Furosemide
Diuretics
View Brand Names (1)Dose and dosage
a) 500 mg once daily or 250 mg twice daily; 2 grams PO once daily.
Treatment not to exceed 48 hours post-partum (for udder edema). Package
Insert; Lasix®–Hoechst)
b) 2.2–4.4 mg/kg IV q12h (Howard 1986)
As a diuretic:
a) For adjunctive therapy for congestive heart failure: Initially, 1–2 mg/kg IM or IV q6–12h to control edema. Long-term therapy: 0.5–2 mg/kg PO or IM q8–12h (Mogg 1999)
b) For adjunctive therapy of acute renal failure: 2–4 mg/kg q6h (Jose- Cunilleras & Hinchcliff 1999) For epistaxis/EIPH prevention:
a) 500 mg (total dose) 4 hours prior to race. (Hinchcliff et al. 2009)
b) 250 mg IV 4 hours prior to racing (Foreman 1999)
• 2–6 mg/kg q8–12h (or as needed) IV, IM, SQ, or PO. A common initial dose when treating heart failure patients is 2 mg/kg q12h PO; then lower to 1–2 mg/ kg q12h PO.
• In acute cases in which intensive treatment is needed, administer 2 mg/kg IV followed by 2 mg/kg every 30 minutes until improvement is seen.
• CRI: 0.66 mg/kg bolus dose IV followed by 0.66 mg/kg/h for 8 hours. Alternatively, a dose of 2 mg/kg in 5% glucose can be infused over an 8-hour period IV.
• Start with 1 mg/kg; then increase as needed, within a range of 1–4 mg/kg q8–24h
IV, IM, SQ, or PO.
As a diuretic:
a) 0.05 mg/300 grams body weight IM twice daily (Note: Lories are very sensitive to this agent and can be easily overdosed) (Clubb 1986)
For most species:
a) 5 mg/kg IV or IM as needed (Gauvin 1993)
a) Rabbits: For CHF: 2–5 mg/kg PO, SC, IM or IV q12h; For pulmonary edema: 1–4 mg/kg IV or IM q4–6h (Ivey & Morrisey 2000)
b) Mice, Rats, Gerbils, Hamsters, Guinea pigs, Chinchillas: 5–10 mg/kg q12h (Adamcak & Otten 2000)
For adjunctive therapy for heart failure:
a) 2–3 mg/kg IM or IV initially for fulminant CHF; 1–2 mg/kg PO q12h for long-term maintenance therapy (Hoeffer 2000)
b) 1–4 mg/kg PO, SC, IM or IV 2–3 times a day (Williams 2000)
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Indicated for the treatment of ascites, udder edema, pulmonary congestion, renal failure, acute non-inflammatory tissue edema etc. It also helps to excrete poisons or drug overdose by increasing urine flow.
Contraindicated to animal anuria, hypersensitivity, or seriously depleted electrolytes.
Furosemide increase urine volume by reducing the efficiency of sodium resorbing processes and so increase water loss from the body.
Furosemide is a loop diuretic that inhibits the Na+/K+/2Cl–cotransporter in the ascending thick loop of Henle. It is often called a high-ceiling diuretic because it is more effective than other diuretics. Furosemide decreases the sodium, chloride, and potassium reabsorption from the tubule. Subsequently, these ions are retained in the renal tubule and presented to the distal nephron. Dilute urine is produced because water is retained in the tubule when it reaches the distal tubule. In addition, there is an associated urine loss of Mg2+ and Ca2+. An additional mechanism of action is via prostaglandin synthesis. Furosemide increases intrarenal prostaglandin production (e.g., PGI2), which increases renal blood flow. Synthesis of prostaglandins also may cause vasodilation in other tissues. Torsemide is another diuretic in the same class as furosemide. It has greater potency than furosemide and can be used in refractory cases.
Pharmacokinetics: The plasma half-life in animals is short (1.5–3 hours); therefore, this is a short-acting drug, with a maximum onset of effect of 1–2 hours and a duration of 2–4 hours. Oral absorption can be highly variable but in dogs is as high as 77%. SQ absorption is as high as other injectable routes. In horses, oral absorption is so low that this is not a viable method of administration.
ACE INHIBITORS (e.g., enalapril, benazepril): Increased risks for hypotension, particularly in patients who are volume or sodium depleted secondary to diuretics
AMINOGLYCOSIDES (gentamicin, amikacin, etc.): Increased risk for ototoxicity
AMPHOTERICIN B: Loop diuretics may increase the risk for nephrotoxicity development; hypokalemia
CORTICOSTEROIDS: Increased risk for GI ulceration; hypokalemia
DIGOXIN: Furosemide-induced hypokalemia may increase the potential for digoxin toxicity
INSULIN: Furosemide may alter insulin requirements
MUSCLE RELAXANTS, NON-DEPOLARIZING (e.g., atracurium, tubocurarine): Furosemide may prolong neuromuscular blockade
PROBENECID: Furosemide can reduce uricosuric effects
SALICYLATES: Loop diuretics can reduce the excretion of salicylates
SUCCINYLCHOLINE: Furosemide may potentiate
THEOPHYLLINE: Pharmacologic effects of theophylline may be enhanced when used with furosemide
Common side effects: Increased urination alkalosis, uric acid retention and may rarely produce acute gout, hyperglycemia & glycosuria.
Rare side effects: Diarrhea or constipation, weakness, collapse, head tilt, balance problems, electrolyte imbalance, lack of urine production, or a racing heart rate. Fluid & electrolyte (esp. hyponatremia) abnormalities, others included: ototoxicity, GI distress, hematologic effects, ototoxicity, weakness, & restlessness
Acute overdosage may cause electrolyte and water balance problems, CNS effects (lethargy to coma and seizures) and cardiovascular collapse. Treat supportively and symptomatically if necessary.
Can be used in Pregnancy and lactating animals. However, risk & necessity should be considered during administration in pregnant & lactating animal.
Do not mix with other medicines. Animals with pre-existing electrolyte or water balance abnormalities, impaired hepatic function.
Meat & Milk: Meat & milk must not be consumed up to 2 days after administration of this medicine. Egg: Not known.