Torasemide

Torasemide In Dogs & Cats: Uses, Dosage and Side Effects

Overview

• Torasemide is a loop diuretic that inhibits the Na+/K+/Cl– co-transporter in the thick ascending limb of the loop of Henle.
• Results in loss of sodium, potassium, chloride, and water in urine; potassium excretion is lower compared to furosemide.
• Increases the excretion of calcium, magnesium, and hydrogen, and enhances renal blood flow and glomerular filtration rate.
• Exhibits an antialdosteronergic effect by dose-dependent inhibition of receptor-bound aldosterone.
• The diuretic effect of torasemide is approximately 20 times that of furosemide with current veterinary products (10 times with human generic torasemide products).

Uses of Torasemide

• Torasemide is authorized to treat the clinical signs of congestive heart failure in dogs (UpCard).

Dose of Torasemide in Dogs and Cats

Dogs:

• 0.1 to 0.6 mg/kg p.o. q24h.
• Anecdotally, doses are calculated and then divided into q12h intervals.
• Most dogs will be stabilized at less than or equal to 0.3 mg/kg p.o. q24h.
• The dose should be titrated up/down in 0.1 mg/kg p.o. increments.

Cats:

• Replace furosemide p.o. with torasemide p.o. at a daily dose that is 1/20th of the total daily furosemide dose divided q12–24h.

Side Effects of Torasemide in Dogs and Cats

• Common adverse effects in animals include hypokalemia, hypochloremia, hypocalcemia, hypomagnesemia, hyponatremia, dehydration, polyuria/polydipsia, and prerenal azotemia.
• Animals with pre-existing cardiac conditions like severe pulmonary hypertension, low-output heart failure, hypertrophic cardiomyopathy, pericardial or myocardial disorders, and cardiac tamponade may experience a marked reduction in cardiac output.
• Other adverse effects reported in humans include ototoxicity, blurred vision, GI disturbances, leukopenia, anemia, weakness, and dermatological reactions.

Contraindications of Torasemide in Dogs and Cats

• Dehydration and anuria.

Some Notes:

• Torasemide, compared to furosemide at equivalent doses, has higher bioavailability and a longer duration of action (12 hours, peak effect at 2 hours in dogs, and 4 hours in cats).
• Results in less kaliuresis and calciuresis than furosemide.
• Dogs receiving torasemide for 14 days experienced less diuretic resistance and greater increases in BUN compared to those receiving furosemide.
• Long-term therapy should aim for the lowest effective dose to control congestive heart failure signs.
• Torasemide has been used to treat edema associated with hepatic cirrhosis and renal failure in humans.
• Use with caution in patients with severe electrolyte depletion, hepatic failure, renal failure, and diabetes mellitus.
• Torasemide is not authorized for use in cats, unlike furosemide.