How Much Sinemet 25-100 Is Really Necessary For My Mother

How much Sinemet 25-100 is really necessary for my Mother who is 76 years old with a creation kidney level of 1.6 (which is good for her) She was on temporary Dialysis before because of a overload of Medications such as Amantadine, Macrobid, Comtan & Prolia. I feel one tablet in the morning is enough. After her second dose which is a half tab at 1pm she gets sleepy and irritable. Just wanted to know how the Kidneys processed Sinemet with a creation level at 1.6

Thanks,

Lou (Son & Caregiver)