Antidepressant Poisoning

One of the top 10 poisonings in dogs is caused by antidepressant medicines, such as selective serotonin reuptake inhibitors (SSRIs), tricyclics (TCAs), monoamine oxidase inhibitors (MAOIs), and novel antidepressants.

While there are many different kinds of antidepressants, they are all toxic to your dog if too much is ingested. Tricyclic antidepressants are potentially the most dangerous because they can affect the heart and central nervous system within minutes, and can be fatal if not treated right away, depending on the amount ingested and size of the dog. Cardiac arrhythmia, tachycardia, and bradycardia are common and have to be addressed as soon as possible after ingestion or it can be fatal. It is true that veterinarians sometimes prescribe antidepressants to dogs for certain conditions, but even with small doses, side effects can always occur.

Although antidepressant poisonings share many symptoms, they each have some unique symptoms that should be noted. This may help in determining which medication your dog has ingested if it is unknown. The symptoms can be separated by the type, or may be just general symptoms if the medication type is unknown:

General

• Abnormal heart rhythms
• Agitation
• Inability to urinate
• Bluish tinge to skin and mucous membranes
• Coma
• Confusion
• Constipation
• Dangerously low body temperature
• Depressed breathing
• Diarrhea
• Dry mouth
• Dilated pupils
• Fever
• High blood pressure
• Involuntary rhythmic movement of the eyes
• Lack of coordination
• Lethargy
• Low blood pressure
• Metabolic abnormalities
• Nausea
• Seizures
• Sudden muscular contractions
• Vomiting

SSRI

• Ataxia
• Extreme weakness
• High blood pressure
• Seizures
• Tachycardia
• Tremors
• Vomiting

 TCA

• Abnormal heart rhythms
• Aggression
• Anxiety
• Death
• Depression
• Disorientation
• Dyspnea
• Low blood pressure
• Lethargy
• Dilated pupils
• Pulmonary edema
• Rash
• Seizures
• Swelling of the tongue
• Tachycardia
• Tremors
• Hives
• Vasodilation
• Vocalizing
• Vomiting
• Weakness

MAOI

• Abnormal heart rhythms
• Coma
• Depression
• Fever
• High or low blood pressure
• Respiratory depression
• Restlessness
  
• Seizures
• Shock
• Tachycardia

Novel

• Seizures
• Tremors

Types

There are many types of antidepressant medications with different names, but the most common are selective serotonin reuptake inhibitors (SSRIs), tricyclics (TCAs), and monoamine oxidase inhibitors (MAOIs).

SSRI

• Citalopram (Celexa)
• Escitalopram (Lexapro)
• Fluoxetine (Prozac)
• Fluvoxamine (Luvox)
• Nefazodone (Serzone)
• Paroxetine (Paxil)
• Sertraline (Zoloft)
• Trazodone (Desyrel)

TCA

• Amitriptyline (Elavil)
• Clomipramine (Anafranil)
• Desipramine (Norpramin)
• Doxepin (Sinequan)
• Imipramine (Tofranil)
• Nortriptyline (Pamelor, Aventyl)
• Protriptyline (Vivactil)
• Trimipramine (Surmontil)

MAOI

• Isocarboxazid (Marplan)
• Phenelzine (Nardil)
• Selegiline (Emsam)
• Tranylcypromine (Parnate)

Novel

• Bupropion (Wellbutrin, Zyban)
• Duloxetine (Cymbalta)
• Maprotiline (Ludiomil)
• Venlafaxine (Effexor)

The causes of antidepressant poisoning usually includes one of these three things:

• Accidental ingestion (dog eating human’s medication)
• Giving too much medication (accidental double dosage or failure to follow proper instruction)
• Side effect of medication (rare)

Before examining your dog for diagnosis, your veterinarian will make sure they are stable. 

Depending on how long ago the antidepressant was ingested, your veterinarian may first treat your dog by trying to induce vomiting, and will use activated charcoal, which is effective even several hours after ingestion. Gastric lavage or enema will also be tried if necessary. The main thing is to remove the toxic chemicals from your dog’s system in any way possible. The veterinary team may go ahead and admit your dog to the hospital to provide IV fluids, medication, and observation.

During the examination, your veterinarian will check your dog’s heart rate, body temperature, respiration, and reflexes. It is important for you to give your veterinarian as much information as you have on your dog’s medical history, including vaccinations, recent illness or injury, and what kind of medicine you believe was ingested.

Your veterinarian will do some blood tests, such as a blood chemistry panel, blood gas analysis, and complete blood count (CBC). In addition, a urinalysis will help your veterinarian check that the kidneys are functioning properly. Your veterinarian will perform an EKG to monitor your dog’s heart rate and rhythm, and they may do an echocardiogram to see if the heart is pumping normally.

The recommended treatments for toxicity of any of these antidepressantscan include several things.

Detoxification

Inducing vomiting as soon as possible after ingestion of the drug, activated charcoal, lavage, and an enema to promote bowel movement. This will get rid of the chemicals in the body if done early enough.

Medications

Your veterinarian may also use sodium bicarbonate for acidosis, barbiturates or diazepam for seizures, and propranolol for tremors and irregular heart rate.

Supportive care

Depending on the severity of the poisoning, your dog will probably need to stay in the hospital for a minimum of 24 hours for observation. Fluids and any other supportive care as needed will be administered to help your dog recover.

Once you get home, make sure to find a place to store medications that your dog cannot get access to. In most cases, your dog will be fine within 24 to 48 hours after the drug wears off, but continue any medication that your veterinarian has given you, and be sure to call your veterinarian if you have any questions or concerns.

Got more questions about antidepressants poisoning in dogs? Chat with a vet professional today to get answers.

The cost of treating antidepressants poisoning can vary depending on how serious the condition is. A vet visit to induce vomiting typically costs between $300 and $500, while a short hospitalization can be anywhere from $600 to $2,000.