Medical Design and Outsourcing

  • Home
  • Medical Device Business
    • Mergers & Acquisitions
    • Financial
    • Regulatory
  • Applications
    • Cardiovascular
    • Devices
    • Imaging
    • Implantables
    • Medical Equipment
    • Orthopedic
    • Surgical
  • Technologies
    • Supplies and Components Index
    • Contract Manufacturing
    • Components
    • Electronics
    • Extrusions
    • Materials
    • Motion Control
    • Prototyping
    • Pumps
    • Tubing
  • MedTech Resources
    • Medtech Events in 2025
    • The 2024 Medtech Big 100
    • Medical Device Handbook
    • MedTech 100 Index
    • Subscribe to Print Magazine
    • DeviceTalks
    • Digital Editions
    • eBooks
    • Educational Assets
    • Manufacturer Search
    • Podcasts
    • Print Subscription
    • Webinars / Digital Events
    • Whitepapers
    • Voices
    • Video
  • 2025 Leadership
    • 2024 Winners
    • 2023 Winners
    • 2022 Winners
    • 2021 Winners
  • Women in Medtech
  • Advertise
  • Subscribe

Post-Surgical Opioids Can, Paradoxically, Lead To Chronic Pain

April 19, 2018 By University of Colorado at Boulder

Giving opioids to animals to quell pain after surgery prolongs pain for more than three weeks and primes specialized immune cells in the spinal cord to be more reactive to pain, according to a new study by the University of Colorado Boulder.

The authors say the paradoxical findings, if replicated in humans, could have far-reaching implications for patient pain management and add a new wrinkle to the conversation about the national opioid epidemic.

“This indicates that there is another dark side of opiates that many people don’t suspect,” says senior author Linda Watkins, a professor in the Department of Psychology and Neuroscience. “It shows that trauma, including surgery, in combination with opiates can lead to chronic pain.”

For the study, Watkins and co-author Peter Grace, then an assistant research professor at CU Boulder, performed exploratory abdominal surgery, or laparotomy, on male rats. A similar procedure is done tens of thousands of times annually in the United States in humans, and opiates are routinely used after surgery.

“Opiates are really effective for acute pain relief. There is no drug that works better. But very little research has been done to look at what it is doing in the weeks to months after it’s withdrawn,” says Grace, now an assistant professor at MD Anderson Cancer Center in Houston.

(Image credit: Associated Press)

In one experiment, half the rats were given the equivalent of what would be a “moderate” dose of morphine in people for seven days postsurgery. Half were given a saline solution.

In another experiment, the rats were given morphine for eight days and then tapered off by day 10. In a third, the animals were given morphine until day 10 and then it was abruptly withdrawn.

Before and after the treatments, the researchers measured the animal’s sensitivity to touch as well as activity of genes that express inflammatory proteins in the spinal cord.

They found that rats given morphine experienced postoperative pain for more than three weeks longer. The longer they received morphine, the longer their pain lasted. And gradual tapering made no difference.

“This tells us that this is not a phenomenon related to opioid withdrawal, which we know can cause pain. Something else is going on here,” Grace says.

Watkins describes that something as a “one-two hit” on specialized immune system cells called glial cells in the central nervous system. The first hit, the surgery, stimulates what she calls the “not me, not right, not OK” receptor, Toll-like receptor 4 on the cells, igniting the release of a cascade of inflammatory proteins and “priming” them to be on guard for a second hit.

Morphine, which also stimulates that receptor, is the second hit.

“With that second hit, the primed glial cells respond faster, stronger and longer than before, creating a much more enduring state of inflammation and sometimes local tissue damage,” she says.

In a previous study, published in the Proceedings of the National Academy of Sciences in 2016, the researchers showed that just a few days of treatment with opiates to treat peripheral nerve pain, such as sciatica, could exacerbate and prolong pain for months in animals, in part by increasing expression of inflammatory genes.

A few small studies in humans have associated postsurgical opioid administration with chronic pain as much as one year later.

“An unusually high number of people end up with postoperative chronic pain. This new study lends insight into one explanation for that,” Watkins says.

The researchers, acknowledging that animal studies cannot directly translate to humans, are now calling for more clinical studies on opioids and chronic pain.

More than 50 million U.S. adults experience chronic pain, according to the National Institutes of Health.

Watkins is also studying novel compounds that could be given with opioids to mute the exaggerated immune response they are believed to trigger, as well as alternative painkillers, including cannabinoids, for pain.

“There is surely a dark side in terms of addiction when it comes to opioids, but this is a very different idea–that we think we are treating the pain with these drugs and we may actually be prolonging it,” she says.

Related Articles Read More >

This is a Zimmer Biomet marketing image of its Rosa robotic surgery system.
Zimmer Biomet seeks a ZBEdge for its Rosa robotic surgery
A photo of Capstan Medical's mitral valve implant, which uses nitinol.
Capstan Medical’s R&D head discusses the heart valve and robotics startup’s tech, engineering challenges and solutions, advice for others in medtech and how to join his team
An illustration of a neurosurgeon using a robotic endoscope to remove a brain tumor.
MDO Nitinol Innovation Special Report
A photo of Highridge Medical CEO Rebecca Whitney.
Highridge Medical is betting on this spine tech
“mdo
EXPAND YOUR KNOWLEDGE AND STAY CONNECTED
Get the latest medical device business news, application and technology trends.

DeviceTalks Weekly

See More >

MDO Digital Edition

Digital Edition

Subscribe to Medical Design & Outsourcing. Bookmark, share and interact with the leading medical design engineering magazine today.

MEDTECH 100 INDEX

Medtech 100 logo
Market Summary > Current Price
The MedTech 100 is a financial index calculated using the BIG100 companies covered in Medical Design and Outsourcing.
DeviceTalks

DeviceTalks is a conversation among medical technology leaders. It's events, podcasts, webinars and one-on-one exchanges of ideas & insights.

DeviceTalks

New MedTech Resource

Medical Tubing

MassDevice

Mass Device

The Medical Device Business Journal. MassDevice is the leading medical device news business journal telling the stories of the devices that save lives.

Visit Website
MDO ad
Medical Design and Outsourcing
  • MassDevice
  • DeviceTalks
  • MedTech100 Index
  • Medical Tubing + Extrusion
  • Medical Design Sourcing
  • Drug Delivery Business News
  • Drug Discovery & Development
  • Pharmaceutical Processing World
  • R&D World
  • About Us/Contact
  • Advertise With Us
  • Subscribe to Print Magazine
  • Subscribe to our E-Newsletter
  • Listen to our Weekly Podcasts
  • Join our DeviceTalks Tuesdays Discussion

Copyright © 2025 WTWH Media, LLC. All Rights Reserved. The material on this site may not be reproduced, distributed, transmitted, cached or otherwise used, except with the prior written permission of WTWH Media LLC. Site Map | Privacy Policy | RSS

Search Medical Design & Outsourcing

  • Home
  • Medical Device Business
    • Mergers & Acquisitions
    • Financial
    • Regulatory
  • Applications
    • Cardiovascular
    • Devices
    • Imaging
    • Implantables
    • Medical Equipment
    • Orthopedic
    • Surgical
  • Technologies
    • Supplies and Components Index
    • Contract Manufacturing
    • Components
    • Electronics
    • Extrusions
    • Materials
    • Motion Control
    • Prototyping
    • Pumps
    • Tubing
  • MedTech Resources
    • Medtech Events in 2025
    • The 2024 Medtech Big 100
    • Medical Device Handbook
    • MedTech 100 Index
    • Subscribe to Print Magazine
    • DeviceTalks
    • Digital Editions
    • eBooks
    • Educational Assets
    • Manufacturer Search
    • Podcasts
    • Print Subscription
    • Webinars / Digital Events
    • Whitepapers
    • Voices
    • Video
  • 2025 Leadership
    • 2024 Winners
    • 2023 Winners
    • 2022 Winners
    • 2021 Winners
  • Women in Medtech
  • Advertise
  • Subscribe