The majority of hypertensive patients require antihypertensive associations to control their blood pressure. Most of clinical trials don't compare different associations using Hydrochlorothiazide 25 mg as the standard initial therapy and compare the associations using doses that are not equivalent.

This randomized trial where patients and investigators are blinded and compares the effectiveness two associations: Hydrochlorothiazide and Amiloride and Hydrochlorothiazide and Enalapril.

Inclusion Criteria:

• patients who are using Hydrochlorothiazide 25mg/d at least in a four weeks treatment and had their office blood pressure not controlled (systolic or diastolic greater than 140 mmHg or 90 mmHg, respectively).

Exclusion Criteria:

• Established cardiovascular disease
• Diabetics in use of insulin
• Impairment renal in renal function
• Contraindications for the study medications