Hydrochlorothiazide is HCTZ....(generic name). It's the mainstay of diuretic hypertension treatment. A lot of people take it alone. But since thiazide diuretics tends to rob the body of potassium, triamterene (another diuretic) is added in small quantity which has potassium-sparing qualities and in theory helps offset any potassium depletion that may happen on HCTZ alone. Maxide and Dyazide are the Brand names for a combo pill of hydrochlorthiazide (HCTZ) with triamterene. Chemically there is no difference bewteen brand name and generic. No other differences except to your wallet $$$!