Pharmacotherapeutic group: Diuretics, furosemide
ATC Vet Code: QC03CA01
Pharmacodynamic properties
Furosemide is a derivate of sulfamoyl antranil acid and is a fast acting diuretic in humans and animals. It inhibits resorption of sodium and chloride ions in the kidneys mainly in the ascending Loop of Henle, but also in the proximal and distal renal tubules resulting in an increased water excretion. An isotonic or slightly hypotonic urine with unchanged or slightly acidic pH is produced. Excretion of potassium ions is only enhanced at very high doses.
Furosemide has no effect on carbonic anhydrase.
Pharmacokinetic particulars
Furosemide is absorbed rapidly mostly in the stomach and upper small intestine Maximum concentrations were measured at 1.1 hour after oral administration in cats and at 0.8 hours in dogs. After a mean oral dose of 5.2 mg/kg, Cmax in cats was 8.8 µg/ml. After a mean oral dose of 1.9 mg/kg, Cmax in dogs was 0.9 µg/ml.
Metabolism of furosemide is very limited. It is predominantly excreted via the kidneys, whilst the rest is excreted via the gastrointestinal tract. Elimination half-life was 3.7 hours in cats and 2.4 hours in dogs.