Morphine Can Prolong and Worsen Pain
Morphine, which is often doctors’ first choice to dull patients’ severe pain, can surprisingly have the opposite effect — prolonging and worsening pain.
That’s the latest word from a new study by American and Australian researchers, reported in the Proceedings of the National Academy of Sciences.
“[Morphine] works really well to begin with but we’re just now starting to understand some of the negative consequences,” notes Dr. Peter Grace, a pharmacologist who led the study and divides his time between the University of Colorado at Boulder and Australia’s University of Adelaide.
Co-researcher Dr. Linda Watkins, of the University of Colorado at Boulder, explains the use of morphine works on so-called “glial cells” that provide support and protection for neurons in the body’s nervous system. But she says the new research shows the drug can make “glial cells explode into action, making pain neurons go wild.”
According to Grace, the study’ findings relate to nerve pain such as sciatica and shingles. More research is needed, he adds, to determine whether opioid treatment of conditions such as lower back pain and fibromyalgia can trigger similar responses.
He considers it inadvisable to stop using opioids altogether but believes non-opioid alternatives such as pregabalin and amitriptyline should be considered first.
Amitriptyline is marketed under various brand names including Elavil. Brand names of pregabalin include Lyrica.
“What we’ve found is that opioid painkillers activate spinal immune cells, causing a further inflammatory response,” Grace reports. “The pain is effectively transitioned to a chronic state, making the pain itself more severe and longer lasting.”
He says the study findings are of concern because of the huge number of opioid prescriptions being written for patients each year.
“Our results add weight to the growing body of science suggesting that treatment with opioids such as morphine may in fact be a contributor to people’s chronic pain,” he notes.
A newly-developed technology called DREADD (Designer Receptor Exclusively Activated by Designer Drugs) enabled the researchers to isolate spinal immune cells and prove their involvement in responses to opioid use.
But there is some good news. Grace and his team managed to block the two main receptors implicated in chronic pain. In doing so, “we’re preventing the immune response from kicking in, enabling the pain-killing benefits of morphine to be delivered without resulting in further chronic pain.” What’s more, he adds, new drugs are in the pipeline that could replace morphine.
“If clinical trials of those drugs is successful, it could be another five years or so before patients are able to benefit from them,” he says.
“I hope this study will prompt clinical researchers to explore the long-term effects of opioids. The effects of opioids — good or bad — have not been evaluated beyond a year.
He adds that his team now plans to evaluate the long-term risks and benefits of other painkillers, such as oxycodone and fentanyl next, to see if these opioids have the same effect as morphine.
“A major part of our research is to identify drugs that can be given with opioids to suppress side effects (such as tolerance, pain and addiction) but keep the pain relief,” he says. “We’re also trying to develop new and better drugs for the treatment of chronic pain.”
By Chris Pritchard
Reprinted for educational purposes only. Reproduced from © 2016 NewsmaxHealth. Tuesday, 20 Sep 2016 03:32 PM