Results Offer Hope to Patients with Excruciating Chronic Pain
SYDNEY, Australia, Nov. 28 /Xinhua-PRNewswire/ -- Findings from a new
study published today in the journal Neurology demonstrate that the oral
medication pregabalin is significantly effective in relieving central
neuropathic (nerve) pain and improves pain-related sleep disturbance and
anxiety in patients with spinal cord injury. Conducted by researchers at the
Pain Management Research Institute in Sydney, the study is the largest
controlled clinical trial ever of patients with spinal cord injury who suffer
from central neuropathic pain, a particularly persistent and severe pain
condition.
Results from the study showed that patients using pregabalin (150-600
mg/day) experienced significant improvements in symptoms as early as the
first week of treatment and those improvements were sustained throughout the
study. Patients taking pregabalin experienced a significant reduction in the
average intensity of their pain and significant improvements in pain-related
sleep interference as well as a reduction in anxiety compared to those taking
placebo.
"Historically it has been extremely difficult to manage patients with
central neuropathic pain due to a lack of effective treatments and many
people with spinal cord injury have excruciating pain," said Prof. Philip
Siddall, lead investigator of the study and Clinical Associate Professor at
the Pain Management Research Institute in Sydney. "The study demonstrates
that pregabalin is an effective and well-tolerated therapy for treating a
range of symptoms that can negatively impact overall quality of life. This
study is an important step forward for clinicians trying to improve the lives
of patients suffering from difficult-to-treat nerve pains."
Approximately two-thirds of patients with spinal cord injury often suffer
from severe central neuropathic pain(1,2), which is caused by a lesion or
dysfunction in the central nervous system(3). Patients often describe the
symptoms of their pain as burning, tingling, stabbing, shooting, pricking,
scalding and freezing(4,5,6). Chronic pain following spinal cord injury may
limit a patient's ability to perform daily activities(7). Consequently,
quality of life may be impaired(8). Central neuropathic pain can occur in
patients with spinal cord injury, stroke, multiple sclerosis and neoplasia.
Pregabalin is believed to work by calming hyper-excited neurons or nerve
cells which may be an underlying cause for various types of nerve pain.
Based on the results of this study, pregabalin recently became the only
therapy to receive European regulatory approval in central neuropathic pain.
About the Study
The study, sponsored by pregabalin (Lyrica(R)) developer Pfizer Inc, was
a multicentre, parallel-group, double-blind, randomised clinical trial
comparing pregabalin with placebo over a 12-week treatment period in patients
with spinal cord injury who had central neuropathic pain as defined by the
International Association for the Study of Pain classification. The 12-week
treatment period was preceded by a 1-week baseline period during which
baseline data were collected. Patients were randomised to receive either
flexible dose pregabalin (150-600 mg/day) (n=70) or placebo (n=67) taken
twice daily. The primary endpoint of the study was mean pain score as
measured by patient pain diary assessments which were completed daily.
Patients also rated the extent to which pain interfered with sleep in a daily
diary. Changes in anxiety were evaluated using the Hospital Anxiety and
Depression Scale (HADS).
Results from the study showed that:
* Patients receiving pregabalin experienced significant improvements in
symptoms as early as the first week of treatment and those improvements
were sustained throughout the study
* Patients receiving pregabalin experienced a significant reduction in
the average intensity of their pain and significant improvements in
pain-related sleep interference (p<0.001) as well as a reduction in
anxiety (p<0.05) compared to those taking placebo (p<0.001)
* More than 40 percent of patients had greater than a 30 percent
reduction in pain as compared to 16 percent of patients on placebo
(p=0.001)
* At the end of the study, three times less patients had severe pain in
the pregabalin group compared with the placebo group
* Pregabalin was associated with a rapid and significant reduction in
pain-related sleep interference (p<0.001) as well as a reduction in
anxiety (p<0.05) compared to those patients taking placebo
* The most common adverse events were somnolence and dizziness, which
were typically mild to moderate and transient.
About the Pain Management Research Institute
The Pain Management Research Institute (PMRI) is headed by Professor
Michael Cousins and brings together around 40 researchers and 40 clinical
staff who are involved in pain research and management (
http://www.pmri.med.usyd.edu.au ). The Institute also has a strong focus on
education and has a number of staff involved in the delivery of a
postgraduate degree program in Pain Management through the University of
Sydney. This course is delivered on-line and accessible to students
internationally. In 2004 the PMRI Educational Program received an
international award as an "Exemplary Educational Program". Since 2005, the
education program has been available to European and North American students
through collaborations with the University of Edinburgh and the University of
California, San Francisco.
The pain research program of the PMRI has a broad scope and has a number
of teams investigating various aspects of pain epidemiology, neurobiology,
psychology and treatment and has gained international recognition for its
work in several areas including pain following spinal cord injury. In 1998,
the Centre gained one of only eight National Health & Medical Research
Council (NHMRC) of Australia awards as a "Centre of Clinical Excellence in
Hospital Based Research". In 2005, the PMRI, in collaboration with the
University of Queensland (Australia), University College London (UK) and
Nagasaki University (Japan) was a recipient of an NHMRC Program Grant (2005-
2009). Also in 2005 PMRI was the top level funded institution for a Program
Grant from the NSW Health to investigate "Mechanisms and Treatment of Pain
Associated with Spinal Cord Injury" (2005-2008).
The Pain Management & Research Centre (PMRC) is the clinical arm of the
PMRI and conducts clinical treatment programs in acute pain, cancer pain and
chronic non cancer pain. PMRC comprises a group of approx 40
multidisciplinary health care practitioners who evaluate all aspects of each
patient's pain and recommend treatment options based upon a multidisciplinary
approach. PMRC currently provides approx 40,000 episodes of patient care per
annum. Each year at least four internationally funded Fellows spend a year
of training with PMRC. To date Fellows have been drawn from more than 20
countries.
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report and the relationship of pain to physician factors in the first
6 months following spinal cord injury. Pain 1999;81(1-2):187-197.
3 Merskey H, Bogduk N, eds. Classification of chronic pain. Descriptions
of chronic pain syndromes and definitions of pain terms. Seattle: IASP
Press, 1994:209-212.
4 Cruz-Almeida Y, Martinez-Arizala A, Widerstrom-Noga EG. Chronicity of
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5 Finnerup N, Johannesen I, Fuglsang-Frederiksen A, Bach FW, Jensen T.
Sensory function in spinal cord injury patients with and without pain.
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6 Siddall P, McClelland JM, Rutkowski S, Cousins M. A longitudinal study
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7 Ravensscroft A, Ahmed YS, Burnside IG. Chronic pain after SCI: a
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