This study investigates whether YM178 has an effect on the pharmacokinetics of warfarin, to exclude any drug-drug interaction between YM178 and warfarin, and evaluates the safety and tolerability of warfarin alone and combined with YM178.

Inclusion Criteria:

• Female subject must be of non-child bearing potential, i.e. postmenopausal, surgically sterilized (e.g. tubal ligation), hysterectomy in medical history, or must practice adequate (double barrier) non-hormonal contraceptive methods to prevent pregnancies.
• Body Mass Index (BMI) ≥ 18.5 and < 30 kg/m2, inclusive

Exclusion Criteria:

• Female who is pregnant
• Any of the liver function tests (i.e. alanine aminotransferase (ALT), aspartate aminotransferase (AST) and Alkaline Phosphatase (AP)) above the upper limit of normal (ULN)
• Any clinically significant history of disease or disorder - gastrointestinal, cardiovascular, respiratory, renal, hepatic, neurological, dermatological, psychiatric or metabolic as judged by the medical investigator
• Abnormal pulse and/or blood pressure measurements and the pre-study as follows: Pulse < 40 or > 90 bpm; mean systolic blood pressure > 140 mmHg; mean diastolic blood pressure > 90 mmHg (blood measurements taken in triplicate after subject has been resting in supine position for 5 min; pulse will be measured automatically
• A marked baseline prolongation of QT/QTc interval after repeated measurements of >450 ms, a history of unexplained syncope, cardiac arrest, unexplained cardiac arrhythmias or torsades de pointes, structural heart disease, or a family history of Long QT Syndrome (LQTS)
• Use of any prescribed or OTC (over-the counter) drugs (including vitamins, natural and herbal remedies, e.g. St. John's wort) in the 2 weeks prior to admission to the Clinical Unit, except for paracetamol (up to 3 g/day)
• Any use of drugs of abuse within 3 months prior to admission to the clinical unit
• History of smoking more than 10 cigarettes (or equivalent amount of tobacco) per day within 3 months prior to admission to the clinical unit
• History of drinking more than 21 units of alcohol per week (1 unit = 270 ml of beer or 40 ml of spirits or 1 glass of wine) (> 14 units of alcohol for female subjects) within 3 months prior to admission to the clinical unit
• Donation of blood or blood products within 3 months prior to admission to the clinical unit