Long-term Study of CS-3150 as Monotherapy or in Combination With Other Antihypertensive Drug in Japanese Patients With Essential Hypertension

Inclusion Criteria: * Male and female subjects aged 20 years or older at informed consent * Subjects with essential hypertension, who do not receive any antihypertensive drugs or receive calcium channel blocker, angiotensin converting enzyme ACE inhibitor, or angiotensin-II receptor blockade ARB during run-in period (Sitting systolic blood pressure SBP ≥ 140 mmHg and \< 180 mmHg, Sitting diastolic blood pressure DBP ≥ 90 mmHg and \< 110 mmHg, and mean 24hr SBP ≥ 130 and DBP ≥ 80 mmHg) Exclusion Criteria: * Secondary hypertension or malignant hypertension * Diabetes mellitus with albuminuria * Serum potassium level \< 3.5 or ≥ 5.1 mEq/L (≥ 4.8 mEq/L if receive ACE inhibitor, or ARB) * Reversed day-night life cycle including overnight workers * estimated glomerular filtration rate eGFR \< 60 mL/min/1.73 m\^2.