As the opioid epidemic rages on across the country, Indiana researchers are among those rethinking pain management.
But non-opioid medication has fallen short for those with chronic pain.
When you’re hurt, your nervous system sends a signal to your brain and you feel pain. Most pain medications mask the pain by blocking the receptors that cause you to feel it.
According to Richard van Rijn – a Purdue University medicinal chemist and molecular pharmacologist – the right type of medication depends on the type of pain. He says for chronic pain, it’s hard to find effective medication.
“In a surgical setting, we really rely on these opioids and they are very effective,” van Rijn says. “But when a pain persists for a long time – lower back pain, migraines, you name it – a lot of different things occur in your body that actually make these opioids not very effective to treat chronic pain.”
And last year, the Centers for Disease Control and Prevention recommended scaling back opioid prescriptions for those who deal with chronic pain.
Because of long-held misconceptions about the addictive nature of opioids, van Rijn says the medical and research communities weren’t actively looking for new options.
“Patients starting to overdose and die left and right is really when it becomes in the public’s radar,” he says. “And then, we’re scrambling to catch up. And you’ll find that we’re behind the curve.”
Another problem is the range of opioid-based drugs now available – including illegally. In 2010, Purdue Pharma – the makers of OxyContin, with no relation to Purdue University –released a physical reformulation of the drug that made it harder for users to break up a pill into powder.
But researchers at Notre Dame and Boston University found when that happened, there was a rise in deaths linked to heroin.
“Making one thing harder to abuse doesn’t mean that we’re going to stop abuse overall. It just means people might switch to something else,” Notre Dame Professor and study co-author Ethan Lieber says. “So, if you want to think of reformulations as like what we want to do, you might need to sort of reformulate…everything.”
Lieber says researchers need to think more about what can be substituted for prescription opioids.
“You would think that’s going to reduce the amount of abuse that happens on that drug,” Lieber says. “But the problem in this situation was that you had heroin available and heroin was actually much cheaper than OxyContin.”
In a Purdue University lab, a new kind of medication is being tested – one scientists can design to minimize adverse side effects while still providing the drug’s desired outcome.
Meridith Robins is one of the researchers. She says her team is focusing on alcohol abuse, but the principle can also be applied to drug addiction.
“This is a really hot topic with opioid research and also alcohol research right now -- this idea that you can have one target, one receptor, but opposing effects,” Robins says. “Of course, as humans, we’re interested in the effects that decrease addictive-like behavior.”
Here’s how it would work: the drug would be received by the brain, then take a path that enhances pain relief but avoid the path that leads to addiction or depression.
Robins says that property is found in about 40-percent of FDA-approved drugs.
“And now that we know about it, we can make new drugs and kind of put them on a heat map and see, okay, these are good toward this pathway, it means they might be better in the clinic – versus things that cause tolerance,” Robins says. “Or, more of something that we’d associate with a mood disorder and we can stay away from that stuff.”
Harvard Medical School Doctor Alice Flaherty says a better understanding of existing medicines could curb chronic pain more effectively than opiates currently do.
“Things like duloxetine – Cymbalta – and nortriptyline, that treat depression as well as pain,” Flaherty says. “They treat pain even if you’re not depressed and they get way underused by, say, an orthopedic surgeon who thinks it’s opiates or surgery or nothing.”
That’s a delicate conversation that doctors have to navigate with patients – one that may be getting easier, Flaherty says, after patients see research supporting the effectiveness of non-opioid treatment.
“That can be the turning point for people,” Flaherty says. “It’s really a wonderful and encouraging thing when you get somebody in pain off their chronic opiates and they start saying, ‘You know what, I feel better. I have more energy. My pain is actually better.’”
However, though researchers say they’re heartened by some of the ongoing studies, they agree the nation’s addiction to opioids – and the overdoses caused by it – are likely to linger at least a few more years.