Furosemide
Salix, Lasix (veterinary and human) · generic furosemide
Furosemide is the diuretic that keeps fluid out of the lungs in dogs and cats with heart failure, and it is used for other fluid build-up. Veterinary versions are approved, and the human generic is the same drug; it is one of the cheapest tablets a pharmacy stocks.
What it is used for
Furosemide makes the kidneys remove salt and water quickly. In heart failure it is the drug that relieves the breathing difficulty caused by fluid in the lungs, and the dose is adjusted up and down by the vet against the animal’s breathing rate, which owners are taught to count at home while the pet sleeps. It is used with pimobendan and an ACE inhibitor in dogs, and in cats with heart disease.
Salix is a veterinary brand; the human tablets are the same drug. Increased thirst and urination are expected. Dehydration and low potassium are the risks, so blood tests are checked after dose changes, and torsemide is sometimes used when furosemide stops working well.
Safety points that differ from human use
- A pet on furosemide must always have water available; restricting water to reduce urination is dangerous.
- Vomiting, diarrhoea or refusing to drink can cause rapid dehydration on this drug; call the vet.
- Breathing faster than the rate the vet sets while resting, or at night, is an emergency sign that the dose is not enough.
- Tablets (human and veterinary)
- Oral solution (human)
- Injection (clinic use)
- Compounded liquids for cats
- 20, 40 and 80 mg human tablets
- 12.5 and 50 mg veterinary tablets
Why the cash price varies
Furosemide costs pharmacies almost nothing, so the cash price is the dispensing fee; the veterinary tablets are a little more expensive but come in a small strength useful for cats. Doses change often in heart failure, so several strengths and repeat fees are common.
How to pay less
- Ask the vet whether the human generic is suitable and which strength keeps the tablet count simple.
- Ask for a ninety-day prescription once the dose is stable, and whether furosemide is on the pharmacy’s flat-price list.
- Upload the prescription to Script Unlock so licensed pharmacies can quote. You pay the pharmacy directly.
Questions for your vet
- What resting breathing rate should I count, and what rate means I should call?
- What should I do if my pet vomits or will not drink?
- When are the kidney and potassium checks?
- How is the dose adjusted, and can I adjust it myself under instruction?
- Can I use the human generic tablet?
Rules on refills, transfers and controlled substances differ by state; see pharmacy rules by state.
How Script Unlock gets you a cash price for your pet’s furosemide prescription
Prices on this site come from pharmacies responding to a real prescription. We do not publish estimated, average or "typical" prices, because none of those would be your price.
- 1You upload your prescription
A photo of your your pet’s furosemide prescription prescription is enough. Nothing is sold on the site; you are asking pharmacies to quote.
- 2Licensed pharmacies respond
Pharmacies that Script Unlock has verified see the request and each can reply with its own cash price for your exact drug, strength and quantity.
- 3You choose and pay the pharmacy
You compare the responses, pick a pharmacy, and pay that pharmacy directly when you collect. Script Unlock never takes a patient payment and never sets the price.
Related pet medications
Sources
- FDA Approved Animal Drug Products (Green Book)
- Merck Veterinary Manual
- FDA Orange Book (approved generics and therapeutic equivalence)
- MedlinePlus drug information (National Library of Medicine)
Written by the Script Unlock editorial team from the sources above. Not yet reviewed by a veterinarian or veterinary pharmacist. Last checked 2026-10-03. Nothing here replaces your vet\u2019s directions; doses for animals are set by weight and species.
Script Unlock is a marketplace that lets licensed pharmacies quote a cash price on your prescription. It does not prescribe, dispense or sell medication, does not process patient payments, and does not give medical advice. Always follow the instructions of your prescriber and pharmacist and read the medication guide supplied with your medicine.