If you want to bring new drugs onto the market, it is necessary to demonstrate effectiveness and tolerability in clinical studies. Especially in the case of neurodegenerative diseases such as Parkinson's, with a sometimes very slow course, this can drag on for many years.

A tried and tested means of shortening this arduous path is to check drugs that have already been approved for unknown mechanisms of action.

It appears that such a new mechanism of action has been found in an ordinary cough syrup drug.

Ambroxol, discovered over 50 years ago and used as a medicine for coughs and respiratory diseases, appears to be effective in treating Parkinson's disease, according to a recent clinical study.

In January 2020, a team of researchers led by University College London (UCL) reported on a small phase II clinical study that indicated that ambroxol is safe and well tolerated in patients with Parkinson's disease and that a so-called neuroprotective effect can be expected .

Previous experiments with human cells and animal models suggest that ambroxol can help increase cell-protecting GCase proteins while lowering harmful alpha-synuclein levels.

"By increasing GCase levels, ambroxol allows cells to remove waste, which ideally keeps cells healthy longer and could slow the progression of Parkinson's disease," says UCL lead researcher and neurologist Tony Schapira.

And his colleague Stott adds: "If further studies show that ambroxol can improve the health and function of cells, it may lead to a slower progression of the disease in Parkinson's patients."

We're not there yet, and the results of this study need to be replicated in much larger tests, but the evidence so far is very promising, according to the researchers.

The next step, led by Schapira, is to determine the optimal dose of the drug.