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In people with chronic noncancer pain, opioids reduce pain by a small amount

Busse JW, Wang L, Kamaleldin M, et al. Opioids for Chronic Noncancer Pain: A Systematic Review and Meta-analysis. JAMA. 2018;320:2448-60.

Review question

In people with chronic noncancer pain, do opioids relieve pain?


Chronic (long-term) pain that is unrelated to cancer is common. It includes neuropathic pain (pain caused by damage to the nervous system), fibromyalgia, arthritis-related pain, and other types of noncancer pain.

Opioids are a class of pain-relieving drugs. They can also be dangerous because they are addictive, and by slowing breathing and heart rates, they can also cause death. This review looked at whether a specific class of drugs, opioids, can relieve chronic noncancer pain.

How the review was done

The researchers did a systematic review of studies available up to April 2018. They found 80 randomized controlled trials (RCTs) evaluating opioids. The RCTs included more than 20,000 people with an average age of about 58 years.

The key features of the RCTs were:

  • patients had osteoarthritis, rheumatoid arthritis, post-traumatic pain, post-traumatic neuralgia, painful diabetic neuropathy, postherpetic neuralgia, fibromyalgia, painful polyneuropathy, low back pain, phantom limb pain, chronic neck pain, or lumbar radiculopathy;
  • opioids included codeine, dihydrocodeine, fentanyl, hydrocodone, hydromorphone, meperidine, morphine, oxycodone, oxymorphone, tapentadol, and tramadol;
  • opioids were compared with placebo; and
  • people were followed for an average of 60 days.


What the researchers found

The evidence comparing opioids with placebo was of high quality.

Compared with placebo, opioids:

  • reduced pain severity by about 0.7 points out of a possible 10 points;
  • improved physical functioning by about 2 points out of a possible 100 points;
  • improved social functioning by about 1.6 points out of a possible 100 points;
  • improved sleep quality by about 3.4 points out of a possible 100 points;
  • did not improve emotional functioning; and
  • increased vomiting, constipation, drowsiness and other adverse events.

The improvements were very small and would not be noticeable by most people.


In people with chronic noncancer pain, opioids reduce pain by a small amount that would not be noticeable by most people.

Opioids vs placebo in people with chronic noncancer pain


Number of studies (and people)

Effect of opioids

Pain severity (after 3 to 6 months)

42 studies (16,617 people)

On a scale of 0 to 10, people reported a 0.7-point reduction in pain (could be as little as 0.6 and as many as 0.8 points).*

Physical functioning (after 1 to 6 months)

51 studies (15,574 people)

On a scale of 0 to 100, people’s physical functioning was about 2 points better (could be as little as 1.4 and as many as 2.7 points).*

Social functioning (after 1 to 4 months)

29 studies (7,623 people)

On a scale of 0 to 100, people’s social functioning was about 1.6 points better (could be as little as 0.5 or as many as 2.7 points).*

Sleep quality (after 3 to 6 months)

15 studies (6,585 people)

On a scale of 0 to 100, people slept about 3.4 points better (could be as little as 1.6 or as many as 5.3 points).*

Emotional functioning (after 1 to 4 months)

23 studies (8,962 people)

There was no evidence that people’s emotional functioning was better or worse with opioids.


33 studies (11,268 people)

About 7 more people out of 100 had vomiting (from as few as 5 to as many as 9 people).

*Although the opioid and placebo groups differed, the differences were not large enough for most individual patients to consider them important.

Related Topics


nerve pain
A harmless, inactive, and simulated treatment.
Randomized controlled trials
Studies where people are assigned to one of the treatments purely by chance.
Systematic review
A comprehensive evaluation of the available research evidence on a particular topic.

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