Wednesday 12 May 2010, 10:15AM
PEARLS No. 242, April 2010, written by Brian R McAvoy
Clinical question
How effective are oral or transdermal opioids in patients with
osteoarthritis (OA) of the knee or hip?
Bottom line
Compared to placebo or no intervention, the small to moderate
beneficial effects in terms of pain relief (NNT* 8) and improvement
in function (NNT 10) of opioids were outweighed by large increases
in the risk of adverse events (NNH** 12 for any adverse events and
NNH 19 for withdrawal because of adverse events). There were no
substantial differences in effects according to type of opioid,
analgesic potency (strong or weak), daily dose, duration of
treatment or follow-up, methodological quality of trials, and type
of funding. Withdrawal symptoms were more severe after fentanyl
treatment compared to placebo. Preparations studied included oral
codeine, morphine, oxymorphone, oxycodone and transdermal fentanyl.
Tramadol was excluded. A 2009 Cochrane Review¹ found the benefits
of tramadol were comparable with those obtained with paracetamol
and these benefits were coupled with a less favourable safety
profile. *NNT = number needed to treat to benefit 1 individual
**NNH = number needed to treat to cause harm in 1 individual
Caveat
The treatment durations were relatively short (3 days to 3 months;
median 4 weeks). The reporting of safety outcomes was incomplete,
with adverse events reported in 4 trials, and serious adverse
events in 3 trials only. Most of the trials were funded by the
pharmaceutical industry. While no evidence of long term effects is
available from randomised trials, observational studies indicate
long term treatment (>6 months) with opioids for chronic
conditions, such as OA, may have deleterious effects, including
poorer quality of life and reduced functional capacity, and does
not seem to improve pain relief.²
Context
OA is the most common form of joint disease and the leading cause
of pain and physical disability in the elderly. Opioids may be a
viable treatment option if patients suffer from severe pain, or if
other analgesics are contraindicated. However, the evidence on
their effectiveness and safety is contradictory.
Cochrane Systematic Review
Nuesch E et al. Oral or transdermal opioids for osteoarthritis of
the knee or hip. Cochrane Reviews 2009, Issue 4. Article No.
CD003115. DOI:10.1002/14651858.CD003115.pub3. This review contains
10 studies involving 2268 participants.
Further references
1. Cepada MS et al. Cochrane Reviews 2009, Issue 3. Article No.
CD005522. DOI: 10.1002/14651858.CD005522.pub2.
2. Eriksen J et al. Pain 2006;125:172Ð79.