What should I do if my pet may have ingested ivermectin?

If ingestion is suspected, record the time and amount (if known), photograph the packaging or medication, and immediately contact your vet or an emergency animal clinic. Bring any samples and video footage to aid assessment.

What are the common symptoms of ivermectin toxicity?

Common signs include changes in behaviour and alertness (lethargy, reduced responsiveness), vomiting, unsteady gait, muscle tremors, and visual disturbances. Seek immediate veterinary care if breathing difficulties or loss of consciousness occur.

What should I bring to the clinic?

Bring a record of when symptoms first appeared, a symptom timeline, a list of recent medications and doses, any drug packaging or vomit samples, and video or photos — this will help speed up diagnosis and treatment.

Is follow-up care needed after treatment?

Yes. In most cases, blood tests or imaging follow-up is needed alongside monitoring of alertness, appetite, and bowel and bladder changes. Return to the clinic promptly or consult your vet if symptoms return or worsen.

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

Ivermectin & Macrocyclic Lactone Toxicity in Dogs & Cats: Symptoms, Diagnosis & Care [2025]

Ivermectin toxicity is common in breeds with MDR1/ABCB1 gene mutations (such as Collies). It can cause blindness, tremors, and coma. Treatment is primarily supportive, and recovery may take several weeks. Genetic testing is recommended before use.

Take 1 minute to check the symptoms first

Last updated: 2026/01/05

PetHealthMap Editorial Team

Sources: AVMA, WSAVA, National Taiwan University Veterinary Hospital

When to See a Vet

Seek emergency care immediately

•Sudden collapse with prolonged unresponsiveness
•Severe respiratory distress with inability to breathe normally
•Gums or tongue turning purple-blue indicating clear oxygen deprivation

Schedule a clinic visit soon (within 24–72 hours)

•Persistent vomiting or repeated expulsion of food or fluid
•Markedly decreased activity with prolonged lethargy showing no improvement
•Unsteady gait or recurring episodes of trembling or shaking

01What symptoms indicate something is wrong?

Ivermectin and other macrocyclic lactone toxicities typically present with neurological and gastrointestinal signs, ranging from mild lethargy to severe neurological dysfunction.

Noticeably reduced energy, persistent lethargy, or sluggish responses
Frequent vomiting or a clear decrease in appetite and water intake
Unsteady gait, difficulty standing, or repeated falling
Trembling, muscle twitching, or tremors
Changes in breathing pattern, slowed heart rate, or laboured breathing
Temporary blurred vision, unresponsive eyes, or brief episodes of blindness

Seek emergency care immediately if you notice the following symptoms:

⚠️ Sudden collapse or prolonged loss of consciousness
⚠️ Obvious difficulty breathing or persistent severe gasping
⚠️ Gums or tongue turning blue-purple or showing clear signs of oxygen deprivation

02How to assess the situation at home? Key observations and emergency criteria

Keeping a detailed record of key changes at home helps the vet quickly assess the severity of toxicity and the progression of symptoms.

Note the time symptoms first appeared and when each symptom occurred
Record the number of vomiting episodes, what was in the vomit (blood or foreign material), and the timing
Film video of any gait abnormalities, tremors, or changes in awareness for the vet
Monitor and record appetite, water intake, and frequency and colour of urine and faeces
Observe changes in alertness (lethargy, reduced responsiveness, or agitation)

03How will the vet make a diagnosis? Common examination steps

After arrival, the vet will assess the severity of toxicity and any organ damage through a physical examination and necessary tests.

Full physical examination

neurological reflexes, pupil response, muscle tone, and mobility assessment

Blood and biochemistry panel

evaluate liver and kidney function and electrolyte abnormalities

Urinalysis

assess kidney function and detect metabolic abnormalities

Imaging (X-ray or CT/MRI if needed) to rule out other causes

Specialist referral or hospitalisation for vital-sign monitoring if required

04How to treat and care for your pet after diagnosis? Medications, diet, and care guide

Ongoing monitoring and follow-up tests are essential after treatment, along with supportive care at home to aid recovery.

The vet will provide symptomatic and supportive care, with hospitalisation for monitoring if necessary
Adjust diet at home and ensure access to fresh water and a quiet rest environment
Schedule regular follow-up visits for blood tests or imaging to monitor recovery
Monitor alertness, appetite, and toileting daily, and report any changes to the vet
If symptoms do not improve or recur, return to the clinic promptly or arrange specialist follow-up

05What should you prepare before seeing the vet? Key information to help the vet identify the cause quickly

Record the time symptoms first appeared, how they progressed, and a timeline of all related signs

List all recently used medications, topical treatments, dosages, and any packaging

If possible, bring vomit samples, drug packaging, or any suspected source material

Prepare and bring video footage (of gait abnormalities, vomiting, seizures, etc.) for the vet's reference

In an emergency, call the clinic in advance so they can prepare

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.