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: 372
Group description: Azilsartan medoxomil 20 mg and chlorthalidone 12.5 mg, tablets, orally, and olmesartan medoxomil-hydrochlorothiazide placebo tablets once daily for 8 weeks.

If participant does not achieve target blood pressure at Week 4, then the dosage will be increased to azilsartan medoxomil 40 mg and chlorthalidone 25 mg, tablets, orally, once daily for the remaining 4 weeks.
Eligibility criteria:
Inclusion Criteria:

190 mm Hg on Day -1 or if the participant has not received antihypertensive treatment within 28 days before screening and has a mean sitting clinic systolic blood pressure greater than or equal to 160 and less than or equal to 190 mm Hg at the Screening Visit and on 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 test results within the reference range for the testing laboratory or the investigator does not consider the results to be clinically significant.
Is willing to discontinue current antihypertensive medications on Day -21 or on Day -28 if is on amlodipine or chlorthalidone.

Exclusion Criteria:

Has a mean sitting clinic diastolic blood pressure greater than 119 mm Hg.
Has a baseline 24-hour ambulatory blood pressure monitoring reading of insufficient quality.
Works a night (third) shift (from 11 PM [2300] to 7 AM [0700]).
Has an upper arm circumference less than 24 cm or greater than 42 cm.
Is noncompliant with study medication during the placebo run-in period.
Has secondary hypertension of any etiology.
Has a recent history of myocardial infarction, heart failure, unstable angina, coronary artery bypass graft, percutaneous coronary intervention, hypertensive encephalopathy, cerebrovascular accident or transient ischemic attack.
Has a clinically significant cardiac conduction.
Has hemodynamically significant left ventricular outflow obstruction due to aortic valvular disease.
Has severe renal dysfunction or disease.
Has a known or suspected unilateral or bilateral renal artery stenosis.
Has a history of cancer that has not been in remission for at least 5 years prior to the first dose of study drug.
Has poorly controlled type 1 or type 2 diabetes mellitus.
Has hypokalemia or hyperkalemia.
Has an alanine aminotransferase or aspartate aminotransferase level of greater than 2.5 times the upper limit of normal, active liver disease or jaundice.
Has any other known serious disease or condition that would compromise safety, might affect life expectancy or make it difficult to successfully manage and follow the participant according to the protocol.
Has a known hypersensitivity to angiotensin II receptor blockers or thiazide-type diuretics or other sulfonamide-derived compounds.
Has been randomized in a previous Azilsartan Medoxomil study.
Is currently participating in another investigational study or has participated in an investigational study or is receiving or has received any investigational compound within 30 days prior to Randomization.
Has a history of drug abuse or a history of alcohol abuse within the past 2 years.