Quirks and Quarks

For some people, opioids can actually make pain worse

Finding out why opioids make pain worse not better for some people could lead to the development of more effective, less-addictive medication.
Opioids can be extremely helpful to treat short-term pain. Taken long-term, the risks can increase in a variety of ways. (Canadian Press)

Scientists are learning how weaning off opioids like morphine or fentanyl can be even more complicated than they thought.

The narcotic painkillers are essential to dull the excrutiating pain that can follow things like surgery or cancer. 

When taken for more than a month, the medications risk causing more harm than good in a variety of ways.

Travis Rieder knows first hand. When he nearly lost his foot in a motorcycle accident in May 2015, Rieder was in agony. He needed opioids for pain from the both the crash and several surgeries to recover.

But two months after he starting taking the pain pills, he realized just how many he was consuming. Then, desperation sunk in.

When rats with a nerve injury were given morphine, they took twice as long to recover. (Wikimedia Commons)

Rieder says he was left to wean himself off the medication too quickly, without much guidance from his doctors.

He white-knuckled his way through physical dependence and withdrawal with the help of his wife and baby daughter.

I thought that I was broken beyond repair and I was never going to be normal again.- Travis Rieder

"Each time I dropped another dose, I was increasing the severity of the symptoms. I eventually stopped sleeping at all, I stopped eating at all and towards the end I got severely depressed and towards the end actually became suicidal because I thought that I was broken beyond repair and I was never going to be normal again," Rieder recalled. 

Rieder, a research scholar at the Berman Institute of Bioethics at Johns Hopkins in Baltimore, now wants opioid prescribers to be held accountable not only for unnecessary prescribing, but also to really help their patients to manage those prescriptions. For instance, he suggests they:

  • Prescribe as few opioids as possible for as short a time as possible.
  • Clearly tell patients that taking the medications in the long term puts them at high risk for developing biological dependence.
  • Have an "exit plan" to taper off opioids slowly, for instance with counselling supports.

Rieder worries that the severe withdrawal he experienced from tapering off too quickly can drive people back to the drugs. 

While withdrawal is one of the most difficult aspects of the prescription portion of the opioid crisis, scientists are learning more about other aspects.

When opiods actually worsen pain 

One is that opioids can actually increase sensitivity to pain.

Travis Rieder (Linked In)

In "opioid-induced hyperalgesia," painkillers taken in the long term can have exactly the opposite effect of what they are meant to do.

Neuroscientist Peter Grace is a professor at MD Anderson Cancer Center in Houston. He dove into the spinal cord of rats to learn why it happens for nerve injury.

By using animal models, Grace aims to better understand the underlining biology behind the increased pain sensitivity that can occur when opioids are taken long term.

The rats were treated with morphine for five days. 

Then the scientists gave both the injured rats and uninjured, control animals pokes in their hind paws.

Grace says he was surprised to find a doubling in recovery time. ​It took twice as long for the morphine-treated rats to recover from the pain sensitivity compared with the control rats.

"It was such a striking effect and we were dosing our rats with what's considered a moderate dose in people."

He suspects that the combination of nerve damage and morphine delivers a one-two punch to cells in the spinal cord called microglia.

Normally, microglia work to clean up damage in nerves. But after a nerve injury, the cells can become "angry," he says, and hyperalgesia may occur. The microglia spew excitory signals and keep firing for longer with a stronger signal than without the combination of nerve injury and opioids.

There haven't been long-term studies in humans reporting this type of hyperalgesia confirmed by doctors to tell how common the problem might be in patients, says Dr. Yoanna Skrobik, a professor of medicine at the University of Montreal and Queen's University in Kingston, Ont.

Skrobik isn't involved in the research. The critical care physician treats pain in patients in hospital.

Need for pain meds drops with music 

"I am a strong believer in co-analgesia," Skrobik says of her treatment approach. "In terms of the brain and peripheral nervous system, when you take Tylenol and you take Advil and you take morphine all of those pharmacological inteventions will [act] in different places and in different ways."

For instance, bone pain may respond to different medications than nerve-based pain, says Skrobik, a spokesperson for the Canadian Deprescribing Network that aims to reduce unnecessary and potentially harmful use of prescription medications. 

Skrobik adds that while nonpharmacological interventions such as relaxation techniques aren't likely to work well for acute, short-term pain, they can be extremely helpful for some types of chronic pain. 

"In the intensive care unit and in the post-operative unit, if you make people listen to music that they like, the amount of pain medication that they requires goes down dramatically."

It can also help if people keep detailed diaries of their pain symptoms, she suggests.