Furosemide Dosage for Cats: What Every Pet Owner Should Know

If your vet prescribed furosemide, you already know it’s a powerful diuretic that helps cats get rid of excess fluid. That’s why it’s used for heart disease, kidney problems, or pulmonary edema. The trick is to give the right amount – too little won’t work, too much can be dangerous.

How to Calculate the Right Dose

Veterinarians usually start with a dose of 1 to 2 mg per kilogram of body weight once or twice a day. For a typical 4‑kg (9‑lb) cat, that works out to about 4‑8 mg per dose. Most pharmacies sell furosemide tablets in 20 mg strengths, so your vet may split a tablet or use a liquid formulation to hit the exact number.

Several factors can shift the dose up or down:

• Kidney function: If the kidneys are weak, the vet may lower the dose to avoid dehydration.
• Heart condition severity: Cats with severe congestive heart failure often need the higher end of the range.
• Age and overall health: Older cats or those on other meds may need a more cautious approach.

Always follow the vet’s exact instructions. If the prescription says "give 0.5 tablet twice daily," don’t guess – use a pill splitter or ask the pharmacy for a pre‑split dose.

What to Watch For After Giving Furosemide

Furosemide works fast, so you’ll notice more pee within a few hours. That’s the goal, but it also means you need to keep an eye on a few things:

• Dehydration: Check that your cat is still drinking water. If you see dry gums, sunken eyes, or excessive lethargy, call the vet.
• Electrolyte loss: Low potassium can cause muscle weakness or heart rhythm changes. Some vets add a potassium supplement if the dose is high.
• Urination frequency: A big increase is normal, but if your cat stops urinating, that’s an emergency.

Record the daily urine output if you can. A simple way is to note how many times your cat uses the litter box and any changes in the amount of wetness. This data helps the vet adjust the dose quickly.

Another tip: give furosemide with food or a small treat if your cat’s stomach is sensitive. The drug can cause mild stomach upset in some cats, and a bit of food can smooth that out.

Never stop the medication abruptly, even if your cat seems better. Stopping suddenly can cause fluid to build up again, putting the heart and lungs under stress. If you need to pause or change the schedule, call the clinic first.

Finally, keep all follow‑up appointments. The vet will likely recheck blood work, electrolytes, and heart function after a week or two on the new dose. Those checks are the best way to make sure the dosage stays safe and effective.

Bottom line: furosemide can be a lifesaver for cats with fluid‑related issues, but it demands careful dosing and close monitoring. Stick to the vet’s numbers, watch your cat’s water intake and bathroom habits, and report any odd signs right away. With that approach, you’ll give your feline friend the best chance for a smoother, healthier recovery.