What are the early signs of antidepressant ingestion in dogs and cats?

Common early signs include lethargy or over-excitement, vomiting, diarrhoea, changes in heart or respiratory rate, and tremors or seizures. Seek veterinary care promptly if any of these are obvious.

What should I observe at home after a suspected ingestion?

Record the time of suspected exposure and when symptoms began, video any abnormal behaviour, keep the medication packaging, and note the number of vomiting episodes to help your vet assess the situation.

What tests will the vet typically perform when I bring my pet in?

The vet will perform a thorough physical examination and may order blood tests, urinalysis, an ECG, or imaging studies to assess the extent of toxicity.

Can I monitor my pet at home first if I suspect poisoning?

If your pet shows no symptoms initially, you may contact your vet for guidance on home monitoring. However, if vomiting, tremors, lethargy, or breathing changes occur, seek veterinary care immediately.

How much do the tests and treatment usually cost?

Costs vary by clinic and region — ask your vet for an estimate before proceeding.

Disease Guide

SSRI/SNRI Antidepressant Poisoning in Dogs & Cats: Symptoms, Diagnosis & Treatment [2025]

SSRI/SNRI antidepressant poisoning can cause serotonin syndrome, with symptoms including agitation, fever, and rapid heart rate — prompt veterinary care is essential.

Take 1 minute to check the symptoms first

Last updated: 2026/01/05

Pethealthmap Editorial Team

Sources: PPH, AVMA, National Taiwan University Veterinary Hospital

When to See a Vet

Seek Emergency Care Immediately

•Continuous, uncontrollable seizures
•Prolonged unconsciousness or unresponsive to stimulation
•Obvious difficulty breathing or severe respiratory distress

Schedule a Clinic Visit Soon (within 24–72 hours)

•Repeated vomiting or persistent diarrhea lasting more than one day
•Marked agitation or ongoing restlessness and anxiety
•Unsteady gait or recurring tremors that interfere with movement

01What Symptoms Indicate a Problem?

After ingesting SSRIs or SNRIs, dogs and cats commonly show behavioural changes, gastrointestinal upset, and neurological signs — severe cases can be life-threatening.

Behavioural changes: may include lethargy, over-excitement, or agitation
Repeated vomiting, sometimes with visible pill fragments in the vomit
Diarrhoea or loose stools, occasionally with blood or mucus
Rapid heart rate or changes in breathing rate warrant close attention
Tremors, seizures, or brief episodes of altered consciousness
Unsteady gait, loss of balance, or a marked decrease in activity
Seek emergency veterinary care immediately if symptoms are severe or rapidly worsening

Seek emergency care immediately if you notice the following symptoms:

⚠️ Continuous seizures or loss of consciousness
⚠️ Difficulty breathing or obvious respiratory distress
⚠️ Excessively rapid heart rate or sudden collapse with no response

02How to Assess the Situation at Home: Observation Tips and When to Go to Emergency

Observing and recording key details at home helps your vet quickly assess the severity of poisoning and prioritise treatment.

Note the time symptoms started and when the suspected ingestion occurred
Record a video of your pet's behaviour or any seizures on your phone to show the vet
Track the number of vomiting episodes and describe the appearance and content of the vomit
Monitor changes in stool consistency and urination frequency
Watch for changes in appetite, water intake, and activity level
Bring the medication packaging, any remaining tablets, or the prescription to the clinic for reference
If symptoms worsen or emergency signs appear, go to an emergency clinic immediately

03How Will the Vet Diagnose the Problem? Common Tests and Procedures

Upon arrival, the vet will perform a thorough physical examination and may order blood tests, an ECG, and other diagnostics as needed.

Full physical examination

assessing mentation, heart rate, respiratory rate, and neurological reflexes

Blood tests

complete blood count and biochemistry panel to evaluate liver, kidney, and other organ function

Urinalysis

to detect metabolic or excretion abnormalities

ECG or continuous cardiac monitoring

to detect arrhythmias or conduction abnormalities

Imaging (X-ray, CT/MRI) if needed to assess complications

Identifying the drug type and packaging to help estimate the dose ingested

Hospitalisation for monitoring or referral to a specialist centre depending on severity

04Treatment and Aftercare: Medications, Dietary Adjustments, and Home Care

Treatment centres on supportive care and monitoring, focusing on stabilising vital signs and watching for any organ or behavioural changes.

Acute phase management focuses on supportive care to maintain stable breathing and circulation
Decontamination measures such as activated charcoal may be used to reduce absorption, at the vet's discretion
Seizures or cardiac arrhythmias will be managed with targeted treatment and continuous monitoring
Follow-up visits after discharge to monitor liver and kidney function and any behavioural or neurological changes
Home care typically includes short-term fasting and close observation for symptom changes
If symptoms recur or do not improve, specialist referral or further outpatient follow-up is recommended

05What to Prepare Before the Vet Visit: Key Information to Help Your Vet Act Quickly

Write down when symptoms started and how they were first noticed

Collect a vomit or stool sample in a clean container to bring to the clinic

Bring the medication packaging, a list of all current medications, and any prescription records

Take videos and photos so the vet can review your pet's behaviour or seizure activity on the spot

Note what your pet ate most recently and any supplements they have access to

If serious poisoning is suspected, contact a veterinary clinic experienced in toxicology cases before you arrive

This content is for reference only and cannot replace a professional veterinary diagnosis. If your pet shows signs of illness, please seek veterinary care promptly.