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
150 MG AND 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. In earlier times, the benzodiazepine family of drugs (of which Valium® is a member) were the predominant anxiety medications but their use was complicated by sedative side effects and chemical dependence. These unacceptable side effects drove researchers to seek a better solution.
Because the development of drugs that alleviate these conditions is ongoing, there are many medications on the market for these uses currently. Many, trazodone included, work by increasing serotonin levels in the brain.

Serotonin is a brain neurotransmitter associated among other things with mood elevation and reduced aggression. 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 used to manage 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.


The most common side effects in dogs are nausea, diarrhea, sedation/lethargy, and excessive hunger. In most cases, these are mild. Sometimes a lower dose is used to acclimate the patient so as to avoid nausea side effects.

The most serious potential side effect of trazodone is something called “serotonin syndrome” some 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.


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.

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 is best given on an empty stomach but if nausea is an issue, it may be given with food.

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

Page posted: 5/11/2018