Intervention: Chlorthalidone
Trial phase: Phase 3
ATC code: C03BA04 | C03BB04 | C03EA06 | G01AE10
SMILES: NS(=O)(=O)c1cc(C2(O)NC(=O)c3ccccc32)ccc1Cl
Sex: All
Age groups: Adult | Older Adult
Healthy volunteers: No
Participants at risk: 181
Group description: Chlorthalidone 25 mg, tablets, orally, once daily for up to 6 weeks.
Eligibility criteria:
Inclusion Criteria

Has essential hypertension (defined as sitting trough clinic systolic blood pressure between 160 and 190 mm Hg inclusive at Day minus 1 and 24-hour mean systolic blood pressure greater than or equal to 140 mm Hg and ≤ 180 mm Hg at Day 1).
Females of childbearing potential who are sexually active must agree to use adequate contraception, and can neither be pregnant nor lactating from Screening throughout the duration of the study.
Has clinical laboratory evaluations (including clinical chemistry, hematology, and complete urinalysis) within the reference range for the testing laboratory or results that are deemed not clinically significant for inclusion into this study by the investigator.
Willing to discontinue current antihypertensive medications at the Screening Day minus 21 visit. If the subject is on amlodipine prior to screening, the subject is willing to discontinue this medication at Screening Day minus 28.

Exclusion Criteria

Has sitting trough clinic diastolic blood pressure greater than 119 mmHg at Day minus 1.
Has a baseline 24 hour ambulatory blood pressure monitor reading of insufficient quality.
Is required to take or continues taking any disallowed medication, prescription medication, herbal treatment or over-the counter medication that may interfere with evaluation of the study medication.
Recent history (within the last 6 months) of myocardial infarction, heart failure, unstable angina, coronary artery bypass graft, percutaneous coronary intervention, hypertensive encephalopathy, cerebrovascular accident, or transient ischemic attack.
Clinically significant cardiac conduction defects (for example, 3rd degree atrioventricular block, left bundle branch block, sick sinus syndrome, atrial fibrillation).
Hemodynamically significant left ventricular outflow obstruction due to aortic valvular disease.
The subject has secondary hypertension of any etiology.
Non-compliant (less than 70% or greater than 130%) with study medication
during the placebo run- in period.
Severe renal dysfunction or disease (based on calculated creatinine clearance less than 30 mL/min/1.73 m2) at Screening.
Known or suspected unilateral or bilateral renal artery stenosis.
History of drug abuse (defined as illicit drug use) or a history of alcohol abuse (defined as regular or daily consumption of more than 2 alcoholic drinks per day) within the past 2 years.
Previous history of cancer that has not been in remission for at least 5 years prior to the first dose of study drug. (This criterion does not apply to those subjects with basal cell or Stage 1 squamous cell carcinoma of the skin.)
Type 1 or poorly controlled type 2 diabetes mellitus (glycosylated hemoglobin greater than 8.0%).
Hypo- or hyperkalemia (defined as serum potassium outside of the normal reference range of the central laboratory).
Alanine aminotransferase level of greater than 2.5 times the upper limit of normal, active liver disease, or jaundice.
Upper arm circumference less than 24 cm or greater than 42 cm.
Works night (3rd) shift (defined as 11PM [2300] to 7AM [0700]).
Currently is participating in another investigational study or has participated in an investigational study within 30 days prior to randomization.
Study site employee, or is an immediate family member ( ie, spouse, parent, child, sibling) of a study site employee who is involved in conduct of this study.
Any other serious disease or condition at Screening (or Randomization) that would compromise subject safety, might affect life expectancy, or make it difficult to successfully manage and follow the subject according to the protocol.
Randomized in a previous azilsartan medoxomil study.