Thiazide diuretics in hypertension.

Thiazide diuretics have antihypertensive efficacy equivalent to that of the other major classes of antihypertensive drug, and are at least as well tolerated as judged by discontinuation rates and measures of quality of life. They are effective when given once daily, require no dose titration, have few contraindications, and have additive effects when combined with drugs of other classes. The dose-response relation for blood pressure is flat, whereas the subjective and biochemical side-effects are dose-dependent. They should be prescribed only at low dosage. Treatment regimens based on low-dose thiazide prevent stroke, coronary events, heart failure and renal failure in hypertension, and have proven safety. Thiazides are inexpensive. Low-dose thiazides should be preferred for routine first-line treatment of hypertension unless they are contraindicated or there is a compelling indication for an alternative class of drug.