A Study of Safety and Efficacy in MK-0954A Combination in Participants With Hypertension (MK-0954A-373 AM3)

An Open-label, Single Arm, Prospective Study to Evaluate the Safety and Anti-hypertensive Efficacy of Losartan 50 mg / Hydrochlorothiazide (HCTZ) 12.5 mg Combination in Patients With Mild to Moderate Essential Hypertension

This study is being conducted to evaluate the safety and antihypertensive efficacy of MK-0954A (Losartan 50 mg / Hydrochlorothiazide (HCTZ) 12.5 mg) in participants with mild to moderate essential hypertension.

Inclusion criteria:

• Participant will have reached the legal age by the time of entrance into the run-in period.
• Participant has no active medical problem, other than essential hypertension,

which might of itself or by this treatment significantly affect the Participant's blood pressure.

- Participants diagnosed with mild to moderate essential hypertension or

hypertension accompanying with established cardiovascular (CV) and renal diseases who are receiving antihypertensive regimen (exclude diuretic), yet not attaining to treatment goal*.

* Note: For essential hypertension, the goal is to reduce the blood pressure to less than 140/90. For hypertension with established CV and renal diseases, the BP goal is < 130/80. (According to 2007 European Society of Hypertension (ESH) - European Society of Cardiology (ESC) guideline)

• Participant is either receiving antihypertensive therapy or no treatment.
• Participants with stable diabetes mellitus may enter the study.

Exclusion criteria:

• Pregnant or lactating females.
• Secondary hypertension of any etiology (such as unilateral or bilateral renal

disease, renal artery stenosis, coarctation of the aorta, pheochromocytoma).

• History of malignant hypertension.
• Sitting systolic blood pressure >210 mmHg at Visit 1 (Day 0).
• Participants with unresolved cerebrovascular accident or transient ischemic attack in the acute stage at visit 1.
• A clinically confirmed myocardial infarction within the recent 3 months.
• Angina pectoris.
• Clinically important cardiac arrhythmia.
• History of unexplained syncope within the prior 2 years, or a known syncopal

disorder.

- Presence of hemodynamically significant obstructive valvular disease of

cardiomyopathy.

• Percutaneous coronary angioplasty or coronary artery bypass surgery within the prior 3 months of visit 1.
• Participant with a single functioning kidney.