To evaluate the efficacy on blood pressure reduction, safety and tolerability of two different dosages of canrenone as add-on therapy in patients already treated with Angiotensin Converting-Enzyme Inhibitors (ACE-I) or Angiotensin II Receptor Blockers (ARBs) and diuretics at the maximum dosage.

To evaluate the efficacy on blood pressure reduction, safety and tolerability of two different dosages of canrenone as add-on therapy in patients already treated with Angiotensin Converting-Enzyme Inhibitors (ACE-I) or Angiotensin II Receptor Blockers (ARBs) and diuretics at the maximum dosage.

In this multi-centre, phase IV, randomized, controlled, open-label, parallel groups trial, 180 Caucasian patients affected by uncomplicated, essential hypertension, not well controlled by concomitant administration of ACE-I or ARBs and diuretics at the maximum dosage will be enrolled.

At baseline patients will be randomized to canrenone, 50 mg, or canrenone 100 mg once a day, in addition to their current therapy, for three months.

At the baseline, and after 3 months will be evaluated: systolic (SBP) and diastolic blood pressure (DBP), pulse pressure (PP), heart rate, fasting plasma glucose (FPG), homeostasis model assessment insulin (HOMA-index), total cholesterol, HDL-cholesterol, triglycerides, LDL-cholesterol, sodium, potassium, calcium, magnesium, uric acid, estimated glomerular filtration rate (eGFR), plasmatic urea, brain natriuretic peptide (BNP), aldosterone, and galectin-3.

Inclusion Criteria:

• Caucasian patients affected by uncomplicated, essential hypertension, not well controlled by concomitant administration of ACE-I or ARBs and diuretics at the maximum dosage.

Exclusion Criteria:

• diabetes mellitus
• secondary hypertension
• pregnancy