Telmisartan With or Without Hydrochlorothiazide (HCTZ) Compared With Losartan With or Without HCTZ in Mild to Moderate Hypertensive Patients

Study to assess the efficacy of telmisartan 40-80 mg once daily compared with losartan 50-100 mg once daily in hypertensive patients evaluated by change from baseline in diastolic blood pressure (DBP) during the last 6 hours of the 24-hour dosing interval, at the end of the 12 weeks period of monotherapy treatment (ABPM - ambulatory blood pressure measurement).

Secondary objectives: Changes from baseline in BP at the end of the monotherapy period of treatment and at the end of the study, evaluated by sphygmomanometric blood pressure measurement and ABPM

Safety:

Incidence of adverse events (AE's); withdrawal due to adverse events; laboratory parameters


Eligibility Criteria:
Inclusion Criteria:

* Age ≥ 18 years
* Mild-to-moderate essential hypertension defined as a mean diastolic blood pressure (DBP) ≥ 95 mmHg and \< 110 mmHg and systolic blood pressure (SBP) \< 180 mmHg measured by manual cuff sphygmomanometer at the end of the wash-out period
* Written informed consent

Exclusion Criteria:

* Nursing, pregnancy or childbearing potential women, post-menopausal women will be enrolled with last menstruation \> 1 year prior to start wash-out phase or surgically sterile
* Secondary hypertension
* Malignant hypertension (retinal haemorrhage, exudates or papillary oedema)
* Clinically significant sodium depletion as defined by serum sodium level \< 130 mEq/L and/or clinically significant hyperkaliemia as defined by serum potassium level \> 5.5 mEq/L or clinically significant hypokaliemia as defined by serum potassium level \< 3.0 mEq/L
* Atrial fibrillation or frequent ventricular ectopic beats or other arrhythmias which, in the investigator opinion could compromise patient's participation to the trial
* Congestive heart failure (CHF) (NYHA (New York Heart Association) functional class CHF III-IV)
* Angina pectoris or myocardial infarction
* Cardiac surgery within the past 3 months prior to start the wash-out period
* Stroke within the past 6 months prior to start the wash-out period
* Renal insufficiency defined as creatininaemia \> 2mg/dl
* Bilateral renal artery stenosis, renal artery stenosis in a solitary kidney, post renal transplant, presence of only one functioning kidney
* Liver insufficiency, defined as bilirubinaemia \> 2mg/dl and AST (aspartate aminotransferase) or ALT (alanine-aminotransferase) \> twice the upper normal range
* Clinically significant metabolic and endocrine disease
* Autoimmune disease
* Previous history of angioedema
* Body mass index \> 30kg/m2
* Arm circumference \> 32 cm
* Any condition that may be likely to compromise patients participation to the trial (alcohol or drug abuse, disability illness, etc.)
* Concomitant therapy with antihypertensive drugs non permitted by protocol, corticosteroids or drugs known to affect blood pressure
* Concomitant use of lithium or cholestyramine or colestipol resins (potential drug interactions with HCTZ)
* Investigational drug treatment within the past 30 days before the enrolment or concurrent participation to any other trial
* Sensitivity, significant adverse reaction or contraindications to the study drugs (telmisartan, losartan, HCTZ)
* Predictable lack of patient co-operation