Safer opioid painkiller developed from scratch.

• Position: Addiction

An opioid drug candidate that blocks pain without triggering the dangerous side effects of current prescription painkillers has been developed by an international team of researchers, led by scientists at the University of California, San Francisco; Stanford (Calif.) University; University of North Carolina, Chapel Hill; and Germany's Friedrich-Alexander University Erlangen-Nurnberg. Their secret?--starting from scratch, with computational techniques that let them explore more than four trillion different chemical interactions.

In a study published in Nature, the researchers used the newly deciphered atomic structure of the brain's "morphine receptor" to custom engineer a novel drug candidate that blocked pain as effectively as morphine in experiments, but did not share the potentially deadly side effects typical of opioid drugs. In particular, the new drug did not interfere with breathing--the main cause of death in overdoses of prescription painkillers as well as street narcotics like heroin--or cause constipation, another common opioid side effect. The new drug also appears to sidestep the brain's...