20 Min Read
Trazodone Vs. Benadryl For Dogs (Uses, side effects & safety)
Key takeaway
- Trazodone and Benadryl serve different purposes. Despite sometimes being compared for anxiety relief, these medications have different effects when given to dogs.
- Trazodone is a prescription medication specifically used to treat anxiety and behavioral stress in dogs.
- Benadryl is an over-the-counter antihistamine. It can cause drowsiness but is not designed to treat anxiety.
- Benadryl has not been shown to effectively treat anxiety in dogs, even though its sedative effect may appear calming.
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If your dog suffers from anxiety, you might find online articles about different types of medications you can try. Trazodone and Benadryl are two medications used to treat anxiety in dogs. However, they're not the same. Trazodone is a prescription medication that produces a sedative effect, while Benadryl is an antihistamine that can make dogs drowsy.
Figuring out which medication is right for your anxious dog is crucial. Some pet parents may use Benadryl to help their dogs sleep during stressful situations like thunderstorms, fireworks, and vet visits. However, there are currently no clinical studies demonstrating its efficacy in treating anxiety in dogs. On the other hand, trazodone is a proven effective treatment for mild to severe anxiety in dogs, and it's a fast-acting short-lived medication that can help with various types of dog anxiety.
When comparing trazodone vs. Benadryl for dog anxiety, you should talk to your vet or a veterinary behaviorist who can help you learn more about your dog's anxiety or behavioral issues and find the best solution. This article will discuss everything you need to know about trazodone vs. Benadryl for dogs to help calm your anxious pup.
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- What Is Trazodone?
- What Is Benadryl?
- Comparing Trazodone Vs. Benadryl
- Treating Anxiety In Dogs
- FAQs
- Final Notes
What is Trazodone?
Trazodone is an anti-anxiety medication for dogs and cats. As a serotonin antagonist reuptake inhibitor (SARI) medication, it's used to treat a variety of behavioral issues in dogs, including separation anxiety, noise phobias, and situational anxiety. Trazodone is a human medication prescribed off-label for dogs and can help keep them calm in stressful situations.
Typically, trazodone is used as a short-term medication for predictable situational anxiety. For example, if your dog suffers from separation anxiety or fears the vet, you'll give them the proper trazodone dosage a few hours before the stressful event.
Unlike Benadryl, there has been comprehensive research on the effectiveness of trazodone in keeping dogs calm and treating dog anxiety. A recent study by Margaret Gruen and cited by the American Veterinary Medical Association found that in dogs with anxiety given trazodone daily, 72.5% of pet parents stated that the medication was very effective.
Trazodone uses: When do dogs need sedatives?
The most common use of trazodone for dogs is for short-term stress relief. However, since trazodone can take up to two hours or more to start working, you must be able to predict the stressful event. Unfortunately, if there's a storm you didn't know about, and your dog is afraid of thunder, giving them trazodone at the beginning of the storm won't quell their anxiety because the medication takes a few hours to kick in.
A few examples of when trazodone might be right for your dog include the following:
- Separation anxiety: If your dog engages in destructive behavior, excessive vocalization like howling, or any other signs of anxiety while you're away, they may suffer from separation anxiety. Trazodone can reduce your dog's anxiety to help them feel calmer while you're away, also reducing their symptoms to prevent undesirable behaviors.
- Fear of the vet: If your dog is afraid of the vet, trazodone can help your dog stay calm while being examined to ensure they get the treatment they need when needed.
- Noise phobias: Thunderstorms and fireworks are two of the most common noise phobias in dogs. Luckily, they're both predictable. For example, you know your city will probably do fireworks on the Fourth of July, so you can ensure your dog takes trazodone a few hours before they begin to help them stay calm.
- Travel anxiety: If your dog gets anxious while riding in the car, trazodone can help them stay calm and prevent them from trying to escape, vocalizing, or jumping onto you. Of course, we also recommend having a dog seat belt to keep them safe and prevent them from being able to move around the car while you're driving.
- Holidays: The holidays can be stressful for dogs, especially if you're traveling or having company. Even holidays as seemingly innocent as Halloween can cause anxiety in dogs because of unknown sights, sounds, and smells. Trazodone may reduce symptoms of dog anxiety during these times.
How long does trazodone take to work, and how long does it last?
In a recent study on the use of trazodone in dogs after surgery, pet parents reported a median onset of 41 to 45 minutes. However, every dog is different, and it can take your dog much longer to start feeling the effects.
Since trazodone has a half-life of 2 to 3 hours, the effects only last around 6 to 12 hours. But remember, every dog is different. Therefore, it's crucial to monitor your dog when they first take trazodone to help you determine the onset and duration for your particular pet. For example, one dog might experience onset within an hour and have a duration of 10 hours, while another dog might experience onset within two hours with a duration of only six hours.
Additionally, some dogs might require daily trazodone, depending on their type and level of anxiety. If your vet determines your dog should be on trazodone daily, it can take several weeks to observe the full effects, similar to other anti-anxiety medications.
The main purpose of trazodone is to treat dog anxiety with a sedative effect, reducing systems such as:
- Pacing
- Vocalization
- Destructive behavior
- Yawning
- Panting
-
Trying to escape & hiding
Remember, trazodone can take a few hours to kick in, and the effects are short-lived, so it primarily benefits dogs who suffer from predictable situational anxiety or those with triggers.

Trazodone side effects
Trazodone is a prescription anxiety medication for dogs. Unfortunately, while it's clinically proven to reduce anxiety symptoms in pets, every medication has potential side effects.
The most common side effect of trazodone for dogs is sedation, which is often the desired effect. The sedation can help your dog remain calm in stressful situations. A study on the use of trazodone for treating anxiety disorders in dogs found that most dogs tolerated it well, with 80% of dogs having zero adverse side effects.

Other possible side effects include GI upset, such as diarrhea, vomiting, and loss of appetite. However, these symptoms should subside after the trazodone has left their system. If your dog experiences side effects, consult your vet immediately for guidance.
Trazodone dosages
|
Dog Weight |
Low Dose (mg) |
Typical Dose (mg) |
High Dose (mg) |
Frequency |
|
5 lb (2.3 kg) |
5 mg |
10–12 mg |
15 mg |
Every 8–24 h |
|
10 lb (4.5 kg) |
10 mg |
20–25 mg |
30 mg |
Every 8–24 h |
|
20 lb (9.1 kg) |
20 mg |
40–50 mg |
60 mg |
Every 8–24 h |
|
30 lb (13.6 kg) |
30 mg |
60–75 mg |
90 mg |
Every 8–24 h |
|
40 lb (18.2 kg) |
40 mg |
80–100 mg |
120 mg |
Every 8–24 h |
|
60 lb (27.3 kg) |
60 mg |
120–150 mg |
180 mg |
Every 8–24 h |
|
80 lb (36.4 kg) |
80 mg |
160–200 mg |
240 mg |
Every 8–24 h |
|
100 lb (45.5 kg) |
100 mg |
200–250 mg |
300 mg |
Every 8–24 h |
|
120 lb (54.5 kg) |
120 mg |
240–300 mg |
360 mg |
Every 8–24 h |
Trazodone comes in 50, 100, 150, and 300-milligram tablets.5 The recommended dosage is determined by your dog's weight and level of anxiety.
For example, depending on your dog's symptoms, they might recommend a higher dose for vet visits and a lower dose for separation anxiety. In most cases, your vet will start your dog on a low dose and ask that you report back on their anxiety and any side effects to ensure the treatment is safe and effective. From there, your vet might keep the same dosage or continue increasing it to find the best one for your dog.
What is Benadryl?
Benadryl, also known by its generic name diphenhydramine, is an antihistamine sold over the counter. It's most commonly used in people and pets to treat allergic reactions associated with seasonal allergies, bug bites, bee stings, and skin allergies. If you've ever taken Benadryl, you know it can make you drowsy, which is why it's a common anxiety treatment in dogs.
While this medication can make your dog tired, it's not considered an effective anxiety treatment, especially for dogs that suffer from mild to severe anxiety. Unfortunately, the sedative effects of Benadryl are too mild to help with most types of anxiety.
Benadryl uses
As an antihistamine, Benadryl works the same in dogs as in humans, treating a wide range of allergic reactions from seasonal, environmental, and skin allergies. The most common uses of Benadryl for dogs include:
- Swelling and inflammation
- Hives and rashes
- Runny nose and watery eyes
- Coughing
- Sneezing
- Anaphylactic reactions7

Benadryl side effects
The side effects of Benadryl for dogs are similar to those for humans. The most significant side effect is drowsiness. After the Benadryl starts working, you may see a reduction in your dog's allergy symptoms, but they'll probably nap more than usual. That said, your dog will still be able to go for walks and enjoy their favorite activities. If your dog is highly sedated, consult your vet immediately because it might indicate an overdose.
Other common side effects of Benadryl in dogs include:
- Dry mouth
- Urinary retention
- Increased heart rate
- Rapid breathing
- Hypersalivation7
Some dogs shouldn't take Benadryl. While this medication is something you can buy over the counter at any drugstore, you should always consult your vet before administering it to your dog.
Benadryl doses
The recommended Benadryl dosage for dogs depends on their health and weight, and should only be used under the guidance of your vet. While this medication is considered safe for dogs if you follow the recommended dosage, you should stop giving it to them and contact your vet as soon as possible if you notice any side effects. In addition, you should avoid giving Benadryl to puppies that can be more sensitive to some medications.
|
Dog Weight |
Weight (kg) |
Dose Range per Dose (2–4 mg/kg) |
Dosing Frequency |
|
5 lbs |
2.3 kg |
5–9 mg |
2–3 times daily |
|
10 lbs |
4.5 kg |
9–18 mg |
2–3 times daily |
|
20 lbs |
9.1 kg |
18–36 mg |
2–3 times daily |
|
30 lbs |
13.6 kg |
27–54 mg |
2–3 times daily |
|
40 lbs |
18.1 kg |
36–72 mg |
2–3 times daily |
|
50 lbs |
22.7 kg |
45–91 mg |
2–3 times daily |
|
75 lbs |
34 kg |
68–136 mg |
2–3 times daily |
|
100 lbs |
45.4 kg |
91–181 mg |
2–3 times daily |
Benadryl usually takes around a half hour to begin working. If you're using it for allergies, you may notice your dog scratching less or sleeping more because they're drowsy. The effects can last anywhere between eight and 12 hours. However, every dog is different. When you first start administering it to your dog, you can monitor them to determine onset and duration. You should report your findings back to your vet to help them create an effective treatment plan for your dog to prevent allergy symptoms from causing discomfort.
Always consult your vet if you're trying to use Benadryl to alleviate anxiety. It's unlikely they'll use Benadryl to treat your dog's anxiety because there are much more effective medications for mild to severe dog anxiety. However, if your vet chooses to use Benadryl, you should report any changes in behavior or side effects to ensure the medication is safe and effective.
It's crucial to pay close attention to the dosage to prevent potential Benadryl overdose. While rare, an overdose can cause dilated pupils, agitation, rapid heartbeat, constipation, and seizures. If you believe your dog has ingested too much Benadryl, contact your vet as soon as possible or call the Pet Poison Helpline at 855-764-7661 for guidance.
Never give your dog Benadryl without first consulting your vet. As we've mentioned, some dogs shouldn't have Benadryl because of pre-existing health conditions and medications.
Can I give my dog Benadryl for anxiety?
Benadryl causes drowsiness, which may help with circumstantial anxiety in dogs caused by stressful events. It may reduce the symptoms of anxiety in dogs with mild anxiety. However, it's not ideal for dogs struggling with phobias, separation anxiety, fear-based anxiety, or any other type of mild to severe anxiety.6 That said, if your dog experiences anxiety in the car or during thunderstorms, it may help them stay calm because they'll feel tired. However, it's not an effective treatment for most types of anxiety in dogs.
Instead, prescription medications like trazodone are typically much more effective and can help sedate the dog while actively addressing anxiety symptoms.
In a recent study evaluating diphenhydramine as a sedative for dogs, researchers gave dogs diphenhydramine, saline, and acepromazine, a known prescription sedative for dogs. They assessed the dogs' levels of sedation with observation and interaction. Dogs in the acepromazine group experienced much higher levels of sedation than dogs in the saline or diphenhydramine groups.
Additionally, dogs given Benadryl didn't experience significantly different sedation from the dogs in the saline group. The results were that diphenhydramine didn't cause significant sedation in dogs, so it's not a suitable sedative for anxiety management.8
So can Benadryl relieve dog anxiety? Many people theorize that making dogs drowsy can help them stay calm. However, it's not an effective treatment for anxiety disorders in dogs because it doesn't have a significant anti-anxiety effect like other medications. It's possible Benadryl can help your dog stay calm in some situations, but you should always discuss all your options with your vet to ensure that it's the best course of treatment for their anxiety.
Comparing trazodone vs. Benadryl

When comparing Benadryl vs. trazodone, you have to remember they're two completely different medications with different uses. However, one thing they have in common is that they've been used to treat anxiety. Consider the following points when comparing the two medications and deciding which to use for dog:
- Class type: Trazodone is an antidepressant with anti-anxiety properties, while Benadryl is an antihistamine.
- Use: Trazodone is clinically proven to treat anxiety and behavioral disorders in dogs, including separation anxiety, whereas Benadryl has not been shown to effectively treat dog anxiety.
- Medication type: Trazodone is a prescription medication used off-label in pets, while Benadryl is an over-the-counter medication intended for treating allergic reactions in humans.
-
Side effects: Trazodone may cause sedation as part of its calming effect, while Benadryl primarily causes drowsiness, which may make dogs appear calmer without addressing anxiety directly.
Trazodone vs. Benadryl: Which is better for anxiety in dogs?
Which is best for your dog? Ultimately, it depends on their type and level of anxiety. If you're looking for an effective allergy medicine for your dog to prevent them from scratching, choose Benadryl. However, trazodone is best if you're looking for a medication to help treat their anxiety.
How to treat anxiety in dogs
Some pet parents use Benadryl to calm their dogs during travel, vet visits, and other events. However, anecdotal evidence can't paint a clear picture of just how effective Benadryl truly is. While this medication can make your dog drowsy, it can't necessarily calm them down if they feel intense anxiety. Instead, they'll be drowsy and anxious.
Finding the best anxiety treatment for your dog is crucial. There are so many different types of dog anxiety that can affect their quality of life, so you must consult a vet to help you find the best solution for your pet. For example, many dogs benefit from behavioral training to help them feel more confident in new situations and environments. Meanwhile, some dogs are naturally more anxious due to a history of abuse or negligence and may have to be on anxiety medication for their entire lives.
Finding the best treatment can help your dog live a happy, healthy life without debilitating anxiety that prevents them from enjoying their favorite activities. Working with a vet or veterinary behaviorist can help reduce your dog's anxiety, improve their quality of life, and help them cope with stress more easily.
Other types of sedatives for dogs
Trazodone and Benadryl aren’t the only options for managing anxiety or sedation in dogs. Depending on your dog’s condition, anxiety level, and overall health, a veterinarian may recommend alternative medications or supportive treatments. Here are some other common anxiety treatments for dogs.
Gabapentin
Gabapentin is often used to manage chronic pain and anxiety, particularly when nerve-related discomfort contributes to stress. It has calming, sedative effects and is frequently prescribed alongside other medications, such as trazodone or NSAIDs, to support dogs with anxiety or medical-related stress.
Benzodiazepines
Benzodiazepines, such as diazepam or alprazolam, are fast-acting anti-anxiety medications commonly used for short-term or situational anxiety, including noise phobias or travel stress. While effective, they’re typically reserved for specific cases due to the risk of sedation, dependence, or behavioral changes.
Drugs for long-term anxiety issues
For dogs with ongoing or severe anxiety, vets may prescribe daily medications like SSRIs or other antidepressants. These drugs are designed for long-term use and often paired with behavioral training to help manage conditions such as separation anxiety or chronic fear-based behaviors.
Get a prescription for your dog’s long-term anxiety issues online with Dutch.
Injectable sedation
Injectable sedatives are used in clinical settings, such as veterinary visits or medical procedures. These medications are administered by professionals and are not intended for at-home use, but they can help keep dogs calm and comfortable during stressful or painful treatments.
Natural remedies for dog anxiety
Some pet owners explore natural calming options, including supplements, pheromone diffusers, or calming treats. While these remedies may help mild anxiety, they’re not a replacement for prescription medications in certain cases and should be discussed with a vet to ensure safety and effectiveness.
Choosing the right anxiety or sedation option isn’t always straightforward. Dutch connects you with licensed veterinarians online who can offer personalized behavioral advice, evaluate anxiety symptoms, and help determine whether prescription medication, training strategies, or a combination of both is best for your dog.
Talk to a licensed vet to find the right treatment for your dog.

Keep your dog calm with Dutch
Trazodone and Benadryl have both been used to help calm dogs. However, no clinical studies currently prove that Benadryl is effective in treating anxiety in dogs. On the other hand, trazodone has been proven effective, and many pet parents use it to help their dogs stay calm in a variety of situations.
Considering trazodone vs. Benadryl for dogs? Consult a Dutch vet today. We specialize in behavior issues and anxiety to help you find the best treatment plan for your dog based on their health, type of anxiety, and fear levels. If appropriate, we can give you a trazodone prescription online to reduce your dog's anxiety.
Discover why Dutch is the go-to choice for convenient, licensed veterinary care online.
Trazodone vs. Benadryl FAQs
What is the safest sedative for dogs?
The safest option is always the one prescribed by a veterinarian after evaluating your dog, as some sedatives can interact with other medications or worsen existing conditions. In mild cases, behavioral training or non-prescription calming aids may be sufficient, while more severe anxiety or medical procedures may require prescription sedation.
Medications like trazodone, gabapentin, and certain benzodiazepines are commonly prescribed and considered safe when used under veterinary guidance and at the correct dose.
What works better – trazodone or Benadryl?
Trazodone is a proven anxiety medication for dogs, while Benadryl is an antihistamine that can treat allergies and cause drowsiness. While some pet parents report that Benadryl has helped their dogs through stressful situations, there's not enough clinical evidence to prove that this allergy medicine is an effective anxiety treatment.
Instead, if you want to help your dog's anxiety, most vets recommend trazodone because it's effective and fast-acting. That said, several other anxiety treatments are available, so it's best to discuss your dog's situation with your vet to find the best solution.
Is trazodone the same as Benadryl?
No, trazodone is not the same as Benadryl. Trazodone is a prescription anxiety medication for dogs, while Benadryl is an over-the-counter antihistamine. There are no studies demonstrating the effectiveness of Benadryl for treating dog anxiety, but because it induces drowsiness, it may help dogs fall asleep faster and stay relaxed in stressful situations.
Always consult your vet before giving your dog any medication. There are some dogs that shouldn't take Benadryl or trazodone. In addition, when you talk to your vet, be sure to discuss any other medications, supplements, or vitamins your dog takes to ensure there won't be any potentially dangerous interactions.
How long will trazodone keep my dog calm?
Trazodone can take two or more hours to work in some dogs. However, its effects can last anywhere from six to 12 hours. Ultimately, you won't know how long Trazodone will keep your dog calm until your vet gives you a treatment plan. Then, they'll most likely have you monitor your dog to determine onset and duration and tweak the dosage accordingly.
How do I know if my dog is anxious?
Common signs of anxiety in dogs include excessive barking or whining, pacing, trembling, panting, destructive behavior, and attempts to escape. Some dogs may also show subtle signs such as hiding, yawning, lip licking, or changes in appetite. If these behaviors appear consistently or worsen during certain situations, anxiety may be the underlying cause.
Can I give my dog Benadryl and trazodone together?
Benadryl and trazodone can sometimes be given together, but only under veterinary guidance. Both medications can cause drowsiness, and combining them may increase sedation or coordination issues. The veterinarians at Dutch can confirm whether the combination is safe for your dog and determine the appropriate dosing.
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References
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Gruen, Margaret E, et al. "Use of Trazodone to Facilitate Postsurgical Confinement in Dogs." Journal of the American Veterinary Medical Association, U.S. National Library of Medicine, 1 Aug. 2014, https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4414248/.
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