Pharm

Acetazolamide

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Acetazolamide, Diamox, Systemic Carbonic Anhydrase Inhibitor

  • Mechanism
  1. Diuretic in the Carbonic Anhydrase Inhibitor Class
  2. Decreases secretion of Aqueous Humor (Glaucoma)
  3. Decreases Hydrogen Ion at renal proximal tubule
    1. Prevents bicarbonate uptake resulting in urine alkalization
    2. Increased renal excretion of Sodium, Potassium, bicarbonate and water
    3. Results in hypokalemic Metabolic Acidosis and Respiratory Alkalosis (mechanism in High Altitude Illness)
      1. Lower resting PaCO2
      2. Higher resting Minute Ventilation
      3. Increased PaO2
  • Indications
  1. High Altitude Sickness treatment and prevention
  2. Pseudotumor Cerebri
  3. Open Angle Glaucoma
    1. Intraocular Carbonic Anhydrase Inhibitor
    2. Systemic Acetazolamide (IV or oral) may be used in acute exacerbation of chronic Open Angle Glaucoma
  • Dosing
  1. High Altitude Sickness
    1. Prevention
      1. Adults: 125 mg orally every 12 hours (FDA approved)
        1. Up to 250 mg twice daily may be used (but 125 mg is typically sufficient)
      2. Children: 2.5 mg/kg up to 125 mg every 12 hours (off-label)
      3. Start 24 hours before ascent
      4. Continue for 72 hours or until acclimitization to highest sleeping altitude
    2. Insomnia at altitude: 125 mg PO qhs
    3. Treatment: 250 mg orally twice daily (up to 400 mg twice daily has been used)
  2. Pseudotumor Cerebri
    1. Dose range: 125-250 mg PO qd-tid
  3. Open Angle Glaucoma acute exacerbation
    1. Dose: 250 mg orally or IV every 4-6 hours (maximum 1 gram/day)
  • Adverse Effects
  • Drug Interactions
  • References
  1. Olson (2020) Clinical Pharmacology, Medmaster, Miami, p. 62-3
  2. Hamilton (2010) Tarason Pocket Pharmacopeia, p. 224