A common cough medicine may slow cognitive decline in people with Parkinson’s disease dementia, a clinical trial has revealed.
A 12-month study conducted by researchers at Lawson Research Institute found that Ambroxol helped stabilise psychiatric symptoms, improved cognitive function, and protected against brain damage in genetically at-risk participants.
Parkinson’s disease dementia (PDD) causes symptoms such as memory loss, confusion, hallucinations, and mood changes. Approximately 153,000 people in the UK live with Parkinson’s disease.
There is currently no cure for PDD, but patients can take medications called cholinesterase inhibitors to help manage symptoms.
“Our current treatments for Parkinson’s disease and dementia treat the symptoms, but do not change the underlying course of the disease,” Dr Stephen Pasternak, the lead author of the study, told The Standard.
“We hope that Ambroxol, a cough medicine available over the counter in most of the world, but not in the United States or Canada, will change the course of Parkinson’s disease dementia (and related diseases).”
Parkinson's dementia symptoms
- Difficulty focusing
- Difficulty making decisions
- Memory loss and forgetfulness
- Difficulty staying awake
- Disturbed sleep
- Visual hallucinations
- Delusions
- Changes in appetite
- Mood changes such as depression, anxiety and apathy
What did the study find?
The study, published in JAMA Neurology, involved 55 participants who had Parkinson’s disease dementia (PDD), monitoring their memory, psychiatric symptoms, and GFAP, a blood marker linked to brain damage.
It found that GFAP increased in the placebo group but stayed stable for participants taking Ambroxol.
As well as this, dementia symptoms worsened in the placebo group, but not for those on Ambroxol.
Participants also showed improved cognitive performance on Ambroxo.
“Individuals receiving placebo showed a clinically meaningful worsening in neuropsychiatric symptoms, whereas those receiving ambroxol remained stable,” the scientists wrote.
“Ambroxol was safe, well-tolerated, and demonstrated target engagement,” the researchers wrote. “However, the effect of ambroxol on cognition was not confirmed.”
How could Ambroxol impact Parkinson’s
Ambroxol boosts an enzyme called GCase, which clears away waste products that accumulate in brain cells.
The enzyme is often deficient in Parkinson’s patients, causing waste to build up in brain cells, including an unwanted protein called alpha-synuclein.
It’s thought that Ambroxol may help the body reduce this waste, preventing brain damage.
Ambroxol was first considered as a potential Parkinson's treatment in 2009.
In 2020, a trial funded by Cure Parkinson’s and its partners showed that Ambroxol could reach the part of the brain that boosted GCase and was safe for people with Parkinson’s.
“We hope that Ambroxol, or drugs like Ambroxol, will be able to prevent the onset of Parkinson's disease and dementia if it is given early enough,” Dr Stephen Pasternak told The Standard.
Pasternak is continuing to explore whether Ambroxol can help people suffering from Parkinson’s dementia, with plans to begin a follow-up clinical trial specifically focused on cognition later this year.
His team is currently trying to secure funding for a study focused on dementia alone. They are also working with an American company, Zywie Bio LLC, to examine analogues of Ambroxol that they hope will have better pharmacological properties.
"If a drug like Ambroxol can help, it could offer real hope and improve lives."
