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PEOPLE with Parkinson’s disease who rely on injections to fight off severe symptoms might one day be able to take a pill instead.

In the later stages of the disease, sufferers can go through debilitating periods when their bodies freeze into position, even if they are taking l-dopa or other drugs for their condition. Apomorphine, a dopamine mimic, is often used as a quick fix for these problems. But apomorphine has to be injected, which is awkward and painful. If taken as a pill, it flushes straight out of the body.

So Håkan Wikström’s group at the University of Groningen in the Netherlands went looking for a similar drug that could be swallowed. They hit on a compound that is converted to a dopamine mimic like apomorphine after digestion in rats. If this drug works as well in humans as it does in rats, it could be an alternative to apomorphine or l-dopa, they say in a forthcoming issue of the Journal of Medicinal Chemistry.

Big pharmaceutical companies would probably never have found this compound, says team member Durk Dijkstra. That’s because the pill itself doesn’t have an effect on cells’ receptors for dopamine when tested in the lab. It’s only converted into an active form inside the body. But most companies initially screen potential drugs in the test tube, and try only the active ones in animals. “They would have missed this compound,” says Dijkstra. “That’s surprising, and unfortunate.”

Jonathan Brotchie of the Parkinson’s Disease Society in London says the drug will be great if it acts as quickly as injected apomorphine. But he worries it might have strong side effects.