Loop Diuretics (Old)

Summary

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Key Points

• Key Drugs
  • Furosemide
  • Bumetanide
  • Torsemide
  • Ethacrynic acid
  • Mechanism (Saunders, Wolters Kluwer)
    • Causes diuresis by inhibiting sodium-potassium-chloride triple transporter at the ascending loop of Henle (hence the name… Loop Diuretics)
    • Loop diuretics are the most powerful diuretics and are rapid-acting. Onset of drug IV is 5 minutes
    • Work even in cases of severe renal impairment (unlike thiazides and potassium-sparing diuretics)
  • Clinical Use (Saunders, Mictlan)
    • Remove Excess Fluid (Diuresis)
      • Pulmonary edema caused by Heart Failure
      • Peripheral edema
      • Hypertension
      • Ascites associated with liver failure (cirrhosis)
      • Nephrotic syndrome
      • Will lead to increased urination
        • Avoid administering late in the day to prevent nocturia and risk of falling. Provide easy access to the bathroom if a catheter is not present.
        • Report urine output less than 30 mL/hour
  • Side Effects and Adverse Reactions (Saunders)
    • Electrolyte imbalances
      • Hypokalemia (potassium-wasting)
        • Can lead to muscle cramps, weakness, and life-threatening heart arrhythmias
        • Closely monitor potassium levels
        • Supplement with potassium, educate patient to eat foods high in potassium, do not administer if patient has low potassium (below 3.5)
      • Hyponatremia
      • Hypocalcemia
      • Hypomagnesemia
    • Ototoxicity
      • Furosemide only
      • Caused by too rapid of administration
        • Do not give faster than 4 mg/min IV
    • Dehydration
      • Daily weights are the best indicator of fluid retention/fluid loss.
        • Encourage patients on furosemide, especially those with heart failure, to measure weight daily and contact their doctor with extreme weight gain or weight loss.
      • Closely monitor intake and output in the hospital setting.
      • Patients should monitor how much liquid they intake and follow provider’s instruction
        • Too much fluid intake counters the effect of the diuretic, too little liquid can cause dehydration
    • Hypotension
      • Due to sudden drop in fluid volume
      • Closely monitor blood pressure
      • Encourage patient to change positions slowly to minimize dizziness associated with orthostatic hypotension
    • Hyperuricemia
      • Use with caution in patients experiencing gout