Mar Vista Animal Medical Center

3850 Grand View Blvd.
Los Angeles, CA 90066




 (for veterinary information only)


50 MG, 100 MG, 150 MG, 300 MG


Anxiety and depression are unfortunately common human problems with pharmaceutical solutions in abundance. People want to be free from worry and stress without suffering drowsiness, addiction, or any other untoward side effects thus new medications are nearly constantly in development. Many such medications, trazodone included, work by increasing serotonin levels in the brain. Increasing serotonin in the brain means less anxiety and a happier attitude. By inhibiting the brain’s system for removing used serotonin, serotonin 2A antagonist/reuptake inhibitors like trazodone cause serotonin to linger, lasting longer. The more serotonin we have in our brains, the less anxiety, obsession, and depression we get. Trazodone is used to treat depression in humans and is used to treat anxiety in dogs and cats.


Trazodone is typically used to manage short-term canine and feline anxiety issues. It has been useful in helping orthopedic patients stay relaxed during confinement/recovery periods as well as in other situations where anxiety is a problem: travel, visit to the vet, fireworks or thunderstorms etc. It is frequently combined with other anxiety medications to enhance effects.

Most dogs experience anxiety relief within 2 hours of administration. This can be variable, however, as can duration of action so it is important to test the medication before the anticipated event so as to know what to expect. Often trazodone is given at a lower dose for a couple of days to reduce the potential for upset stomach side effects.

Trazodone can be used long term (generally given twice a day with or without food) or on an as needed basis.


When trazodone use has been studied in dogs, 80% of dogs using trazodone had experienced no negative side effects. For the dogs that did experience side effects, the mostly seen effects involved aggressive food seeking, sedation, nausea and diarrhea. Some experts recommend using a lower dose of trazodone for a few days to acclimate the patient and help avoid side effects.

The most serious potential side effect of trazodone is something called “serotonin syndrome” so we will take a moment to review it. Serotonin syndrome is a reaction that occurs when brain levels of serotonin get too high. Elevated heart rate, tremors/shivering, dilated pupils, difficulty breathing, elevated body temperature, or high blood pressure can all be signs of serotonin syndrome. Cyproheptadine acts by reducing brain serotonin levels and can be used to reverse serotonin syndrome. Serotonin syndrome is an unlikely effect of trazodone but it becomes more likely when trazodone is combined with other serotonin enhancing drugs so it is important to be able to recognize it.

When combined with medications that lower blood pressure, trazodone use can drop blood pressure further, potentially too low.


As mentioned, the risk of serotonin syndrome is increased when other serotonin enhancing drugs are used with trazodone. Fluoxetine and clomipramine would be examples of such medications. MAO inhibitors such as selegiline and amitraz (a tick control product) can also increase the risk of serotonin syndrome as can concurrent use with the anti-nausea medication metoclopramide. Concurrent use of trazodone and tramadol can increase the risk of serotonin syndrome.

If trazodone is combined with other medications that list sedation as a potential side effect, the chance of tranquilization/sedation will be increased.


There is a risk of increased bleeding tendency when trazodone is combined with Non-Steroidal Anti-Inflammatory Drugs (NSAIDs).

Trazodone blood levels are increased when trazodone is combined with phenothiazines (such as acepromazine), macrolide antibiotics (such as erythromycin) or with the “azole” antifungal drugs (such as ketoconazole).


Trazodone can be given with or without food. Nausea side effects, if they occur, are mitigated by giving trazodone with food.

If a dose is accidentally skipped, do not double up next time. Simply pick up the regimen at the next scheduled dose.

Store trazodone tablets at room temperature, protected from light.

Trazodone should not be used in patients in heart failure, liver failure or kidney failure.

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Page posted: 2/13/2021