Low doses of thiazide diuretics are effective in controlling isolated
systolic hypertension in most elderly patients. These agents are well
tolerated and do not appear to adversely affect quality of life. Bioch
emical adverse effects are minimal with low doses. Of greatest importa
nce, thiazide diuretics are the only class of antihypertensives that h
as been shown to reduce risk of cardiovascular events in patients with
isolated systolic hypertension. Recent studies showed all these advan
tages with both chlorthalidone and hydrochlorothiazide therapy, althou
gh low-dose hydrochlorothiazide may cause less hypokalemia in the elde
rly than does chlorthalidone.