How old is your father?
I think age, how long on PD meds, and how many total meds can become a issue..
When my dad hit 80 we needed to assess his misc meds for what is actually helping vs negatives.. Our Dr was good about testing & stopping ones when we told her about issues..

Try our search tool and explore the PD sticky threads, so much info saved in those.. For search use symptom, med or other keyword for best results from past posts..

Many use miralax or such product to keep regular, as constipation is an issue and may block absorption of good things as well as slow the elimination of toxins..