Hello Laura Caston,

Both medications can help you lower you blood pressure. 

Dyazide is a combination of triamterene and hydrochlorothiazide, both of which are diuretics; these drugs lower your blood pressure by decreasing the amount of water in your blood vessels. 

Benicar works in a completely different way.  Benicar, of the ARB (aka angiotensen receptor blocker class), works by blocking the action of a hormone in the body that both dilates the blood vessels and increases the amount of water in the blood.

Both drugs are safe, well-tolerated, and effective in reducing pressure; depending on your health insurance, cost may end up being the most important factor in deciding which medication you take. 

To your health,

Neil MD