Hydrochlorothiazide is a thiazide diuretic (water pill) that helps prevent your body from
absorbing too much salt, which can cause fluid retention.
Olmesartan is in a group of drugs called angiotensin II receptor antagonists. Olmesartan keeps
blood vessels from narrowing, which lowers blood pressure and improves blood flow.
The combination of olmesartan and hydrochlorothiazide is used to treat high blood pressure
(hypertension).
Olmesartan and hydrochlorothiazide may also be used for other purposes not listed in this
medication guide.