Neuralgia, Postherpetic

• Pfizer Investigational Site — Phoenix, Arizona, United States
• Pfizer Investigational Site — Little Rock, Arkansas, United States
• Pfizer Investigational Site — Duarte, California, United States
• Pfizer Investigational Site — Denver, Colorado, United States

• Medical Corporation Fujigaki Clinic — Ōita, Japan

• Odense University Hospital — Odense, Funen, Denmark

• Marwa Eid — Cairo, Egypt

• Albany Medical College — Albany, New York, United States

Not specified

• Asan medical center — Seoul, South Korea
• Seong-Soo Choi — Seoul, South Korea

Not specified

• Republican Clinical Hospital — Chisinau, Moldova

• The second affiliated hospital of Zhejiang University — Hangzhou, Zhejiang, China