Efficacy of opioids versus placebo in chronic pain: a systematic review and meta-analysis of enriched enrollment randomized withdrawal trials – free full-text /PMC5939920/ – J Pain Res. May 2018
This most recent study contradicts all the hype saying that opioids aren’t effective for our chronic pain:
- “Opioids are efficacious in the treatment of chronic non-cancer pain for up to 3 months in randomized controlled trials”
- “Opioids … remain an important therapeutic option.”
- “I…the efficacy of opioids is at least as large as that of any other treatment for chronic pain.”
Opioids have been used for millennia for the treatment of pain. However, the long-term efficacy of opioids to treat chronic non-cancer pain continues to be debated.
To evaluate opioids’ efficacy in chronic non-cancer pain, we performed a meta-analysis of published clinical trials for μ-opioid receptor agonists performed for US Food and Drug Administration approval.
MEDLINE and Cochrane trial register were searched for enriched enrollment randomized withdrawal studies (before June 2016). Selection criteria included: adults, ≥10 subjects per arm, any chronic pain condition, double-blind treatment period lasting ≥12 weeks, and all μ-agonist opioids approved in the USA.
Fifteen studies met criteria.
Opioid efficacy was statistically significant (p<0.001) versus placebo for
- pain intensity (standardized mean difference: −0.416),
- ≥30% and ≥50% improvement in pain (risk difference: 0.166 and 0.137),
- patient global impression of change (0.163), and
- patient global assessment of study medication (0.194).
There were minor benefits on physical function and no effect on mental function.
Opioids are efficacious in the treatment of chronic non-cancer pain for up to 3 months in randomized controlled trials. This should be considered, alongside data on opioid safety, in the use of opioids for the treatment of chronic pain.
Opioids have been used for millennia for the treatment of pain and remain an important therapeutic option.
- the American Academy of Pain Medicine,
- the American Pain Society,
- the US Federation of State Medical Boards, and
- the Centers for Disease Control and Prevention
endorse the use of opioids, when appropriate, for the treatment of chronic pain, efficacy of long-term opioid use remains controversial.
the purpose of this review is not to minimize, or characterize, the risks of opioids, but rather to ensure that the debate over the risks and benefits of opioids is informed by an accurate assessment of their benefits.
Perhaps these researchers noticed what I did: recent studies of opioids only look at negative effects without ever mentioning that these drugs were given to control patients’ severe pain. (see Opioids Blamed for Side-Effects of Chronic Pain)
The present meta-analysis demonstrated the “effectiveness” of opioids since a majority of patients (63%) demonstrated a clinically meaningful response.
The pharmacological efficacy of opioids for the treatment of chronic pain was evidenced by statistically significant differences between study drug and placebo in change in pain score from randomization to week 12 and in response rates.
It is worth noting that
- AE [adverse events] rates in the double-blind periods were similar between study drug and placebo, with
- dropouts due to AEs being higher in the drug group while
- dropouts due to loss of efficacy were higher in the placebo group
It is worth noting that the efficacy of opioids is at least as large as that of any other treatment for chronic pain.
While the effectiveness of existing treatments for chronic pain leaves plenty of room for improvement, and considering that only a small minority of patients do not experience clinically meaningful treatment responses,
discarding entirely all analgesics approved for chronic pain contradicts numerous
- treatment guidelines,
- international treatment guidelines,
- widespread patient experience, and
- the FDA approval process.
These authors, as well as others, defined a 12-week treatment period as “short-term.”
While 3 months is indeed short in comparison to the years patients may use opioid treatment for chronic pain, 3-month treatment periods are considered the regulatory standard for assessing long-term efficacy of a treatment in placebo-controlled clinical trials of chronic conditions.
Indeed, the efficacy of all major drug and non-drug therapies for chronic pain is based on a similar body of evidence (ie, the number of studies and duration of those studies are similar for all chronic pain treatments).
Thus, the body of evidence for the efficacy of opioids is similar in terms of duration of studies to that for other approved classes of analgesics