The primary objective of this trial is to investigate the relative bioavailability and pharmacokinetics in plasma and whole blood of BI 691751 administered as a single dose with and without food in healthy male subjects.

Inclusion criteria:

1. Healthy males according to the investigator's assessment, as based on the following criteria: a complete medical history including a physical examination, vital signs (Blood Pressure (BP), Pulse Rate (PR)), 12-lead Electrocardiogramm (ECG), and clinical laboratory tests
2. Age 18 to 50 years (incl.)
3. Body Mass Index (BMI) 18.5 to 29.9 kg/m2 (incl.)

Exclusion criteria:

1. Any finding in the medical examination (including Blood Pressure (BP), Pulse Rate (PR) and 12-lead Electrocardiogramm (ECG)) deviating from normal and judged clinically relevant by the investigator
2. Repeated measurement of systolic blood pressure greater than 140 mm Hg or diastolic blood pressure greater than 90 mm Hg
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 clinically relevant by the investigator
5. Gastrointestinal, hepatic, renal, respiratory, cardiovascular, metabolic, immunological or hormonal disorders
6. Surgery of the gastrointestinal tract that could interfere with kinetics of the study drug
7. Diseases of the central nervous system (such as epilepsy), other neurological disorders or psychiatric disorders