• Single dose: change in epinephrine, SBP, DBP, HR, and plasma nifedipine concentration time profile including Cmax and tmax under fed conditions [ Time Frame: After first dose ] [ Designated as safety issue: Yes ]
• Multi-dose: the change in norepinephrine, epinephrine, SBP, DBP, HR, and plasma nifedipine concentration time profile including Cmax and tmax under fed conditions [ Time Frame: After 2 weeks dosing ] [ Designated as safety issue: Yes ]
• The switch: the change in norepinephrine, epinephrine, SBP, DBP, HR, and plasma nifedipine concentration time profile including Cmax and tmax under fed conditions after switching from Coracten to nifedipine and vice versa [ Time Frame: Week 2 plus 1 day to week 4 ] [ Designated as safety issue: Yes ]

This study compares the effect of Adalat LA to Coracten on drug levels as well as changes in blood pressure and heart rate in fed hypertensive subjects. Subjects are dosed with either Adalat or Coracten for first 2 weeks, followed by the other drug for 2 weeks, and then switched back to the original drug for one day. Blood samples, blood pressure, and heart rate are taken before and after each treatment period.

• Drug: Adalat (Nifedipine, BAYA1040)
• Drug: Coracten

Inclusion Criteria:

• Mild to moderate hypertension (sitting DBP > 95 - <114 mmHg and/or SBP > 140 - < 160 mmHg) currently untreated. or
• Previously diagnosed mild to moderate hypertension (DBP 95-114 mmHg and/or SBP 140 - 160 mmHg) well controlled on current treatment but experiencing adverse events who can be safely switched to the study treatments. or
• Previously diagnosed mild to moderate hypertension (DBP 95-114 mmHg and/or SBP 140 - 160 mmHg), well controlled on current treatment, without adverse events, and willing to participate in the study.

Exclusion Criteria:

• Females who are pregnant, nursing or of childbearing age, unless sterilised. Subjects receiving any form of contraception are not eligible.
• Subjects with a medical history of cardiac disease within 6 months (e.g. myocarditis or pericarditis, aortic stenosis, myocardial infarction, unstable angina pectoris or severe angina pectoris).
• Subjects with history or evidence of congestive heart failure
• Subjects with evidence of clinically important arrhythmia or conduction disturbances requiring treatment.
• Subjects with severe liver disease (liver enzymes twice the upper limit of "normal") or other gastrointestinal (GI) tract diseases including inflammatory bowel disease or Crohn's disease
• Subjects with lactose intolerance.
• Subjects with renal diseases (creatinine > 1.5 mg/dL), which could alter the absorption, metabolism or excretion of the study drugs.
• Subjects with Type I diabetes.
• Subjects taking drugs which may interfere with the metabolism of nifedipine (cimetidine, ranitidine, quinidine, digoxin, rifampicin, diltiazem, cisapride, quinupristin/dalfopristin, cyclosporin, phenytoin or other antiepileptic drugs,).
• Subjects suffering from secondary or malignant hypertension.
• Subjects with any known contraindication (e.g. hypersensitivity) to nifedipine or other calcium channel blockers of the dihydropyridine class.
• Subjects with previously known clinically significant abnormalities of laboratory tests that might suggest further investigation.
• Subjects with a resting heart rate < 50 bpm or > 100 bpm.
• Subjects with a history of drug and/or alcohol abuse.
• Subjects unwilling to comply with the protocol.
• Subjects who have participated in another clinical trial within the last month.
• Subjects with neurologic or psychiatric illness requiring medication (e.g. tricyclic antidepressants, MAO inhibitors).
• Subjects with clinical evidence of ongoing or recent (within the last year) stroke or transient ischemic attacks.
• Subjects with pre-existing severe gastrointestinal or oesophageal constriction or narrowing.