Single Increasing Dose Followed by Maintenance Dose Tolerance Study of BIIR 561 CL in Healthy Male Volunteers

Inclusion Criteria: * Healthy male volunteers * Age 21 to 50 years * Broca index from -20% to +20% * Written informed consent prior to admission to the study Exclusion Criteria: * Medical examination, laboratory tests or ECG judged by the investigator to differ significantly from normal clinical values * Known gastrointestinal, hepatic, renal, respiratory, cardiovascular, metabolic, immunological or hormonal disorders * Known diseases of the central nervous system (CNS) (such as epilepsy), CNS trauma in their medical history or with psychiatric or neurological disorders * Known history of orthostatic hypotension, fainting spells or blackouts * Chronic or relevant acute infections * Allergy/hypersensitivity (including drug allergy) which is deemed relevant to the trial as judged by the investigator * Intake of a drug with a long half-life (\> 24 hours) within at least one month or less than ten half-lives of the respective drug before enrolment in the study * Intake of any other drug which might influence the results of the trial during the week previous to the start of the study * Participation in another study with an investigational drug within the last two months preceding this study * Smoker (\> 10 cigarettes or 3 cigars or 3 pipes/day) * Alcohol use of more than 60 g per day * Drug dependency * Excessive physical activities (e.g. competitive sports) within the last week before the study * Blood donation within the last 4 weeks (\>= 100 ml)