Description

Furosimide is the most commonly used diuretic in the horse. It increases urine production and decreases the amount of fluid within tissues and organs of the horse's body. It also acts upon the kidneys, causing increased excretion of electrolytes and water.

Usage

Furosemide is used to treat pulmonary edema, some allergic reactions, and congestive heart failure.  Some veterinarians prescribe furosemide for racehorses because it is thought to prevent or diminish the severity of exercise-induced pulmonary hemorrhage or bleeding from the lungs.  This use is controversial.

Dosage and Administration

Furosemide
Method	Dosage (click row for calculator)	Concentration	Period	Duration
Oral	1-2 mg/lb	25 mg/tablet	Once or twice daily at 6 to 8 hour intervals	Until desired results are achieved
Oral	1-2 mg/lb	50 mg/tablet	Once or twice daily at 6 to 8 hour intervals	Until desired results are achieved
Intravenous or Intramuscular injection	0.5-1 mg/lb	50 mg/ml	Once or twice daily at 6 to 8 hour intervals	Until desired results are achieved
Notes: Federal law restricts this drug to use by or on the order of a licensed veterinarian. Extra-label use of drugs in treating animals is allowable only by licensed veterinarians within the context of a valid veterinarian-client-patient relationship, and does not include drug use in treating animals by the layman (except under the supervision of a licensed veterinarian). Calculator is for educational purposes only. Follow your veterinarian's instructions regarding use of this, or any medication.

Side Effects

Side effects include dehydration and loss of electrolytes.  In some species, furosemide may negatively impact hearing and balance.

Precautions

Furosemide should not be given to animals with kidney failure, animals in a state of dehydration, or those likely to become dehydrated.  It should be used with extreme caution in animals with electrolyte abnormalities or liver disease.

Furosemide is usually combined with other supportive cardiac drugs in therapy for congestive heart failure.

Use of furosemide during pregnancy has been shown to cause fetal deformities in other species.  For that reason, furosemide should not be used during pregnancy, and only with extreme care during lactation.

Furosemide should be used with extreme care in foals because of potential problems with dehydration and electrolyte abnormalities.

Furosemide should not be used in older horses with kidney and liver functions that are not normal.

Use of furosemide is FDA approved for horses.  U.S. law restricts this drug to use by or on the lawful written or oral order of a licensed veterinarian.

In those states that permit furosemide in racehorses, the dose and administration are highly regulated and the particular regulatory group should be consulted before the drug is used.

Interactions

When furosemide is given with corticosteroids, a greater risk of electrolyte abnormalities, including low blood potassium and calcium, exists.

Doses of aspirin may need to be lowered when furosemide is given.

Furosemide can change the response to a number of drugs used during general anesthesia.  It is important that the surgeon is informed of the use of furosemide and of any other medications if the animal is to undergo surgery.

Furosemide increases the risk of kidney and ear damage from aminoglycoside antibiotics.

Combined use of furosemide and trimethoprim sulfa may cause a decrease in platelet count.

Overdose

Drug overdose with furosemide may cause dehydration and electrolyte imbalances.  Chronic overdose may cause kidney damage.  Signs include increased or decreased thirst and urination, lethargy, increased heart rate, gastrointestinal distress, seizures, collapse, and coma.