Inclusion Criteria:

• Male and female subjects between 18 and 75 years of age, inclusive
• Have a documented history of rheumatoid arthritis (diagnosed according to American College of Rheumatology criteria) for at least 6 months before study entry
• Have painful rheumatoid arthritis with pain predominantly in the lower extremities (ie, hip, knees, ankles, and/or feet)
• Have a lower extremity pain intensity score of 5 or higher on a pain rating scale completed on Day 1 of Part A before dosing (after resting for 45 minutes and then walking for at least 10 minutes on a treadmill)and then have a minimum ELEPI score of 4 on other visits in Part A
• If receiving disease modifying antirheumatic drugs, have a stable dose regimen for at least 30 days before study entry (90 days before study entry for biologic therapy)
• If biologic therapy has been recently discontinued, Enbrel™ or Orencia™ must have been discontinued at least 30 days before study entry, and Humira™, Remicade™, and Rituxan™ must have been discontinued at least 60 days before study entry
• For male subjects, be surgically sterile or agree to use an appropriate method of contraception
• For female subjects of childbearing potential, be surgically sterile or using an intrauterine device, or injectable, transdermal, or combination oral contraceptive deemed highly effective by the FDA
• Have a body weight of at least 45 kg
• Be able to understand and comply with the protocol requirements (such as repeated treadmill walking and diary completion via the interactive voice response system), instructions, and protocol specified restrictions.

Exclusion Criteria:

• Have an overall pain intensity score equal to 10 at screening or before the first dose of study medication in Part A
• Have a pain intensity score for the upper body (ie, back, neck, fingers, wrists, elbows, and/or shoulders) above 7 on a pain rating scale before study medication administration
• Have a history of headache requiring prescription treatment within 6 months of study entry
• Have significant renal disease (as indicated by blood urea nitrogen or serum creatinine ≥ 2 times the upper limit of normal) or have significant hepatic disease (as indicated by liver function test results ≥ 2 times the upper limit of normal)
• Have low blood pressure symptoms when going from a sitting position to standing
• Have a history of a seizure disorder, including febrile seizures
• Have, as determined by the investigator or the sponsor's medical monitor, a history or clinical manifestations of significant renal, hepatic, cardiovascular, metabolic, neurologic, psychiatric, or other conditions that would affect study participation
• Are taking cytochrome P450 (CYP) 3A4/5 or P glycoprotein (P gp) transporter inhibitors
• Have taken oral steroids within 30 days of study entry or intra articular steroids within 60 days of study entry (inhaled or topical steroids or stable oral dose ≤ 10 mg is permitted)
• Have a history or presence of allergy or intolerance to nonsteroidal anti inflammatory drugs or acetaminophen, or have a history of drug or other allergy that, in the opinion of the investigator, contraindicates participation in the study
• Have a history of alcoholism or drug addiction or abuse within 5 years before the scheduled administration of study medication
• Have participated in a trial of any investigational medication within 30 days before study drug administration