Blood pressure medications have very different mechanisms of action. They work in different ways. Some medications used in the treatment of hypertension contain a diuretic. Others do not. Your primary care physician is best suited to decide which hypertensive medication is right for you.
The regulation of blood pressure is multi-faceted. Some patients have fluid overload that is a contributing factor to the hypertension. These patients may be prescribed a medication that contains a diuretic. Diuretics decrease CV fluid levels and thus lower the blood pressure. When someone takes a diuretic urine output is increased and sometimes a drastic increase is noted and the dosage of the medication may need to be lowered.