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The effect of low-dose hydrochlorothiazide on blood pressure, serum potassium, and lipoproteins
Insights
Low-dose hydrochlorothiazide (HCTZ) effectively lowers blood pressure in hypertensive women without causing low serum potassium. However, even low doses of HCTZ can negatively impact cholesterol and lipoprotein levels.
Area of Science:
- Cardiology
- Pharmacology
- Endocrinology
Background:
- Thiazide diuretics are commonly prescribed for hypertension.
- Concerns exist regarding potential adverse effects of thiazides on cardiovascular health, including impacts on serum lipids and electrolytes.
- Lowering diuretic dosage is a strategy to mitigate these risks.
Purpose of the Study:
- To evaluate the effects of two different daily doses of hydrochlorothiazide (HCTZ) on blood pressure, serum potassium, and serum lipoproteins in postmenopausal black hypertensive women.
- To compare the efficacy and safety of low-dose (12.5 mg) versus high-dose (112.5 mg) HCTZ.
Main Methods:
- A double-blind, randomized, crossover study design was employed.
- Nine postmenopausal black women with hypertension received daily doses of 12.5 mg and 112.5 mg of HCTZ for one month each.
- Measurements included sitting diastolic blood pressure, serum potassium, total cholesterol, LDL cholesterol, HDL cholesterol, apolipoprotein A1, apolipoprotein B, and the cholesterol:HDL ratio.
Main Results:
- Both 12.5 mg and 112.5 mg daily doses of HCTZ significantly reduced sitting diastolic blood pressure (8 mm Hg and 11 mm Hg, respectively).
- The high dose of HCTZ significantly reduced serum potassium (0.7 mEq/L), while the low dose did not.
- Both doses similarly affected serum lipoproteins, causing significant increases in total cholesterol, LDL cholesterol, and apolipoprotein B, and a significant decrease in apolipoprotein A1.
Conclusions:
- Low-dose HCTZ (12.5 mg) is effective in managing mild hypertension and avoids hypokalemia in postmenopausal black women.
- Despite the benefits for blood pressure and potassium levels, low-dose HCTZ is associated with adverse changes in serum lipids and lipoproteins.
- These findings suggest a need for careful monitoring of lipid profiles in patients treated with HCTZ, even at lower doses.
Abstract:
Recent clinical trials in hypertension suggest that thiazide diuretics may increase coronary heart deaths in selected patients, possibly through adverse effects on serum potassium, lipids, lipoproteins, and/or apolipoproteins. Administration of smaller doses of diuretics has been recommended to decrease this risk. We evaluated 12.5-mg and 112.5-mg daily doses of hydrochlorothiazide (HCTZ) administered for 1 month to nine postmenopausal black female hypertensives using a double-blind, randomized, crossover design. Both regimens produced significant reductions in sitting diastolic blood pressure, a mean of 11 mm Hg with the high dose and 8 mm Hg with the low dose. The high dose produced a mean 0.7 mEq/L reduction in serum potassium while the low dose caused no change. Both doses produced similar changes in serum lipoproteins. Statistically significant elevations were seen in total cholesterol (approximately 12%), LDL cholesterol (approximately 20%), cholesterol: HDL ratio (approximately 15%), and apolipoprotein B (approximately 20%). Apolipoprotein A1 was significantly reduced (approximately 6%). These results support the use of low doses of HCTZ in mild hypertension to avoid hypokalemia, but suggest that adverse changes in serum lipids will occur.