Loop diuretics cause less postural hypotension than thiazide diuretics in the frail elderly

Area of Science:

• Gerontology
• Pharmacology
• Cardiology

Background:

• Frail elderly patients are susceptible to adverse effects from medications.
• Diuretics are commonly prescribed for mild cardiac failure in older adults.
• The safety profiles of loop and thiazide diuretics in this population require investigation.

Purpose of the Study:

• To compare the incidence of postural hypotension in frail elderly patients treated with thiazide diuretics versus loop diuretics (frusemide).
• To assess the relationship between plasma potassium levels and postural hypotension in patients on these diuretics.

Main Methods:

• A comparative study involving 70 frail elderly patients attending a day hospital.
• Patients were divided into three groups: no diuretic (control, n=30), loop diuretic (frusemide, n=20), and thiazide diuretic (n=20).
• Postural hypotension was defined as a systolic blood pressure reduction >20 mmHg upon standing; plasma potassium levels were measured.

Main Results:

• Patients on thiazide diuretics exhibited a significantly higher incidence of postural hypotension (12/20) compared to those on loop diuretics (4/20).
• Mean plasma potassium levels were lower in the thiazide group than in the frusemide group.
• Lower potassium levels significantly correlated with a greater drop in systolic blood pressure from supine to standing.

Conclusions:

• Loop diuretics (frusemide) appear to be as safe or safer than thiazide diuretics in frail elderly patients.
• The established reputation of thiazides as safer first-line drugs for cardiac failure in the elderly may be unjustified.
• Clinical practice should reconsider the first-line choice of diuretics in this vulnerable patient group.