Diuresis is usually complete within 6–8 hours of oral administration, but there is significant variation between individuals. Adverse effects
Furosemide also can lead to gout caused by hyperuricemia. Hyperglycemia is also a common side effect. The tendency, as for all loop diuretics, to cause low serum potassium concentration (hypokalemia) has given rise to combination products, either with potassium or with the potassium-sparing diuretic amiloride (Co-amilofruse). Other electrolyte abnormalities that can result from furosemide use include hyponatremia, hypochloremia, hypomagnesemia, and hypocalcemia.In the treatment of heart failure, many studies have shown that the long-term use of furosemide can cause varying degrees of thiamine deficiency, so thiamine supplementation is also suggested.Furosemide is a known ototoxic agent generally causing transient hearing loss but can be permanent. Reported cases of furosemide induced hearing loss appeared to be associated with rapid intravenous administration, high dosages, concomitant renal disease and coadministration with other ototoxic medication. However, a recently reported longitudinal study showed that participants treated with loop diuretics over 10 years were 40% more likely to develop hearing loss and 33% more likely of progressive hearing loss compared to participants who did not use loop diuretics. This suggests the long-term consequences of loop diuretics on hearing could be a more significant than previously thought and further research is required in this area. Other precautions include: nephrotoxicity, sulfonamide (sulfa) allergy, and increases free thyroid hormone effects with large doses. Interactions
Furosemide has potential interactions with these medications:
Aspirin and other salicylates
Other diuretics (e.g. ethacrynic acid, hydrochlorothiazide)
Synergistic effects with other antihypertensives (e.g.
Although it increases circulation to the kidneys, it does not help kidney function, and is not recommended for kidney disease.It is also used to treat congestive heart failure (pulmonary edema, pleural effusion, and/or ascites) in cats and dogs. It can also be used in an attempt to promote urine production in anuric or oliguric acute kidney failure. Horses
Furosemide is injected either intramuscularly or intravenously, usually 0.5-1.0 mg/kg twice/day, although less before a horse is raced. As with many diuretics, it can cause dehydration and electrolyte imbalance, including loss of potassium, calcium, sodium, and magnesium. Excessive use of furosemide will most likely lead to a metabolic alkalosis due to hypochloremia and hypokalemia. The drug should, therefore, not be used in horses that are dehydrated or experiencing kidney failure. It should be used with caution in horses with liver problems or electrolyte abnormalities. Overdose may lead to dehydration, change in drinking patterns and urination, seizures, gastrointestinal problems, kidney damage, lethargy, collapse, and coma. Furosemide should be used with caution when combined with corticosteroids (as this increases the risk of electrolyte imbalance), aminoglycoside antibiotics (increases risk of kidney or ear damage), and trimethoprim sulfa (causes decreased platelet count). It may also cause interactions with anesthetics, so its use should be related to the veterinarian if the animal is going into surgery, and it decreases the kidneys ability to excrete aspirin, so dosages will need to be adjusted if combined with that drug. Furosemide may increase the risk of digoxin toxicity due to hypokalemia.