General Objective:
To determine the effectiveness of drug treatment in the management of MS-induced neuropathic
pain.
Specific Objectives:
Comparatively assess the effectiveness and safety profile of pregabalin (Lyrica) and
paroxetine (Paxil) in managing MS-induced neuropathic pain.
Comparatively assess the effectiveness of pregabalin (Lyrica) and paroxetine (Paxil) in
improving the quality-of-life associated with MS-induced neuropathic pain.
Study Design:
A comparative single center, randomized, open-label study involving patients with multiple
sclerosis (MS) - induced neuropathic pain receiving treatment with either pregabalin
(Lyrica®) or paroxetine (Paxil®).
The study will run for approximately one year, requiring individual participants' involvement
for 8 weeks.
Participant Selection:
Individuals with clinically definite MS presenting with symptoms of neuropathic pain (as
determined by clinician) that express interest in the study will be screened for eligibility.
Inclusion Criteria:
Patients presenting with symptoms of neuropathic pain as determined by clinician, with a
minimum VAS pain score of 40mm as determined by a baseline score (0mm = no pain, 100mm =
worst pain).
Male and female patients between the ages of 18 and 65 years old.
Clinically definite multiple sclerosis as defined by clinical history review,
neurological examination and positive MRI.
EDSS scores of < 6.0.
No known hypersensitivity to the study medications.
Negative serum pregnancy test for all female patients of childbearing age; not currently
breastfeeding.
Not currently treated with pregabalin, gabapentin, paroxetine or another SSRI.
No previous treatment failures with pregabalin or paroxetine.
Baseline creatinine clearance (Clcr) of > 50mL/min.
No significant hepatic insufficiency.
If on other pain medications, must be on stable dose for at least 6 months and other
medications must not elicit significant drug-drug interactions with study medications.
Study Procedures:
After obtaining informed consent (Visit 1), participants undergo various assessments,
including pain/quality-of-life analyses (SF-MPQ, SF-36, VAS), physical/neurological exam and
a standard blood test. Based on above inclusion criteria, participants will be randomized to
either Group A (paroxetine) or Group B (pregabalin). Participants will be provided with
prescriptions for assigned study medications as well as dosing instructions. A pain diary
consisting of a single VAS scale will be provided to the participants, which are to be
completed daily upon waking and should be used to rate the individual's average pain over the
last 24 hours. Dosages of study medications will be titrated slowly over 3 weeks to lower
likelihood of adverse events. After the three week titration phase, participants will return
to the clinic (Visit 2) for a follow-up. Pain/quality-of-life assessments (as at Visit 1)
will be completed again at this visit. In addition, average pain scores will be determined
from daily pain diaries. Adverse events will be discussed and individual tolerability will be
assessed. At this point, it will be determined if the patient will be maintained at the
target dosage or if the dosage will be lowered to accommodate patient tolerability.
Participants will be maintained at determined maintenance dose for 5 weeks, after which they
will return to the clinic (Visit 3) for a final follow-up assessment. Participants will
complete final pain/quality-of-life assessments, as well as the "Patient-rated Global
Impression of Change". Adverse events and average pain scores will be reviewed. At the
conclusion of the 8-week treatment phase, participants will have the option of remaining on
their current study medication or be tapered off.