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Study:  Efficacy of opioids versus placebo in chronic pain: a systematic review and meta-analysis of enriched enrolment randomized withdrawal trials

opioid pain medications

Diana S Meske, Oluwadolapo D Lawal, Harrison Elder, Valerie Langberg, Florence Paillard, Nathaniel Katz

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5939920/

May 2018

Information courtesy of Kev James, Chronic Pain Patient Advocate. LinkedIn

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, the study authors performed a meta-analysis of published clinical trials for μ-opioid receptor agonists performed for US Food and Drug Administration approval.

The study authors searched the MEDLINE and Cochrane trial register for enriched enrolment 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.

The results were opioid efficacy was statistically significant versus placebo for pain intensity, the improvement in pain being greater than 50%.  There were minor benefits on physical function and no effect on mental function.

This study clearly concludes that opioids are effective for chronic pain for at least a period of 3 months, which is and appropriate time frame, given that opioids are often trialed for a period of three months to see if they are effective and if side effects are tolerable.  From the study:

This meta-analysis of FDA-required double-blind, randomized, placebo-controlled clinical trials of opioid analgesics for the treatment of chronic pain has shown that there is an ample evidence base supporting the efficacy of opioid analgesics for at least 3 months’ duration, a standard period for the evaluation of treatments for chronic pain and other chronic disorders

Limitations of the study include:

The study states that it “only included EERW studies, therefore only included results from patients who responded to opioids during the open-label titration phase….Perceived disadvantages to the EERW design include questions about the generalizability of both efficacy and AE data, challenges in comparing outcomes to standard prospective parallel treatment designs, and more complex interpretation.”

Another limitation is that most of the studies focused on chronic lower back pain

Additionally, the study did not evaluate adverse events, focusing purely on efficacy. Of course every medication needs to be weighed up, a risk/benefit balance considered. But previously doctors have refused to trial opioids, citing a lack of long-term efficacy. And if a medication is not effective, no risk is acceptable. This study disproves that idea, and in fact, shows that opioids ARE effective for three months and longer and are therefore a viable therapy for chronic pain.

Chronic pain patients who benefit from opioid therapy have known for many years that opioids ARE effective for their pain, and it is gratifying to see the science, the evidence, starting to catch up.

Hopefully, and most importantly, physicians will be reassured that opioids are effective long-term and re-prescribe opioids to those patients who have been brutally force-tapered on the unfounded idea that opioids are not effective for chronic pain.

2 thoughts on “Study:  Efficacy of opioids versus placebo in chronic pain: a systematic review and meta-analysis of enriched enrolment randomized withdrawal trials”

  1. While living in NZ l was prescribed DHC continus following a knee injury when total knee replacement was not available. I never needed the surgery but also pain caused by widespread osteoarthritis and fibromyalgia was vastly improved allowing me to join my sister and friend who were experienced bushwalkers to join them on their walks including steep hills and beach walks. The medication changed my life and I was trim, fit and strong. I took the medication for 9 years. The only side effect was a slight tendency to constipation, easily managed. I then returned to Australia where it was not available and no equivalent pain relief could be found. After 2 and a half years I reduced to an invalid with no quality of life, barely able to manage my household chores and shopping. Specialist fees, blood tests and alternative medications have cost me a fortune. In NZ the cost was $5 for 3 months supply.
    After 6 months I reached the safety net so no charge.
    Some doctors and pharmacists in Australia have left me humiliated for taking opiods which have never caused a problem.

    1. Thank you for sharing your story, Avis. Its very clear that without proper pain relief your quality of life has decreased dramatically. It makes no sense that you can’t access a medication that was so successful for you, allowed you to be fit and healthy, and gave you good quality of life – a more’normal’ life.

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