Volunteers tested after eight weeks of therapy and again at the
52-week mark were just as likely to report improvement whether they
received Lyrica or a dummy drug.
The average pain intensity on a zero to 10 scale, where higher
numbers mean more pain, was 3.7 with pregabalin and 3.1 with placebo
after eight weeks of therapy. The participants started out with pain
levels of 6.3 and 6.1, respectively.
After one year, the average leg-pain intensity score was 3.4 with
pregabalin and 3.0 with placebo, according to results in the New
England Journal of Medicine.
However, pregabalin generated more side effects, with 227 adverse
events in that group compared with 124 with placebo. Dizziness was
the biggest problem.
"The lack of benefit and increased risk of harm provides a strong
case to not use this medicine in patients for sciatica," chief
author Dr. Christine Lin of the University of Sydney told Reuters
Health in an email.
Pfizer was hoping that if sciatica proved responsive to Lyrica,
"this would be a real boon to increase its use," said Dr. Bruce
Senter, an assistant professor of orthopedics at Tulane University
in New Orleans, who was not involved in the study. "Unfortunately,
this study doesn't bear out the usefulness for this."
Although tests of Lyrica from 2003 to 2010 showed that it works for
other types of pain, controlled trials conducted during the past
five years have tended to show either negative results or minimal
effects, write Drs. Nadine Attal of the University of
Versailles-Saint Quentin and Michel Barrot of the University of
Strasbourg in an accompanying editorial.
There is no definitive therapy for the radiating leg pain of
sciatica, which can also spark back pain, reflex problems, weakness
and sensory loss. The condition typically goes away in three
quarters of patients within three months.
Originally developed as a therapy for epilepsy, most prescriptions
for the $5 billion-a-year drug are now for pain relief.
Based on Australian data, perhaps 14 percent of pregabalin
prescriptions were for sciatica, Lin estimated.
In the last year or two, Senter told Reuters Health by phone, “more
people have been put on it as an as-needed analgesic. This study
seems to support that that's not a good use for it. It doesn't seem
to work that way."
[to top of second column]
In the study, volunteers from 47 sites in New South Wales were
treated for moderate-to-severe sciatica. Patients who reported
severe depression or suicidal thoughts were excluded. Since 2008 the
U.S. Food and Drug Administration has required all epilepsy drugs to
carry a warning about the risk of suicidal behavior.
All volunteers were advised to remain active and were told their
symptoms would probably diminish over time.
In addition to no difference in pain relief, pregabalin produced no
significant improvement in disability, back pain intensity, the
amount of time absent from work, the likelihood that a patient would
use other pain medications or the quality of life on either a
physical or mental scale.
"One reason we think that pregabalin does not work for sciatica is
that it has different underlying pain mechanisms than other types of
nerve pain," Lin said. "Pain mechanisms can be very complex and
influenced by a range of pathological and psycho-social factors."
Dizziness was three times more common with pregabalin, seen in four
out of 10 patients on the drug. Back pain was nearly twice as common
in these patients. None of the drug-related adverse events were
considered serious, though.
The researchers saw no increase in suicidal thinking, but the study
wasn't designed to detect that as a risk, they caution in the
report. “It is important that doctors continue to be cautious with
regard to prescribing pregabalin to patients who are susceptible to
self-harm,” the study team writes.
SOURCE: http://bit.ly/2mSr1GB New England Journal of Medicine,
online March 22, 2017
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