|
 "Our systematic review found that paracetamol is ineffective for
patients with low back pain and only provides negligible benefits
for patients with lower limb osteoarthritis," said lead study author
Gustavo Machado, a researcher at the George Institute for Global
Health in Sydney, Australia.
Millions of people worldwide take the drug - known as acetaminophen
(Tylenol) in the U.S. and Japan and paracetamol (Panadol) elsewhere
- to relieve fevers as well as common aches and pains, often
purchasing it without a prescription or guidance from a clinician.
Because of side effects, including the potential for severe liver
damage, many doctors recommend that patients limit use to avoid
accidental overdoses.
"Acetaminophen, used properly, is one of the safest medications
available to treat pain, but used improperly and excessively it can
certainly be dangerous and lead to serious and life-threatening
complications," Dr. Michael Hodgman, a toxicologist at the Upstate
New York Poison Center who wasn't involved in the study, said in an
email.
Machado and colleagues analyzed data from 13 previously published
trials exploring the safety and effectiveness of acetaminophen/paracetamol
for spinal pain and osteoarthritis.
The researchers reviewed the effectiveness of the drug for
osteoarthritis of the hip or knee in ten trials covering a total of
3,541 patients. They also looked at three trials of lower back pain
with 1,825 participants, combined.
All but one of the studies involved tablets or capsules, while one
reported results of intravenous paracetamol for participants with
lower back pain.
In ten of the trials, the daily dosage was about 3,900 to 4,000
milligrams, while three studies looked at about 3,000 milligrams per
day.
In a pooled analysis, the researchers found paracetamol no better
than a placebo for lower back pain and only slightly better for
osteoarthritis, an age-related breakdown of cartilage and bone at
the joints around the hips and knees that causes pain and stiffness.
The researchers also looked at side effects across nine trials and
found no difference between paracetamol and placebo.
Combined results from three trials, however, showed that patients
taking paracetamol were four times more likely to have abnormal
liver function test results than those on placebo.
"There is some emerging evidence on harms, showing that paracetamol
is associated with increased risk of premature death, and
cardiovascular, gastrointestinal and kidney disease," Machado said
in an email. Still, clinical guidelines around the world generally
recommend the drug as good first choice for treating pain based on
the belief that it is safe, effective and affordable, he said.
[to top of second column] |
Machado’s team acknowledge some limitations in their analysis,
including the small number of trials included and their lack of
long-term follow-up.
The study also focused on chronic pain, and doesn't provide any
insight into how the drugs work for acute pain, Dr. Richard Dart,
director of the Rocky Mountain Poison and Drug Center, said in an
email.
Dart, who wasn't involved in the study, also cautioned against
reading too much into the liver findings in the analysis, noting
that no one had liver failure.
In addition, patients need to understand that, unlike aspirin and
non-steroidal anti-inflammatory drugs, paracetamol isn't designed to
relieve inflammation. It's a "weak anti-inflammatory agent but
efficacious fever medication, mainly for children," said Dr. Martin
Wehling, managing director of the Institute of Experimental and
Clinical Pharmacology and Toxicology at the University of Heidelberg
in Germany.
"Back pain has little to do with inflammation, therefore paracetamol/acetaminophen
may only work in those unidentified patients in whom chronic
processes may cause osteoarthritis even in the back," said Wehling,
who wasn't involved in the study, in an email.
It may make sense, experts said, for patients to try low doses of
paracetamol to relieve pain and to continue taking it if it works,
as long as they don't exceed the recommended daily dose.
"It is still a valuable medication as its toxicity is almost
entirely restricted to overdose issues," Wehling said. "If we had
less dangerous medications we would certainly remove paracetamol/acetaminophen
from the guidelines, but we do not have safer alternatives."
SOURCE: http://bmj.co/1NHuDCk
British Medical Journal, online March 31, 2015.
[© 2015 Thomson Reuters. All rights
reserved.] Copyright 2015 Reuters. All rights reserved. This material may not be published,
broadcast, rewritten or redistributed. |
