Trazodone

By Lauren R. Forsythe, PharmD, MBA, DICVP; 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 carefully, as they 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 one to two hours, when used for short-term stress relief. 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 as soon as you remember, and then continue with the regular dosing schedule. However, if it is almost time for the next dose, skip the missed dose and resume the regular dosing schedule. Do not give the pet two doses at once.

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
  • 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
  • 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?

This medication should NOT BE USED in pets who:

  • are hypersensitive to it 
  • are using MAO (Monoamine oxidase) inhibitors
  • have angle-closure glaucoma

This medication should be USED WITH CAUTION in pets that:

  • have severe heart disease
  • have liver or kidney impairment
  • are pregnant

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?

Several medications should be used with caution when given with trazodone, including:

  • acepromazine
  • antihypertensive drugs
  • aspirin
  • azole antifungals
  • cisapride
  • CNS depressants
  • diuretics
  • fluoroquinolones
  • macrolide antibiotics
  • monoamine oxidase inhibitors
  • metoclopramide
  • NSAIDs
  • ondansetron
  • SSRI antidepressants 
  • tramadol

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

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

No specific monitoring is needed 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 and 25°C (86°F– 7°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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