Furosemide (Lasix)

Category:

  • Diuretic

Description:

  • Loop diuretic

Indications:

  • Edema associated with CHF, hepatic cirrhosis, renal disease, nephrotic syndrome

  • Hypertension

  • Pulmonary edema

Contraindications:

  • Anuria

Precautions:

  • Pregnancy category C; excreted into breast milk

  • Diabetes mellitus, dehydration, severe renal disease, cirrhosis ascites

  • System lupus erythematosis

  • Gout

  • Take with food or milk to reduce GI upset; avoid prolonged exposure to sunlight

Adverse Reactions (Side Effects):

  • CNS: dizziness, fever, headache, paresthesia, restlessness, vertigo

  • CV: chest pain, cardiovascular collapse, ECG changes, orthostatic hypotension

  • EENT: blurred vision, ototoxicity

  • GI: anorexia, constipation, cramping, diarrhea, ischemic hepatitis, jaundice, nausea, vomiting, oral and gastric irritation

  • GU: glycosuria, hyperuricemia, urinary bladder spasm

  • HEME: agranulocytosis, anemia, aplastic anemia, leukopenia, purpura, thrombocytopenia

  • METAB: hyperglycemia

  • SKIN: erythema multiforme, exfoliative dermatitis, interstitial nephritis, necrotizing angiitis, photosensitivity, pruritis, rash urticaria  

Dosage:

Administered orally (tablets, solution), intravenously, and intramuscularly

  • Adult: 

    • PO 20-80 mg daily in the morning; may give another dose in 6 hours; increase in increments of 20-40mg up to 400mg daily if response not satisfactory: 

    • IM/IV 20-40mg, increased by 20mg every 2 hours until desired response (rule of thumb: IV dose = oral dose).

    • Pulmonary edema: 

      • IV 40mg given over several minutes, repeated in 1 hour; increase to 80mg if needed

  • Child: 

    • PO/IM/IV 1-2 mg/kg/dose up to 6 mg/kg/day in divided doses every 6-12 hours

Drug Interactions:

  • Additive/increased ototoxicity: aminoglycosides

  • Enhanced nephrotoxicity: cephalosporins

  • Diuretic induced hypokalemia may increase risk of digitalis toxicity: digoxin, digitoxin

  • Reduced diuretic response: barbiturates, phenytoin

  • Case reports of sudden death hyponatremia proposed; causal relationships not established: seratonin-reuptake inhibitors

  •  Additive hypokalemia: terbutaline

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