An open-label, long-term study examining the safety and tolerability of pregabalin in Japanese patients with central neuropathic pain

Abstract

Kenji Onouchi,1 Hiroaki Koga,2 Kazumasa Yokoyama,3 Tamotsu Yoshiyama4 1Aida Memorial Rehabilitation Hospital, Moriya, Japan; 2Kumamoto Rehabilitation Hospital, Kikuchi-Gun, Japan; 3Department of Neurology, Juntendo University School of Medicine, Tokyo, Japan; 4Pfizer Japan Inc., Tokyo, Japan Purpose: Studies of pregabalin for the treatment of central neuropathic pain have been limited to double-blind trials of 4–17 weeks in duration. The purpose of this study was to assess the long-term safety and tolerability of pregabalin in Japanese patients with central neuropathic pain. The efficacy of pregabalin was also assessed as a secondary measure. Patients and methods: This was a 53-week, multicenter, open-label trial of pregabalin (150–600 mg/day) in Japanese patients with central neuropathic pain due to spinal cord injury, multiple sclerosis, or cerebral stroke. Results: A total of 103 patients received pregabalin (post-stroke =60; spinal cord injury =38; and multiple sclerosis =5). A majority of patients (87.4%) experienced one or more treatment-related adverse events, most commonly somnolence, weight gain, dizziness, or peripheral edema. The adverse event profile was similar to that seen in other indications of pregabalin. Most treatment-related adverse events were mild (89.1%) or moderate (9.2%) in intensity. Pregabalin treatment improved total score, sensory pain, affective pain, visual analog scale (VAS), and present pain intensity scores on the Short-Form McGill Pain Questionnaire (SF-MPQ) and ten-item modified Brief Pain Inventory (mBPI-10) total score at endpoint compared with baseline. Improvements in SF-MPQ VAS and mBPI-10 total scores were evident in all patient subpopulations. Mean changes from baseline in SF-MPQ VAS and mBPI-10 scores at endpoint were –20.1 and –1.4, respectively. Conclusion: These findings demonstrate that pregabalin is generally well tolerated and provides sustained efficacy over a 53-week treatment period in patients with chronic central neuropathic pain. Keywords: clinical trial, spinal cord injury, multiple sclerosis, cerebral stroke