The efficacy and safety of Telmisartan capsule in patients with essential hypertension were evaluated in comparison with Enalapril Maleate in the double blind trial.

Inclusion Criteria:

• Patient is ≥ 25 years of age
• Patient is either male or female
• Outpatient. Change to inpatient is not allowed during the study period
• Blood pressure is measured 3 times or more during the 4-week observation period; the last 2 measurements in the sitting position (intervals between measurements must be less than 4 weeks) are stabilized for both of systolic pressure (within +/- 30 mmHg) and diastolic pressure within +/- 15 mmHg) with the mean exceeding 160 mmHg for systolic and 95 mmHG for diastolic pressure

Exclusion Criteria:

• Patient has severe hypertension (the last 2 measurements in the observation period exceed 120 mmHg in terms of diastolic blood pressure)
• Patient has secondary or malignant hypertension
• Patient has a history of severe cardiac failure, unstable angina, or myocardial infarction within previous six months
• Patient has atrioventricular conduction disturbance, atrial fibrillation or severe arrhythmia
• Patient has any symptoms of cerebrovascular disorder
• Patient has serious hepatic dysfunction (either GOT (glutamic-oxaloacetic transaminase) or GPT (glutamic-pyruvic transaminase) exceeds 100 U)
• Patient has renal dysfunction (serum creatinin ≥ 2.1 mg/dl)
• Patient has uncontrolled diabetic (either of the following tests exceeds the specified standards: fasting blood glucose exceeding 151 mg/dl or HbA1c exceeding 8%)
• Patient has a history of drug sensitivity to ACE (angiotensin converting enzyme) inhibitors and angiotensin II receptor antagonists
• Patient has a history of angioedema due to ACE inhibitors
• Patient has hyperkalemia (K exceeding 5.5 mEq/l)
• Patient has received enalapril just before the start of observation period
• Patient has received treatment with any other investigational drug(s) within three months of the start of observation period
• Patients is pregnant, breast-feeding, or possible pregnant, or wants to be pregnant during the study period
• Patient has any other condition that the investigator or subinvestigator feels would be inappropriate for the study participation