Evaluate the safety and tolerability of PF-04447943 after administration of multiple doses in healthy elderly participants. Evaluate plasma drug levels and effects on cognition.

Inclusion Criteria:

• Healthy male and/or female subjects.
• Subjects must be in reasonably good health as determined by the investigator based on medical history, full physical examination (including blood pressure and pulse rate measurement), 12 lead ECG and clinical laboratory tests.
• Subjects with mild, chronic, stable disease (eg, controlled hypertension, non-insulin dependent diabetes, osteoarthritis may be enrolled if deemed medically prudent by the investigator.
• Subjects taking daily prescription or non-prescription medications for management of acceptable chronic medical conditions must be on a stable dose.
• Body Mass Index (BMI) between 18 to 30 kg/m2, inclusive; and a total body weight >50 kg (110 lbs).
• Creatinine clearance greater than 30 mL/min using the Cockcroft-Gault method.

Exclusion Criteria:

• Subjects with evidence or history of clinically significant hematological, renal, endocrine, pulmonary, gastrointestinal, cardiovascular, hepatic, psychiatric, neurologic, immunologic, or allergic disease.
• Use of tobacco or any form of nicotine in the past 6 months.
• Greater than 7 drinks of alcohol per week for women, and greater than 14 drinks of alcohol per week for men.