Furosemide

Furosemide is a widely used loop diuretic. Following an IV bolus, the diuretic effect peaks within 30 min. It produces relief of dyspnoea (by reduction in pre-load) sooner than would be expected from the diuresis. The diuretic effect is dose related. In patients with impaired renal function larger doses may be necessary.

Uses
Acute oliguric renal failure – may convert acute oliguric to nonoliguric renal failure. Other measures must be taken to ensure adequate
circulating blood volume and renal perfusion pressure
Pulmonary oedema – secondary to acute left ventricular failure
Oedema – associated with congestive cardiac failure, hepatic failure and renal disease

Contraindications
Oliguria secondary to hypovolaemia

Administration
• IV bolus: 10–40 mg over 3–5 min
• IV infusion: 2–10 mg/h
For high-dose parenteral therapy (up to 1000 mg/day), dilute in 250–500 ml sodium chloride 0.9% given at a rate not >240 mg/h

How not to use furosemide
Glucose-containing fluid is not recommended as a diluent (infusion pH _5.5, otherwise may precipitate)
Do not give at >240 mg/h (transient deafness)

Adverse effects
Hyponatraemia, hypokalaemia, hypomagnesaemia
Hyperuricaemia, hyperglycaemia
Ototoxicity
Nephrotoxicity
Pancreatitis

Cautions
Amphotericin (increased risk of hypokalaemia)
Aminoglycosides (increased nephrotoxicity and ototoxicity)
Digoxin toxicity (due to hypokalaemia)

Organ failure
Renal: may need to increase dose for effect

Renal replacement therapy
No further dose modification is required during renal replacement therapy