How to control excess salivary flow in a patient with Parkinson's disease?

Hello doctor,

My mother has been a Parkinson's patient for ten years. For the past two years, she has been taking tablet Ropark 1 mg twice daily and tablet Syndopa 250 mg thrice daily. For the past year, she has been producing a lot of saliva and has difficulty swallowing and closing her mouth properly. This causes the saliva to leak all the time. Her eyes are lively now when compared to two years back. She has difficulty talking and swallowing. However, her memory and alertness are as good as for a 40-year-old, even though she is 77. She does not have diabetes and does not have cholesterol issues. However, her limbs are weak and not stiff enough. Can medications reduce her saliva flow?

Kindly advise.