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 = ½ 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