Proof Of Mechanism Study To Determine Efficacy Of PF-04455242 In Blocking Spiradoline (PF-00345768) Stimulated Prolactin Release

• Drug: PF-04455242
  
  Single oral 18 mg dose of PF-04455242.
• Drug: spiradoline
  
  Spiradoline 3.2 mcg/kg to be administered intramuscularly once on the morning of the spiradoline challenge day.
• Other: Placebo
  
  Oral placebo.
• Drug: PF-04455242
  
  Single 30 mg oral dose of PF-04455242.

• Experimental: PF-04455242 18 mg
  
  Subjects in this arm will receive a single 18 mg oral dose of PF-04455242 prior to spiradoline challenge
  Interventions:
  

  • Drug: PF-04455242
  • Drug: spiradoline
• Placebo Comparator: Placebo
  
  Subjects in this arm will receive placebo prior to spiradoline challenge.
  Interventions:
  

  • Other: Placebo
  • Drug: spiradoline
• Experimental: PF-04455242 30 mg
  
  Subjects in this arm will receive a single 30 mg oral dose of PF-04455242 prior to spiradoline challenge.
  Interventions:
  

  • Drug: PF-04455242
  • Drug: spiradoline

Inclusion Criteria:

• Healthy male subjects between the ages of 21 and 55 years, inclusive (Healthy is defined as no clinically relevant abnormalities identified by a detailed medical history, full physical examination, including blood pressure and pulse rate measurement, 12 lead ECG and clinical laboratory tests.

Exclusion Criteria:

• Evidence or history of clinically significant hematological, renal, endocrine, pulmonary, gastrointestinal, cardiovascular, hepatic, psychiatric, neurologic, or allergic disease (including drug allergies, but excluding untreated, asymptomatic, seasonal allergies at time of dosing).