frusemide / furosemide / Lasix

see also:

• diuretics

• a potent potassium losing loop diuretic mainly used in the Rx of congestive cardiac failure
• inhibits sodium and chloride absorption in the ascending limb of Henle's loop and in both the proximal and distal tubules

• rapidly absorbed from GIT:
  • 60-69% in normal adults
  • < 50% in end stage renal failure (ESRF)
  • onset of diuresis following oral administration is within 1 hour
  • peak effect occurs within the first or second hour
  • duration of diuretic effect is 6 to 8 hours
• in intravenous usage:
  • onset of diuresis following oral administration is within 5 minutes
  • peak effect occurs within the first hour
  • duration of diuretic effect is ~2 hours

• known hypersensitivity to frusemide or sulphonamides or any of the inactive ingredients
• complete renal shut down / anuria
• increasing oliguria and azotaemia during progressive renal failure
• severe hypokalaemia, hyponatraemia, hypovolaemia, dehydration or hypotension
• hepatic encephalopathy
• lactation
• pregnancy
• icteric neonates
• do not inject 250mg frusemide iv as a bolus

• elderly patients and others at risk of dehydration, collapse and deep venous thrombosis (DVT)
• digoxin Rx as risk of hypokalaemia leasing to toxicity
• cirrhosis as sudden changes in fluid balance may precipitate hepatic encephalopathy
• risk of ototoxicity, especially if either:
  • rapid injection or infusion (maximum injection rate of 4 mg/minute)
  • severe renal impairment
  • hypoproteinaemia / nephrotic syndrome
  • doses exceeding several times the usual recommended dose
  • concomitant therapy with aminoglycoside antibiotics, ethacrynic acid or other ototoxic drugs
• neuro-muscular blockers
• risperidone - combined use in the elderly with dementia appeared to double mortality!
• avoid strict restriction of sodium intake
• impairment of micturition (e.g. prostatic hypertrophy) as risk of acute retention
• gout, may precipitate gout
• monitor for electrolyte disturbances such as hypokalaemia, hyponatraemia and hypochloraemic alkalosis
• may lower calcium levels
• increases cholesterol and triglycerides short-term
• may exacerbate or, rarely, activate systemic lupus erythematosus (SLE)

• usual starting dose is 20-40mg mane or 2mg/kg in children
• may increase to 2nd dose at midday
• may be carefully titrated up to 400 mg/day (except in advanced renal failure) in those patients with severe clinical oedematous states
• patients with acute pulmonary oedema (APO) are often given 40mg slow iv stat dose and if no response within 1 hr, a 2nd 80mg slow iv dose given