What should I do if my pet accidentally ate metformin?

Note the time of ingestion and the dose if known, take a photo of the packaging, and contact your vet or a veterinary poison control centre straight away. Go to an emergency clinic immediately if your pet shows any symptoms.

How will the vet diagnose metformin toxicity?

The vet will rely on clinical signs, blood glucose levels, a biochemistry panel, and urinalysis. Imaging or continuous monitoring may be added if complications are suspected.

How long does monitoring continue after treatment?

The acute phase may require hospitalisation for several hours to a few days. After discharge, follow-up blood and biochemistry checks are typically scheduled over days to weeks as directed by your vet.

Can metformin cause lasting harm to my pet?

Whether there are long-term effects depends on the severity of the toxicity and whether any organ damage occurred. Your vet will recommend appropriate follow-up testing to assess recovery.

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

Metformin Toxicity in Dogs & Cats: Symptoms, Diagnosis & Care [2025]

Metformin is a diabetes medication that can cause low blood sugar and lactic acidosis in pets if accidentally ingested — immediate veterinary attention is required.

Take 1 minute to check the symptoms first

Last updated: 2026/01/05

Pethealthmap Editorial Team

Sources: ASPCA, AVMA, National Taiwan University Veterinary Hospital

When to See a Vet

Seek Emergency Care Immediately

•Sudden collapse or prolonged loss of consciousness
•Difficulty breathing or shallow, rapid respirations
•Continuous or repeated involuntary seizures/convulsions

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

•Persistent or frequent vomiting that is difficult to control
•Noticeably decreased appetite or refusal to eat for several consecutive meals
•Significantly decreased activity level or reluctance to move

01What symptoms indicate something is wrong?

Metformin toxicity typically presents with gastrointestinal signs and altered mental status, and may be accompanied by dehydration or decreased energy.

Persistent lethargy or reduced responsiveness
Repeated vomiting or a noticeable increase in vomiting frequency
Diarrhoea or loose stools, potentially leading to dehydration
Marked decrease in appetite or refusal to eat several meals
Reduced activity level, reluctance to play or move around

Seek emergency care immediately if you notice the following symptoms:

⚠️ Sudden collapse or prolonged loss of consciousness
⚠️ Difficulty breathing or noticeably shallow, rapid, or irregular respirations
⚠️ Continuous or recurrent seizures or involuntary muscle twitching

02How do you assess the situation at home? Key observations and when to go to emergency

Before going to the clinic, you can observe and record key changes at home — this information helps your vet assess the situation much faster.

Note any changes in alertness and your pet's response to sounds or touch
Record the number of vomiting episodes, what the vomit looks like, and when they occurred
Track bowel movement frequency and stool consistency, including any blood or mucus
Observe how much your pet eats at each meal and whether it has refused food repeatedly
Watch for changes in urine output or difficulty urinating and make a note of these
Take short video clips or photos of vomiting or abnormal behaviour to show your vet
Bring all notes and photos to the appointment so the vet can assess your pet quickly

03How will the vet diagnose this? Common diagnostic tests

The clinic will use a physical examination together with blood, urine, and imaging tests to assess toxicity, metabolic status, and potential complications.

Physical examination

measuring vital signs and assessing neurological responses

Blood glucose and acid-base assessment

evaluating metabolic and energy status

Biochemistry panel

checking liver and kidney function and electrolyte levels

Urinalysis

looking for glucosuria and metabolic changes

Imaging (X-ray / CT if indicated)

ruling out other thoracic or abdominal problems

Continuous monitoring or specialist referral arranged when needed

04What happens after diagnosis? Treatment, diet, and home care guide

Treatment is primarily supportive and monitoring-focused; after discharge, blood values, diet, and activity recovery will need to be tracked.

Hospitalisation for observation and intravenous fluid support may be needed during the acute phase
Follow-up appointments for blood glucose and biochemistry monitoring as directed by your vet
Dietary adjustments with close observation of appetite, vomiting, and bowel movements
Keep your pet warm and limit strenuous activity during home recovery
Regular recheck visits to evaluate progress and determine whether long-term monitoring is needed
Contact your vet immediately if symptoms do not improve or worsen again

05What should you prepare before the vet visit? Key information to help the vet act quickly

Note when symptoms started, how they have changed, and in what order they appeared

List all current medications, supplements, and dietary additions

Bring photos or video of vomiting or unusual behaviour if available

Prepare a record of bowel movements: timing, frequency, and stool appearance

Write down what your pet has eaten recently and roughly how much

If possible, contact a clinic in advance that can perform blood tests and imaging

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.