also be reacting to something else in their environment, like a new food or a plant they chewed.

If your dog has an underlying health condition, such as liver or kidney disease, trazodone may affect them differently. Your veterinarian should know your dog's full medical history before prescribing this drug. If you have not mentioned a health condition, call them to discuss it.

The American Animal Hospital Association provides resources on preventive care and working with accredited veterinary practices. You can find those at their pet owner resources page. These resources can help you understand what to expect during a vet visit and how to ask good questions.

## When to Call Your Veterinarian

Call your veterinarian if you have any concerns, even if you are not sure they matter. It is better to ask than to worry. Describe what you see, when it started, and how long it has lasted. Your vet can tell you whether to continue the medication, stop it, or come in for an exam.

If your dog has a serious reaction, do not call first. Go to the nearest emergency veterinary clinic. Time matters in these situations. Keep the medication bottle with you so the emergency team knows exactly what your dog received.

## What You Can Do at Home Right Now

If your dog is already on trazodone and you are seeing side effects, start with the basics. Keep your dog quiet, comfortable, and hydrated. Offer small amounts of water frequently. Do not force your dog to eat, but do offer a bland meal like boiled chicken and rice if they seem interested.

For mild sedation or wobbliness, keep your dog away from stairs, furniture edges, and other dogs. A quiet room with soft bedding is best. Do not let them off leash outside. Their coordination may be off, and they could stumble into traffic or fall.

For mild stomach upset, such as one episode of vomiting or soft stool, you can hold food for a few hours and then offer small meals. Do not give any over-the-counter human medications for vomiting or diarrhea. Many human drugs are toxic to dogs.

Do not give another dose of trazodone if your dog is showing serious side effects. Do not stop the medication abruptly without talking to your veterinarian, but do call before the next scheduled dose if you are worried.

Never give your dog extra trazodone to "calm them down faster." Never combine trazodone with other sedatives, anti-anxiety drugs, or sleep aids unless your veterinarian has specifically directed it. The risk of dangerous interactions is real.

## What to Write Down Before You Call

Before you contact your veterinarian, gather specific information. This saves time and helps them give you better advice.

Write down:

- The exact time you gave the last dose
- The strength of the tablet and how much you gave
- What your dog ate and drank in the last 12 hours
- How many times your dog vomited or had diarrhea, and when
- Whether your dog is drinking more or less than usual
- Whether your dog seems restless, agitated, or unusually sleepy
- Any tremors, twitching, or stiffness you have seen
- Your dog's breathing rate at rest. Count breaths for 15 seconds and multiply by 4. Normal is usually 15 to 30 breaths per minute.

Take a short video of any unusual behavior. A video of a tremor or a wobbling walk is far more useful than a description.

## Side-Effect Frequency and What to Watch For

The table below gives a general sense of how often side effects appear. Every dog is different. Your veterinarian prescribed this drug for a reason, and most dogs tolerate it well.

| Side Effect | How Common | What You Might See | What to Do |
|---|---|---|---|
| Sedation, sleepiness | Very common | Sleeping more, slow to wake, less playful | Usually mild and fades in a few days. Keep the dog safe and quiet. |
| Wobbliness, incoordination | Common | Stumbling, swaying, bumping into things | Keep the dog confined to safe areas. Call if it worsens or lasts more than a day. |
| Vomiting | Common | One or two episodes shortly after a dose | Hold food, offer water. Call if vomiting repeats or continues past 12 hours. |
| Diarrhea | Common | Soft or loose stool, more frequent bowel movements | Offer bland food. Call if there is blood or if it lasts more than 24 hours. |
| Increased thirst or urination | Less common | Drinking more, asking to go out more often | Make sure water is always available. Mention it at your next check. |
| Restlessness, agitation | Less common | Pacing, panting, unable to settle | Call your veterinarian. This can be a sign the dose is too high. |
| Tremors, twitching | Rare | Shaking, muscle twitches, stiffness | Call immediately. This can be a sign of serotonin syndrome. |
| Collapse, difficulty breathing | Very rare | Unable to stand, pale gums, labored breathing | This is an emergency. Go to an emergency clinic now. |

## What a Veterinary Visit Usually Involves

If you call about side effects, your veterinarian will likely ask about the timing of the dose, your dog's weight, and any other medications or supplements your dog takes. They will ask about medical conditions like liver or kidney disease, because those can affect how the drug is processed.

A routine visit for this problem usually includes a physical exam. The veterinarian will check your dog's temperature, heart rate, breathing, and gum color. They may feel the abdomen to check for pain or bloating. They may watch your dog walk to assess coordination.

Bloodwork is not always needed. It is more likely if your dog is vomiting repeatedly, seems very lethargic, or has an underlying health condition. A basic blood panel checks liver and kidney function, which matter for drug clearance. In rare cases, a veterinarian may recommend a test to measure drug levels, but this is uncommon.

The cost of a visit varies widely by region and clinic. An office visit typically ranges from 50 to 150 dollars. Bloodwork adds roughly 100 to 250 dollars. Emergency or after-hours visits cost more, often 150 to 300 dollars just for the exam. These are general ranges, not quotes. Call ahead for exact pricing.

Most side effects resolve with a dose adjustment or a change in how the drug is given. Your veterinarian may recommend giving the medication with food, splitting the dose, or switching to a different medication entirely. Do not adjust the dose yourself.

## When an Online Vet Can Help, and When It Cannot

Some situations in this article require hands-on care and must not be handled remotely. If your dog collapses, has difficulty breathing, has seizures, cannot stand, or has pale or blue gums, that is an emergency. No video call can replace an emergency room. Go now.

If your dog is vomiting repeatedly, has bloody diarrhea, or shows tremors that could be serotonin syndrome, you need an in-person examination. These signs can progress quickly, and a remote vet cannot measure blood pressure, check heart rhythm, or run bloodwork.

A remote consultation is genuinely useful for early or mild presentations. If your dog is a little sleepier than usual after a dose, or had one soft stool, a video call can help you decide whether a visit is needed. A remote vet can take a detailed history, watch your dog move on video, and advise on whether a sign warrants a trip to the clinic.

A remote vet can also help with rechecks on a known problem. If your dog has been on trazodone for two weeks and you want to discuss tapering, or if you have a question about a side effect that is mild and stable, telemedicine can work well.

What a remote vet cannot do is palpate the abdomen, listen to the chest, take a temperature, run bloodwork, or image anything. They cannot feel a painful belly or hear a heart murmur. They also cannot see subtle changes in gum color that a physical exam would reveal.

Prescribing rules differ by state. Some states allow a veterinarian to prescribe after a video consult. Others require an in-person examination first. Your remote vet will tell you what their rules allow. If they cannot prescribe, they will refer you to a local clinic.

The US Food and Drug Administration advises that giving medication safely starts with clear instructions from your veterinarian. Whether that conversation happens in person or by video, make sure you understand the dose, the timing, and what to do if you miss a dose. The [FDA guidance on giving your pet medicine safely](https://www.fda.gov/animal-veterinary/animal-health-literacy/how-give-your-pet-medicine-safely) is a useful reference. The [American Veterinary Medical Association](https://www.avma.org/resources-tools/pet-owners) also offers practical advice on working with your veterinarian and knowing when to seek care.

## Common Mistakes Owners Make With Trazodone

Many owners worry about side effects that never happen, while missing the mistakes that cause real problems. The most common error is changing the dose on their own. A dog that seems too sleepy today might need a lower dose tomorrow, but that decision belongs to your veterinarian. The FDA warns that giving the wrong amount of pet medication is one of the most frequent causes of treatment problems. Always confirm the dose with your vet before changing anything.

Another frequent mistake is stopping the drug abruptly. Trazodone is not addictive, but stopping suddenly can cause rebound anxiety that looks worse than the original problem. If your dog has been taking it daily for more than a few weeks, ask your vet how to taper the dose down gradually.

Owners also confuse sedation with a bad reaction. A sleepy dog is the expected effect, not a side effect to fear. The problem is when sedation is so deep that the dog cannot be roused, will not eat or drink, or seems unsteady on their feet. That level of sedation needs a phone call to your vet.

| Common Mistake | What to Do Instead |
| --- | --- |
| Giving a "little extra" because the dog seems anxious | Call your vet first. Extra trazodone can cause dangerous oversedation. |
| Stopping the drug cold turkey | Ask your vet about a gradual reduction plan. |
| Skipping doses because the dog seems fine | Follow the prescribed schedule. Trazodone works best when given consistently. |
| Hiding the pill in food that the dog spits out | Confirm the pill was swallowed. A half dose can cause uneven effects. |
| Assuming all sedation is a bad reaction | Mild sleepiness is expected. Deep, unrousable sleep is not. |

## How to Reduce the Chance of Side Effects

Start with the lowest effective dose your veterinarian recommends. This is not a drug where "more is better." The right dose for a 20 kg dog is very different from the right dose for a 40 kg dog, and your vet calculates this based on your dog's weight, health history, and the reason for treatment.

Give the medication at the same time each day. For situational anxiety, such as fireworks or vet visits, give it one to two hours before the stressful event as directed. For daily anxiety, a consistent schedule helps the drug reach a steady level in the body.

Watch your dog closely for the first three days. This is when most side effects appear. Keep a simple log of how sleepy they are, how much they eat, and whether they vomit or have diarrhea. This information is gold for your vet if adjustments are needed.

Do not combine trazodone with other sedatives, including over-the-counter products like melatonin or Benadryl, without explicit approval from your vet. Drug interactions are a leading cause of adverse reactions. The American Veterinary Medical Association advises pet owners to keep a complete list of every medication and supplement their dog takes.

## What Recovery and Ongoing Management Usually Look Like

Most side effects resolve within 24 to 48 hours of stopping the drug or adjusting the dose. Mild sedation often fades as the dog's body adjusts over the first week. Gastrointestinal upset usually settles within a few days, especially if you give the medication with a small meal.

For dogs on daily trazodone for anxiety, the full benefit may take one to two weeks to appear. This is not a drug that works instantly. Your vet will likely schedule a recheck after two to four weeks to assess progress and adjust the dose.

If trazodone is used for situational anxiety, such as thunderstorms or travel, you may only need it on an as-needed basis. Many dogs do well with this approach for months or years. Others eventually need a different medication or a combination approach. The American Animal Hospital Association recommends regular rechecks to ensure the treatment plan still fits your dog's needs.

If your dog had a serious reaction like serotonin syndrome, recovery depends on how quickly treatment began. Hospitalization may be needed for one to several days. After discharge, your vet will guide you on whether any other anxiety medication is safe to try.

## Frequently Asked Questions

**Can I give my dog trazodone with food?**
Yes, giving trazodone with a small meal often reduces nausea and stomach upset. A bland meal like plain boiled chicken and rice can help if your dog has a sensitive stomach. Do not give the medication with a large fatty meal unless your vet approves, because that can change how the drug is absorbed. If your dog vomits within 30 minutes of taking the pill, call your vet before giving another dose.

**How long does trazodone stay in a dog's system?**
The drug typically lasts about 8 to 12 hours in most dogs, but this varies widely by individual. Some dogs metabolize it faster, others slower. Older dogs and dogs with liver or kidney disease may clear it more slowly. This is why your vet chooses a specific dosing interval. Do not assume a shorter duration means you can give another dose early.

**My dog is panting and restless after trazodone. Is this normal?**
Paradoxical agitation happens in a small number of dogs. Instead of calming down, they become more anxious, restless, or pant excessively. This usually appears within the first hour or two after dosing. Contact your vet if this occurs. They may lower the dose, switch to a different medication, or recommend a different approach entirely.

**Can trazodone be used long term?**
Yes, many dogs take it for months or years under veterinary supervision. Long-term use is generally considered safe, but your vet should recheck your dog periodically to confirm the dose still works and to monitor for any health changes. Do not assume that because a dose worked for a year, it will work forever. Anxiety can change over time.

**What if I miss a dose?**
Give the missed dose as soon as you remember, unless it is almost time for the next dose. In that case, skip the missed dose and resume the normal schedule. Never give two doses at once. If you are unsure what to do, call your vet. Missing one dose is not dangerous, but doubling up can cause oversedation.

**Is trazodone safe for puppies?**
Trazodone can be used in puppies, but only under veterinary guidance. Puppies are still developing, and their metabolism of drugs changes as they grow. Your vet will adjust the dose based on your puppy's current weight and may want to recheck more frequently. Never give a puppy a dose meant for an adult dog. The FDA provides guidance on safe medication use for pets of all ages.

## Related Clinical & Scientific Guides

* [What Are the Side Effects of Bravecto for Dogs? What to Watch For](/knowledge/veterinary-medicine/pet-medication-guide/bravecto-side-effects-dogs)
* [Can You Give Your Dog Human Allergy Medicine? Whats Safe](/knowledge/veterinary-medicine/pet-medication-guide/dog-human-allergy-medicine-safe)
* [Can You Give Your Dog Dramamine for Car Sickness?](/knowledge/veterinary-medicine/pet-medication-guide/dog-dramamine-car-sickness)


## References and Further Reading

- [FDA Center for Veterinary Medicine Animal Drug Information](https://www.fda.gov/animal-veterinary)
- [FDA Safe Use of Pet Medications](https://www.fda.gov/animal-veterinary/animal-health-literacy/how-give-your-pet-medicine-safely)
- [AVMA Pet Owner Resources](https://www.avma.org/resources-tools/pet-owners)
- [MSD Veterinary Manual Pet Owner Version](https://www.msdvetmanual.com/pet-owners)
- [AAHA Pet Owner Resources](https://www.aaha.org/for-pet-parents/)

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> This article is general educational information for pet owners. It is not a substitute for veterinary diagnosis, examination, or treatment. If your pet is showing severe or rapidly worsening signs, contact an emergency veterinary hospital immediately.