Researchers from the Southeast Louisiana Veterans Health Care System and Tulane University have created a new painkiller that is just as strong as morphine, and is not likely to be addictive, according to a new study published in the journal Neuropharmacology.
In the study, researchers used rats to compare several variants of the neurochemical endomorphin to morphine, and measured their overall effectiveness and side effects. The endomorphin variants target the same pain-relieving opioid receptors as morphine.
Opioids are used effectively to treat many acute and chronic pain conditions, but they can be addictive and cause potentially fatal respiratory depression.
“These side effects were absent or reduced with the new drug,” said lead investigator James Zadina, VA senior research career scientist and professor of medicine, pharmacology and neuroscience at Tulane University School of Medicine. “It’s unprecedented for a peptide to deliver such powerful pain relief with so few side effects,” he added.
Researchers found that the new endomorphin drug produced longer pain relief and did so without substantially slowing breathing in rats. The rats who were given a similar dosage of morphine showed significant respiratory depression. When comparing motor function between the two groups, the rats taking the morphine had significant motor impairment, while the rats taking the new drug did not.
The researchers also led experiments to determine if the new drug was addictive. They observed that the rats who were given morphine spent more time in a compartment with morphine, while rats given the new drug did not spend more time in the compartment with the new drug. In another experiment, rats could press a bar and receive an infusion of either drug, and the rats only increased their efforts to receive morphine, versus the new drug.
Researchers hope to begin human clinical trials of the new drug within the next two years.