Furosemide and Pets
Find out if Furosemide is toxic to dogs and cats.
Think your pet ate something toxic?
Call ASPCA Animal Poison Control Center: (888) 426-4435 or view emergency guide
Furosemide (commonly known by the brand name Lasix) is a powerful loop diuretic used in both human and veterinary medicine to treat fluid buildup, congestive heart failure, and high blood pressure. While veterinarians do prescribe furosemide for dogs and cats, accidental ingestion of human-strength tablets or an overdose of a pet's own prescription can rapidly lead to serious toxicity. The greatest dangers are dehydration and electrolyte imbalances—particularly low potassium and sodium—which can affect the heart, kidneys, and nervous system.
Pets may be exposed by chewing into a pill bottle, eating dropped tablets, or receiving too much of their own medication. Signs of poisoning can appear within 1–2 hours and include excessive thirst and urination, vomiting, diarrhea, weakness, lethargy, and loss of appetite. In severe cases, animals may develop low blood pressure, abnormal heart rhythms, collapse, or acute kidney injury. Cats are especially vulnerable because of their small size and sensitivity to dehydration and electrolyte shifts.
Prevention is essential. Store all furosemide products—human and veterinary—out of reach in a secure cabinet, and never leave pills on countertops or nightstands. Use a pill organizer or directly administer medications from the original bottle to avoid dosing errors. If you suspect your pet has eaten furosemide, seek veterinary help immediately; do not wait for symptoms to worsen and do not induce vomiting unless instructed by a professional.
Is Furosemide Toxic to Dogs?
Accidental ingestion or overdose of furosemide can cause rapid dehydration, dangerous electrolyte imbalances, low blood pressure, and kidney injury in dogs.
Is Furosemide Toxic to Cats?
Cats are sensitive to furosemide; even moderate overdoses can lead to severe dehydration, electrolyte disturbances, weakness, and potentially life-threatening complications.
Active Ingredients
- furosemide
Common Brand Names
- Lasix
Dosage Form
tabletoral solutioninjectable solution
Common Uses
- congestive heart failure
- pulmonary edema
- fluid retention
- high blood pressure
- kidney disease
Toxic Ingredients
- furosemide
Symptoms to Watch For
- excessive thirst
- increased urination
- dehydration
- lethargy
- weakness
- vomiting
- diarrhea
- loss of appetite
- low blood pressure
- collapse
- muscle cramps
- irregular heartbeat
- kidney failure
What If My Pet Was Exposed to Furosemide?
If your pet ingested furosemide, contact your veterinarian or a pet poison control center immediately. Bring the medication bottle and estimate how much was swallowed. Do not induce vomiting unless instructed by a professional.
Sources
Vet's Note
PetPilot provides general information for educational purposes. While we reference authoritative veterinary organizations, this page has not been individually reviewed by a veterinarian for your specific pet. Individual animals may react differently based on age, weight, breed, health conditions, and amount consumed. Always consult your veterinarian or a poison control center for personalized advice, especially if your pet is ill, injured, pregnant, nursing, or on medication.