By Rania Gollakner, BS, DVM, MPH

What is trazodone?

Trazodone (brand name Desyrel®, Oleptro®) is a serotonin antagonist/reuptake inhibitor (SARI) antidepressant that is used to treat behavioral disorders, especially anxiety- or phobia-related in dogs (e.g., separation anxiety, noise phobia such as fireworks or thunderstorms, veterinary visits, hospitalization, and travel). It is frequently used as a supplemental therapy in pets that do not respond to conventional therapies.

Its use in cats and dogs to treat behavioral disorders is 'off label' or 'extra-label'. Many drugs are commonly prescribed for off label use in veterinary medicine. In these instances, follow your veterinarian’s directions and cautions very carefully as their directions may be significantly different from those on the label.

How is trazodone given?

Trazodone is given orally (by mouth) in the form of a tablet. It may be given with food or on an empty stomach. If your pet vomits or acts sick after receiving the medication on an empty stomach, try giving the next dose with food or a small treat.

This medication will take effect quickly, in about 1 to 2 hours, when used for short-term stress relief, but for long-term treatment, this medication can take a few weeks before full effects are observed.

What if I miss giving my pet the medication or my shipment is late?

If you miss a dose, give it when you remember, but if it is close to the time for the next dose, skip the dose you missed and give it at the next scheduled time, and return to the regular dosing schedule. Never give your pet two doses at once or give extra doses.

Are there any potential side effects?

Trazodone is a short-acting drug. Side effects in dogs are not well documented but are generally mild if present. Possible side effects include dilated pupils, sedation, lethargy, vomiting or gagging, colitis (inflammation of the colon), ataxia (loss of muscle control), priapism (persistent and painful erection of the penis), arrhythmias, increased anxiety, increased appetite, and aggression.

When trazodone is used with other serotonergic drugs, serotonin syndrome is possible. This includes signs such as vomiting, diarrhea, seizures, hyperthermia (elevated body temperature), sensitivity of the skin, depression, dilation of pupils, vocalization, blindness, excessive salivation, difficulty breathing, loss of control of movements, paralysis, disorientation, coma, and death.

This short-acting medication should stop working within 24 hours, although effects can be longer in pets with liver or kidney disease.

Are there any risk factors for this medication?

Trazodone is not recommended in pets hypersensitive to it or those using MAO inhibitors. This medication should be used with caution in pets with severe heart disease or liver or kidney impairment. Pets with angle-closure glaucoma should not use this medication. Animal studies have shown an adverse effect on the developing fetus at very high doses, so the risks of using this medication in pregnant pets versus the benefits will be considered carefully by your veterinarian.

Are there any drug interactions I should be aware of?

The following drugs should be used with caution when given with trazodone: antihypertensive drugs, aspirin, azole antifungals, cisapride, CNS depressants, digoxin, diuretics, fluoroquinolones, macrolide antibiotics, monoamine oxidase inhibitors, metoclopramide, NSAIDs, ondansetron, phenothiazines, SSRI antidepressants, and tramadol.

Be sure to tell your veterinarian about any medications (including vitamins, supplements, or herbal therapies) that your pet is taking.

Is there any monitoring that needs to be done with this medication?

There is no specific monitoring that needs to be done while your pet is taking this medication. Your veterinarian may monitor your pet to be sure that the medication is working.

How do I store trazodone?

Store this medication between 20°C – 25°C (86°F – 77°F). Keep in an airtight container and protect from light.

What should I do in case of an emergency?

If you see signs of serotonin syndrome call your veterinary office. If you suspect an overdose or an adverse reaction to the medication, call your veterinary office immediately. If they are not available, follow their directions in contacting an emergency facility.

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