The antihypertensive efficacy of HCTZ in its daily dose of 12.5 to 25 mg as measured in head-to-head studies by ambulatory BP measurement is consistently inferior to that of all other drug classes .
Because outcome data at this dose are lacking , HCTZ is an inappropriate first-line drug for the treatment of hypertension
OBJECTIVES The purpose of this study was to evaluate the antihypertensive efficacy of hydrochlorothiazide ( HCTZ ) by ambulatory blood pressure ( BP ) monitoring .
BACKGROUND HCTZ is the most commonly prescribed antihypertensive drug worldwide .
More than 97 % of all HCTZ prescriptions are for 12.5 to 25 mg per day .
The antihypertensive efficacy of HCTZ by ambulatory BP monitoring is less well defined .
Comparative Antihypertensive Effects of Hydrochlorothiazide and Chlorthalidone on Ambulatory and Office Blood Pressure
Low-dose thiazide-type diuretics are recommended as initial therapy for most hypertensive patients .  Chlorthalidone has significantly reduced stroke and cardiovascular end points in several l and mark trials ; however , hydrochlorothiazide remains favored in practice . Most clinicians assume that the drugs are interchangeable , but their antihypertensive effects at lower doses have not been directly compared . We conducted a r and omized , single-blinded , 8-week active treatment , crossover study comparing chlorthalidone 12.5 mg/day ( force-titrated to 25 mg/day ) and hydrochlorothiazide 25 mg/day ( force-titrated to 50 mg/day ) in untreated hypertensive patients . The main outcome , 24-hour ambulatory blood pressure ( BP ) monitoring , was assessed at baseline and week 8 , along with st and ard office BP readings every 2 weeks . Thirty patients completed the first active treatment period , whereas 24 patients completed both . An order – drug – time interaction was observed with chlorthalidone ; therefore , data from only the first active treatment period was considered . Week 8 ambulatory BPs indicated a greater reduction from baseline in systolic BP  with chlorthalidone 25 mg/day compared with hydrochlorothiazide 50 mg/day ( 24-hour mean = −12.4±1.8 mm Hg versus −7.4±1.7 mm Hg ; P=0.054 ; nighttime mean = −13.5±1.9 mm Hg versus −6.4±1.8 mm Hg ; P=0.009 ) . Office systolic BP reduction was lower at week 2 for chlorthalidone 12.5 mg/day versus hydrochlorothiazide 25 mg/day ( −15.7±2.2 mm Hg versus −4.5±2.1 mm Hg ; P=0.001 ) ; however , by week 8 , reductions were statistically similar ( −17.1±3.7 versus −10.8±3.5 ; P=0.84 ) . Within recommended doses , chlorthalidone is more effective in lowering systolic BPs  than hydrochlorothiazide , as evidence d by 24-hour ambulatory BPs . These differences were not apparent with office BP measurements
The antihypertensive efficacy of HCTZ in its daily dose of 12.5 to 25 mg as measured in head-to-head studies by ambulatory BP measurement is consistently inferior to that of all other drug classes .
Because outcome data at this dose are lacking , HCTZ is an inappropriate first-line drug for the treatment of hypertension
OBJECTIVES The purpose of this study was to evaluate the antihypertensive efficacy of hydrochlorothiazide ( HCTZ ) by ambulatory blood pressure ( BP ) monitoring .
BACKGROUND HCTZ is the most commonly prescribed antihypertensive drug worldwide .
More than 97 % of all HCTZ prescriptions are for 12.5 to 25 mg per day .
The antihypertensive efficacy of HCTZ by ambulatory BP monitoring is less well defined .