Brand Name : LASIREX
Generic Name : Frusemide
Preparation : 40 mg Tablet
Pharmacological Category : Loop Diuretic

Mechanism of Action (MOA)
LASIREX (Frusemide) blocks chloride binding site on the sodium-potassium-chloride cotransporter (Na+K+2Cl) in the thick ascending limb of the loop of Henle. Thus, excretion of sodium, potassium, chloride ions is increased and water excretion is enhanced.


  • Absorption : From the gastrointestinal tract
  • Onset of Action : Diuresis: 30 minutes to 1 hour
  • Peak Effect : 1 to 2 hours
  • Duration of Action : 6 to 8 hours
  • Bioavailability : 47 to 64%
  • Protein Binding : 91 to 99%
  • Metabolism : Liver (nearly 10%)
  • Elimination Half-life : Normal renal function : 0.5 to 2 hours; End Stage Renal Disease : 9 hours
  • Excretion : Urine (50%)

Indications and Dosage

  • Edema associated with Congestive Heart Failure, Liver Cirrhosis and Renal Disease (Nephrotic Syndrome) : LASIREX 20 to 80 mg as a single dose. May repeat the same dose if needed or increase by LASIREX 20 mg no sooner than 6 to 8 hours after the previous dose until desired diuretic effect has been obtained; give individually determined single dose once or twice daily
  • Severe Edematous States : May carefully titrate dose up to LASIREX 600 mg per day
  • Hypertension : One tablet of LASIREX twice daily. Adjust dose according to the response.

Side Effects
Most adverse effects occur with high doses, and serious side effects are uncommon.
COMMON : Hyponatremia, hypokalemia, and hypochloraemic alkalosis after large doses or prolonged use.
Signs of electrolyte imbalance include headache, hypotension, muscle cramps, dry mouth, thirst, weakness, lethargy, drowsiness, restlessness, oliguria, cardiac arrhythmias, and gastrointestinal disturbances
SEEN : Hypovolemia and dehydration especially in the elders, hyperuricemia and precipitate gout in some patients
RARE : Blurred vision, yellow vision, dizziness, orthostatic hypotension

Hypersensitivity to frusemide or sulfonamide, anuria

Warnings / Precautions

  • All diuretics produce changes in fluid and electrolyte balance so should be used cautiously especially in elderly.
  • Should be avoided in patients with severe hepatic impairment, in whom encephalopathy may be precipitated.
  • Patients with hepatic cirrhosis are also more likely to develop hypokalaemia.
  • All patients should be carefully observed for signs of fluid and electrolyte imbalance, especially in the presence of vomiting or during parenteral fluid therapy.
  • Diuretics should be given with caution in renal impairment since they can further reduce renal function likewise in patients with prostatic hyperplasia or impairment of micturition since it can precipitate acute urinary retention.
  • Should be used cautiously during pregnancy and breast feeding since it crosses the placenta and appears in breast milk.

Drug Interactions

  • Frusemide may enhance the nephrotoxicity of cephalosporin antibacterials.
  • Frusemide can enhance the ototoxicity of aminoglycoside antibacterials and ototoxic drugs.
  • Diuretic induced hypokalaemia may enchance the toxicity of digitalis glycosides and may also increase the risk of arrhythmias with drugs that prolong the QT interval such as astemizole, terfenadine, sotalol.
  • Frusemide enhance the effect of alpha blockers / ACE inhibitors.
  • Alcohol, barbiturates or opioids enhance orthostatic hypotension associated with frusemide.
  • Corticosteroids, NSAIDs or carbenoxolone antagonizes antihypertensive effects of frusemide.
  • Frusemide may enhance the nephrotoxicity of NSAIDs.

Pregnancy Category : C

LASIREX 40 mg : A box of 20 blisters, each blister of 10 tablets