Intervention: Olmesartan
Trial phase: Phase 3
ATC code: C09CA08 | C09DA08 | C09DB02 | C09DX03
SMILES: CCCc1nc(C(C)(C)O)c(C(=O)O)n1Cc1ccc(-c2ccccc2-c2nnn[nH]2)cc1
Sex: All
Age groups: Adult | Older Adult
Healthy volunteers: No
Participants at risk: 290
Group description: Olmesartan 20 mg, tablets and matching placebo comparator, orally, once daily for two weeks.

Increased to Olmesartan 40 mg, tablets and matching placebo comparator, orally, once daily for up to four weeks.
Eligibility criteria:
Inclusion Criteria:

Essential hypertension (sitting systolic blood pressure between 150 and 180 mm Hg, inclusive, at Day -1 and 24-hour mean systolic blood pressure between 130 and 170 mm Hg, inclusive, at Day 1).
Capable of understanding and complying with protocol requirements.
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
Clinical laboratory evaluations within the reference range for the testing laboratory or the results are deemed not clinically significant for inclusion into this study by the investigator.
Willing to discontinue current antihypertensive medications at Screening Day 21 visit. If the participant is on amlodipine prior to Screening, the participant is willing to discontinue this medication at Screening Day -28.

Exclusion Criteria:

Sitting diastolic blood pressure greater than 114 mm Hg at Day -1 (day prior to Randomization).
Baseline 24-hour ambulatory blood pressure monitor reading of insufficient quality.
Taking or expected to take an excluded medication as described in the Excluded Medications.
Hypersensitive to angiotensin II receptor blockers.
History 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.
Hemodynamically significant left ventricular outflow obstruction due to aortic valvular disease.
Secondary hypertension of any etiology.
Noncompliant (less than 70% or greater than 130%) with study medication during run-in period.
Moderate to severe renal dysfunction or disease.
Known or suspected unilateral or bilateral renal artery stenosis.
History of drug or alcohol abuse 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 participants with basal cell or stage I squamous cell carcinoma of the skin).
Type 1 or poorly-controlled type 2 diabetes mellitus (glycosylate hemoglobin greater than 8.0%) at Screening.
Hyperkalemia as defined by the central laboratory normal reference range at Screening.
Alanine aminotransferase level of greater than 2.5 times the upper limit of normal, active liver disease, or jaundice at Screening.
Upper arm circumference less than 24 cm or greater than 42 cm.
Works night (3rd) shift (defined as 11 PM [2300] to 7 AM [0700]).
Unwilling or unable to comply with the protocol or scheduled appointments.
Currently is participating in another investigational study or has participated in an investigational study within 30 days prior to Randomization.
Any other serious disease or condition at Screening or Randomization that would compromise participant's safety, might affect life expectancy, or make it difficult to successfully manage and follow the subject according to the protocol.
Has been randomized in a previous azilsartan medoxomil study.
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.