For whom are thiazide (thiazide diuretics) not recommended?

Contraindications for Thiazide Diuretics

Thiazide diuretics are not recommended for patients with severe renal impairment (eGFR <30 mL/min/1.73m²), a history of gout, or those with multiple metabolic risk factors increasing the risk of new-onset diabetes. 1, 2

Renal Function Contraindications

Thiazide diuretics lose their effectiveness in patients with impaired renal function, particularly when:

• GFR falls below 30 mL/min/1.73m² 1
• Severe chronic kidney disease is present 2

In these patients:

• Loop diuretics are preferred as they maintain efficacy at lower GFR levels 2
• Thiazides may be used synergistically with loop diuretics in severe heart failure despite renal impairment, but not as monotherapy 1

Metabolic Contraindications

Thiazides should be avoided in:

1. Patients with a history of gout 1

   • Use with caution unless the patient is on uric acid-lowering therapy
   • Thiazides can precipitate hyperuricemia and acute gout attacks 3

2. Patients with multiple metabolic risk factors 1

   • Beta-blockers and thiazide diuretics are not recommended in hypertensive patients with multiple metabolic risk factors due to increased risk of new-onset diabetes
   • This recommendation has a Class III, Level A evidence rating (strong evidence against use) 1

3. Patients with diabetes requiring careful glucose control 3, 4

   • Thiazides can worsen glycemic control in patients with existing diabetes
   • They may require adjustment of antidiabetic medication dosages 3

Other Contraindications

Thiazides should be used with caution or avoided in:

• Patients with electrolyte disturbances 3

  • Risk of hypokalemia, hyponatremia, hypochloremic alkalosis
  • Risk of hypomagnesemia

• Patients with impaired hepatic function 3

  • Can precipitate hepatic coma in severe liver disease

• Patients with parathyroid disease 3

  • Calcium excretion is decreased by thiazides
  • Pathologic changes in parathyroid glands with hypercalcemia have been observed

• Patients with angle-closure glaucoma risk 3

  • Can cause idiosyncratic reaction leading to acute angle-closure glaucoma
  • Risk factors include history of sulfonamide or penicillin allergy

Special Considerations

• Elderly patients require careful dosing and monitoring due to:

  • Greater blood pressure reduction effects
  • Increased side effect risk 3
  • Starting with lowest available dose (12.5 mg) is recommended

• Pregnant women:

  • Thiazides cross the placental barrier
  • Risk of fetal/neonatal jaundice and thrombocytopenia 3

• Nursing mothers:

  • Thiazides are excreted in breast milk
  • Potential for serious adverse reactions in nursing infants 3

Monitoring Recommendations

For patients on thiazide therapy who don't have contraindications, careful monitoring is essential:

• Regular assessment of electrolytes (potassium, sodium, chloride)
• Blood glucose monitoring, especially in those at risk for diabetes
• Serum uric acid levels, particularly in those with gout risk factors
• Renal function tests

When thiazides are absolutely necessary despite relative contraindications, using the lowest effective dose and close monitoring can help mitigate risks 3.