Pharmacodynamic Effects, Safety and Tolerability of Cilobradine, Compared to Metoprolol Succinate and Placebo in Healthy Volunteers

Inclusion Criteria: * All participants in the study should be healthy males and females. Volunteers will * be 21 to 55 years of age * have a Body Mass Index (BMI) of 19.9 to 29.9 kg/m2 and * have a resting heart rate (HR) (after 10 min. in the supine position) of more than 55 beats per minute (bpm) * Only post-menopausal females, or those who had had a hysterectomy, could participate. All females had to have a negative pregnancy test * In accordance with good clinical practice (GCP) and the local legislation all volunteers had to give their written informed consent prior to admission to the study Exclusion Criteria: * Any finding of the medical examination (including BP, HR and ECG) deviating from normal and of clinical relevance * Gastrointestinal, hepatic, renal, respiratory, cardiovascular, metabolic, immunological or hormonal disorders * Diseases of the central nervous system or psychiatric disorders or neurological disorders * History of relevant orthostatic hypotension, fainting spells or blackouts * Chronic or relevant acute infections * History of allergy/hypersensitivity (including drug allergy) which is deemed relevant to the trial as judged by the Investigator * Intake of drugs with a long half-life (\> 24 hours) within ten half-lives of the respective drug before enrolment in the study * Use of any drugs which might influence the results of the trial within two weeks prior to administration or during the trial * Participation in another trial with an investigational drug (≤ two months prior to administration or during the trial) * Smoker (\> 10 cigarettes or \> 3 cigars of \> 3 pipes/day) * Inability to refrain from smoking on trial days * Alcohol abuse (\> 60 g/day) * Drug abuse * Blood donation (≥ 100 ml within four weeks prior to administration or during the trial) * Excessive physical activities (within the last week before the study) * Any laboratory value outside the reference range of clinical relevance Not necessarily clinically relevant abnormalities, but specific Exclusion criteria for the drugs under study or for the study: * Consumption of more than 2 cups of coffee or black tea, or cola drinks, per day during the last 6 weeks. However, subjects may participate if abstinence from the before mentioned beverages is well tolerated during an interval of at least 2 weeks between screening and first treatment * ECG: PQ interval \> 210 ms * HR at rest \< 55 bpm * Systolic BP \< 115 mmHg * Colour vision test abnormal. However, subjects may participate if they are able to perform the flicker fusion test without difficulty * Psoriasis (own medical history or relative) * Relevant ophthalmological disease * History of asthma or obstructive pulmonary disease * History (including childhood) of traumatic injury to the head or brain * History (including childhood) of reduced seizure threshold * The following subjects will not be allowed to participate in the study * Any subject involved in professional transportation of human subjects * Any subject involved in operating dangerous machinery