- Period 1 from week-4 to week 0 : 4-week treatment for all patients with irbesartan 300 mg, HCTZ 12.5mg, amlodipine 5 mg. At the end of this period, an ABPM will be performed: only patients with a mean day time SBP>135 and/or DBP>85 mmHg will be randomized for a further 3 months treatment