New opioid as effective as morphine but without the side effects

Scientists believe they may have found a new form of non-addictive painkiller that is as effective as morphine but without the potentially lethal side effects.

Morphine, which is derived from the opium poppy, works by acting on a receptor in the brain that reduces pain, but it also affects a different receptor that can lead to fatal breathing problems in the event of an overdose.

In a new study published in the journal Nature, a team of researchers from the US reveal how they deciphered the atomic structure of the "morphine receptor" in the brain to create a drug compound that blocks pain just as well as morphine, but without the harmful side effects that can lead to patient death.

Goal to alleviate pain without dangerous side effects

The team discovered the drug, which is called PZM2, after evaluating some three million different compounds. They hope that it could help to solve the problem of how to alleviate pain without the dangerous side effects associated with opioids.

In the mice studies, PZM21 did not appear to affect breathing and the painkilling effect of PZM21 lasted for up to three hours, “substantially longer” than the maximum dose of morphine. Furthermore, experiments revealed PZM21 did not stimulate the dopamine pathways in the brain, which are reward systems known to fuel addiction. The mice did not appear motivated to seek out the drug or show signs of addiction. 

Co-author Professor Brian Shoichet, from the School of Pharmacy at the University of California in San Francisco (UCSF) said: “Morphine transformed medicine. There are so many medical procedures we can do now because we know we can control the pain afterwards. But it's obviously dangerous too.

“People have been searching for a safer replacement for standard opioids for decades," he adds.


Cerebrospinal fluid. The fluid surrounding the brain and spinal cord. Full medical glossary
A type of neurotransmitter - chemicals that help the communication between nerve cells (neurons). Full medical glossary
One of the three main food constituents (with carbohydrate and protein), and the main form in which energy is stored in the body. Full medical glossary
A substance obtained from the unripe seed pods of the poppy plant. It can provide pain relief and also causes sleepiness and euphoria. Full medical glossary