Chlorthalidone Compared to Hydrochlorothiazide on Endothelial Function

The Effect of Chlorthalidone Compared to Hydrochlorothiazide on Endothelial Function in Hypertensive Patients: A Pilot Study

Chlorthalidone will result in improved endothelial function compared to hydrochlorothiazide as measured by flow mediated vasodilatation.

This is a randomized, double-blind, crossover study to evaluate chlorthalidone and hydrochlorothiazide and their effects on endothelial function in hypertensive patients. Subjects will receive chlorthalidone 12.5 mg, hydrochlorothiazide 25 mg, and placebo each for 4 weeks with a 1 week washout between study periods. Sequence of study drugs will be randomized. Flow mediated vasodilatation will be measured at baseline and after each treatment period.

Inclusion Criteria:

• Age 19 or older
• Diagnosis of hypertension
• Current blood pressure > 120/80 mm Hg

Exclusion Criteria:

• Use of a thiazide-type diuretic within the last 1 month
• Known allergy to any study medications
• History of gout or hyperuricemia
• SCr >/= 1.8 mg/dl or CrCl < 25 ml/min
• Pregnancy or breastfeeding or planning to become pregnant during study period
• Dementia or cognitive impairment
• Hypokalemia
• Acute coronary syndrome or stroke within 6 months
• Current use of sildenafil, tadalafil, or vardenafil