Study to Assess the Influence of Three Different α-antagonists and Placebo on the Extent of Weekly Phenylephrine-induced Mydriasis at Three Different Concentrations of Phenylephrine in Healthy Male Volunteers

Inclusion criteria

• Healthy male
• Age ≥ 21 and ≤ 55 years
• Body Mass Index (BMI) ≥ 18.5 and ≤ 29.9 kg/m2
• Signed and dated written informed consent in accordance with Good Clinical Practice (GCP) and local legislation

Exclusion criteria

• Any finding of the medical examination (including blood pressure, pulse rate and Electrocardiogram (ECG)) deviating from normal and of clinical relevance
• Gastrointestinal, hepatic, renal, respiratory, cardiovascular, metabolic, immunological or hormonal disorders
• Diseases of the central nervous system (such as epilepsy) or psychiatric disorders or neurological disorders
• History of 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 (> 24:00 hours) within at least one month or less than ten half-lives of the respective drug before enrolment in the study or during the study
• Use of any drugs which might influence the results of the trial up to seven days prior to enrolment in the study or during the study
• Participation in another trial with an investigational drug (≤ two months prior to administration or during the trial)
• Smoker (> 10 cigarettes or > 3 cigars or > 3 pipes/day)
• Inability to refrain from smoking on in-house trial days
• Alcohol abuse (> 60 g/day)
• Drug abuse
• Blood donation (≥ 100 mL within four weeks prior to administration or during the trial)
• Any laboratory value outside the clinically accepted reference range
• Excessive physical activities within the last week before the trial or during the trial

The following exclusion criteria are of special interest for this study:

• Hypersensitivity to any alpha agonist, or to phenylephrine
• Supine blood pressure at screening of systolic < 110 mmHg and diastolic < 60 mmHg
• Ophthalmological criteria:

• Corrected visual acuity < 0.5
• Refractive Error with a spherical equivalent > +6 or smaller - 6 D
• Elevated intraocular pressure (higher than 22 mmHg)
• Relevant anisocoria or pupil deformation
• History of eye surgery apart from laser trabeculoplasty less than three months previously or extraocular surgery such as strabismus surgery
• Topical ocular medication influencing IOP (intraocular pressure) or pupil size within 3 months prior to study-start