Study to Investigate Safety With Special Emphasis on ECG Effects and Tolerability After Oral Doses of Dextromethorphan Hydrobromide Monohydrate in Healthy Male and Female Subjects

Inclusion Criteria: * Healthy males and females according to the following criteria: Based upon a complete medical history, including the physical examination, oral body temperature, vital signs (blood pressure, pulse rate), 12-lead Electrocardiogram (ECG), clinical laboratory tests * Age ≥18 and Age ≤55 years * BMI ≥18.5 and BMI ≤30 kg/m2 (Body Mass Index) * Extensive or poor metabolisers for CYP 2D6 based on the results of a genotyping test * Signed and dated written informed consent prior to admission to the study in accordance with Good Clinical Practice (GCP) and the local legislation Exclusion Criteria: * Any finding of the medical examination (including blood pressure, pulse rate and ECG) deviating from normal and of clinical relevance * Any evidence of a clinically relevant concomitant disease * Gastrointestinal, hepatic, renal, respiratory, cardiovascular, metabolic, immunological or hormonal disorders * Surgery of the gastrointestinal tract (except appendectomy) * Diseases of the central nervous system (such as epilepsy) or psychiatric disorders or neurological disorders * History of relevant orthostatic hypotension, fainting spells or blackouts * Chronic or relevant acute infections * History of relevant allergy/hypersensitivity (including allergy to drug or its excipients) * Intake of drugs with a long half-life (\> 24 hours) within at least one month or less than 10 half-lives of the respective drug prior to administration or during the trial * Use of drugs which might reasonably influence the results of the trial or that prolong the QT/QTc interval based on the knowledge at the time of protocol preparation within 10 days prior to administration or during the trial * Participation in another trial with an investigational drug within one month prior to first administration or during the trial * Smoker (\> 10 cigarettes or \> 3 cigars or \> 3 pipes/day) * Inability to refrain from smoking on trial days * Alcohol abuse (more than 60 g/day) * Drug abuse * Blood donation (more than 100 mL within four weeks prior to first administration or during the trial) * Excessive physical activities (within one week prior to first administration or during the trial) * Any laboratory value outside the reference range that is of clinical relevance * Inability to comply with dietary regimen of trial site * A marked baseline prolongation of QTc interval of \>450 ms; * A history of additional risk factors for Torsades de points (e.g., heart failure, hypokalemia, family history of Long QT Syndrome) Exclusion criteria specific for this study: * Use of drugs that inhibit or induce cytochrome P 450 enzymes, especially CYP2D6, within 30 days prior to first administration of the study medication or during the trial For female subjects: * Pregnancy or planning to become pregnant within 2 months of study completion * Positive pregnancy test * No adequate contraception in woman of child bearing potential during the study, i.e., sterilisation, intrauterine device, injectables, oral contraceptive combined with a barrier method of contraception * Lactation period