Hydrochlorothiazide (HCTZ)

Indications


Pharmacology

  • Sulfonamide Diuretic (see Sulfonamides, [[Sulfonamides]])
    • Site of Activity: distal tubule

Metabolism

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Administration

  • PO:

Dose Adjustment

  • Hepatic
  • Renal

Adverse Effects

Gastrointestinal Adverse Effects

Acute Pancreatitis (see Acute Pancreatitis, [[Acute Pancreatitis]])

  • Epidemiology: definite association with acute pancreatitis

Pulmonary Adverse Effects

Diffuse Alveolar-Interstitial Infiltrates/Acute Lung Injury-ARDS (see Pneumonia, [[Pneumonia]], Interstitial Lung Disease-Etiology, [[Interstitial Lung Disease-Etiology]], Acute Lung Injury-ARDS, [[Acute Lung Injury-ARDS]])

  • Epidemiology
    • Over 40 reported cases of diffuse infiltrates associated with hydrochlorothiazide
    • May begin with first dose of hydrochlorothiazide or may occur days later
    • 90% of cases occur in women who take hydrochlorothiazide intermttently (presumably for fluid retention), rather than daily
  • Diagnosis
    • Swan: normal PCWP
    • Absence of ANA and eosinophilia
    • CXR/Chest CT: diffuse alveolar-interstitial infiltrates
  • Clinical
    • Dyspnea (see Dyspnea, [[Dyspnea]]): fairly rapid onset
    • Fever (see Fever, [[Fever]]): may occur
  • Treatment: withdraw hydrochlorothiazide -> usually clears within 48-72 hrs

Drug-Induced Pulmonary Eosinophilia (see Drug-Induced Pulmonary Eosinophilia, [[Drug-Induced Pulmonary Eosinophilia]])

  • Epidemiology:

Renal Adverse Effects

Acute Interstitial Nephritis (see Acute Interstitial Nephritis, [[Acute Interstitial Nephritis]])

  • Physiology: class effect common to all thiazides

Hyponatremia (see Hyponatremia, [[Hyponatremia]])

  • Thiazide diuretics act at the distal tubule
  • Mechanisms postulated for thiazide diuretic-induced hyponatremia include hypovolemia-stimulated ADH and interference with urinary dilution in the cortical diluting segment
  • Some studies have identified specific risk factors for the development of hyponatremia and these include: institutionalized elderly patients, low serum potassium concentration, low total body weight and indapamide use

Other Adverse Effects

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References

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