I Have MSA - Multiple System Atrophy. The Treatment I'm

I have MSA - Multiple System Atrophy. The treatment I'm currently taking is 3 Sinemet every 3-4 hours, to control the stiffness and movement disorders. It does handle the pain associated pretty good, but when there is more pain than I can handle I take an nsaid or ibuprofen. I take some night time drugs, I take all together with some melatonin and ibuprofen, to help handle some muscle spasms, etc. I would like to understand the drug interactions that are possible with the Sinemet and the other drugs. The night drugs I take are: oxybutynin, Baclofen, & Flourinef. I also take an allergy pill at night, usually a Benadryl type. I try to space that one out 1 1/2 hours from the Sinemet as I've heard there is a possible reaction with that one.please advise as to the possible drug reactions and what could be their affect?