Medication interactions can occur with any prescription or over the counter medicine. In this case, I will not be able to tell for sure what our mother can or can't take because there are many different Parkinson's medicines with different interactions. However, there are some remedies that are fairly low risk that your mother could try. A cough can be a sign of a common cold or something more serious such as pneumonia
. When someone has other diseases to contend with it is always best to err on the side of caution when deciding whether to get something looked at. I suggest you call the physician that is caring for your mother's Parkinson's disease and get a list of over the counter medicines that could commonly be used to treat cough's and aches and pains and are safe to take with her current regimen. This way you will know that what she is taking is okay. In addition, I think you should schedule an appointment with your mother's primary care physician
to discuss the cough. You want to make sure she doesn't have anything more serious like pneumonia that would need antibiotic treatment. In the mean time, it is probably okay for your mother to use cough drops with menthol and honey to help control her coughing symptoms. I hope she feels better.