The proposed study will evaluate the safety, tolerability, pharmacokinetics (PK) and pharmacodynamics of repeated oral doses of GSK618334 in healthy male and female volunteers.

GSK618334 strongly binds to dopamine type 3 receptors in the human brain and is being developed as an innovative treatment for substance dependence. This study will evaluate the safety, tolerability, blood concentrations and effect following repeated oral doses of GSK618334 in healthy male and female volunteers. The effect of food on a single oral dose of GSK618334 will also be evaluated. Another portion of this study will investigate dopamine type 3 receptor binding in the human brain by PET scan before and after repeated doses of GSK618334.

Inclusion Criteria:

• Healthy Males and Females between the ages of 18-50 years old
• Male and Female subjects must agree to use protocol specified contraceptive methods.
• Male subjects only in PET parts of the study.
• Capable of providing written informed consent.

Exclusion Criteria:

• A positive test for Hepatitis B or Hepatitis C within 3 months of screening.
• Current or chronic history of liver disease, or known liver/bile/gallbladder abnormalities.
• Personal or family history of heart disease (such as irregular heart beats, a history of sudden unexplained death in a first degree relative, or unexplained fainting).
• Screening ECG parameters outside the protocol specified parameters.
• Pulse rate <50 or >100 bpm OR a systolic blood pressure >140 or <95 mmHg OR a diastolic blood pressure >90 or <50 mmHg at screening and/or baseline.
• Pregnant or lactating females.
• Exposure to more than four new chemical entities within 12 months prior to the first dosing day.
• Where participation in the study would result in donation of blood or blood products in excess of 500 mL within a 56 day period.
• Previous inclusion in a research and/or medical protocol involving nuclear medicine, PET or radiological investigations with significant radiation burden.
• Significant suicidal risk.

Patient-level data for this study will be made available through www.clinicalstudydatarequest.com following the timelines and process described on this site.