New painkiller as strong as morphine but not addictive
According to a new study in the journal Neuropharmacology, researchers at Tulane University and Southeast Louisiana Veterans Health Care System have developed a painkiller that is as strong as morphine but isn’t likely to be addictive and with fewer side effects.Using rats, scientists compared several engineered variants of the neurochemical endomorphin, which is found naturally in the body, to morphine to measure their effectiveness and side effects. The peptide-based drugs target the same pain-relieving opioid receptor as morphine.”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.”In the study, the new endomorphin drug produced longer pain relief without substantially slowing breathing in rats; a similarly potent dosage of morphine produced significant respiratory depression.
Impairment of motor coordination, which can be of particular importance to older adults, was significant after morphine but not with the endomorphin drug.The new drug produced far less tolerance than morphine and did not produce spinal glial cell activation, an inflammatory effect of morphine known to contribute to tolerance.Scientists conducted several experiments to test whether the drug would be addictive. One showed that although rats would spend more time in a compartment where they had received morphine, the new drug did not affect this behavior. Another test showed that when the press of a bar produced an infusion of drug, the rats only increased efforts to obtain morphine and not the new drug. The tests are predictive of human drug abuse, Zadina said.In addition, endomorphin did not result in spinal glial cell activation, an established effect of morphine that is known to help build up tolerance of the drug and in turn abuse or risk of overdose.Opiates have brought pain relief to people for centuries, but not without consequences. Motor impairment and respiratory depression are a couple of potential side effects and the risk of addiction remains the biggest problem. Opium based drugs are the leading treatments for severe and chronic pain, but they can be highly addictive.Patients also build up tolerance over time, increasing the risk for abuse and overdose.
The researchers are hopeful of commencing human clinical trials within the next two years.This latest study contradicts what happened just a week ago when a Californian company recalled all lots of a cough syrup product because it contains the opioid drug morphine.The product is promoted for the temporary relief of cough due to cold, minor throat and bronchial irritations.The Licorice Coughing Liquid product in 100ml bottles was said to contain compound camphor which includes opioids, said the agency in a recall notice. While compound camphor is listed on the label its ingredients including the opioid are not. Consumers using this product may not be aware they are ingesting morphine, noted the FDA and were at risk of life-threatening respiratory depression and death. It was also said that patients who are hypersensitive to morphine could suffer severe allergic reactions, and young children with a respiratory illness are vulnerable to respiratory depression from opioids and should not be exposed to morphine.