To assess the influence of BI 187004 on kinetics of cytochrome P450 (CYP) and P glycoprotein (P-gp) probe drugs as a means of predicting drug-drug interactions.

Inclusion criteria:

1. healthy male subjects
2. age of 18 to 55 years
3. body mass index of 18.5 to 29.9 kg/m2
4. Subjects must be able to understand and comply with study requirements

Exclusion criteria:

1. Any finding in the medical examination (including BP, PR or ECG) is deviating from normal and judged as clinically relevant by the investigator
2. Repeated measurement of systolic blood pressure outside the range of 90 to 140 mmHg, diastolic blood pressure outside the range of 50 to 90 mmHg, or pulse rate outside the range of 50 to 90 bpm
3. Any laboratory value outside the reference range that the investigator considers to be of clinical relevance
4. Any evidence of a concomitant disease judged as clinically relevant by the investigator
5. Gastrointestinal, hepatic, renal, respiratory, cardiovascular, metabolic, immunological or hormonal disorders
6. Cholecystectomy and/or surgery of the gastrointestinal tract that could interfere with pharmacokinetics of the trial medication (except appendectomy and simple hernia repair)
7. Diseases of the central nervous system (including but not limited to any kind of seizures or stroke), and other relevant neurological or psychiatric disorders