Paracetamol should be the first drug tried for pain relief in osteoarthritis
(OA), according to guidelines from the American College of Rheumatology (ACR).
The ACR says that although a number of patients fail to obtain adequate pain
relief even on full doses of paracetamol, based on the drugs overall cost, efficacy
and toxicity profile, it should be tried as initial therapy. For many patients,
paracetamol is comparable with non-steroidal anti-inflammatory drugs (NSAIDs)
in terms of relief of mild to moderate OA pain, it adds.
The ACR guidelines, which were published in September, are the first to consider
the use of COX-2 specific inhibitors in the treatment of OA. They recommend
that COX-2 inhibitors are one of a number of drug groups that should be considered
for patients who are at increased risk of a serious upper gastrointestinal adverse
event. Other therapies that fall into this group are paracetamol, non-selective
NSAIDs given with misoprostol or a proton pump inhibitor, non-acetylated salicylate,
intra-articular opioids, glucocorticoids, hyaluronic acid or topical capsaicin
or methylsalicylate. The ACR says that COX-2 inhibitors appear to be better
tolerated than comparative non-selective NSAIDs, with lower incidence of dyspepsia
and other gastrointestinal side effects. However, it cautions that renal toxicity
remains a risk. In patients who are not at increased risk of an upper gastrointestinal
adverse event, use of gastroprotective therapy with NSAIDs is not recommended.
The guidelines state that for patients who fail to obtain adequate symptom relief
with paracetamol, the choice of alternative or additional pharmacological agents
should be made after evaluating risk factors for gastrointestinal and renal
toxicity. It is reasonable to use drugs for OA in combination, with the exception
of NSAIDs where only a single agent should be used, they say. Low-dose aspirin
for cardiac disease may be taken with an NSAID although this may increase the
risk of gastrointestinal bleeding.
In July, the European League Against Rheumatism (EULAR) recommended the use
of paracetamol as first-line drug treatment of OA of the knee (PJ, July 15,
p102). The
ACR guidance is available on the internet