I take the following medications, metformin, lisinopril, nuvigil, ritalin and prozac. The last three are for nacolepsy with cataplexy that I developed within the last year at age 67. I understand you might need to know the dosages. I will be seeing my doctor next week but in the meantime I just wanted to research a little online. Occasionally, my hands feel slightly jittery and I was wondering if one or a combination of all the meds would be causing this. When he prescribed the narcolepsy cocktail, my doctor suggested that I not take the ritalin every day so I take it about 5 times a week, depending if I m going out of the house for the day. I understand that I will not change my prescription without consulting my doctor first. I just wanted to know if any of these would cause mild jitteriness for lack of a better term or if I should try to see my doctor sooner. Let me add that I usually drink diet soda, one or two cans a day, but I am trying hard to drink more water instead. However, lately I haven t had diet soda in the house but I ve been drinking diet Snapple. I realize they are not good choices. I ve never felt invigorated after drinking cola and it never keeps me awake but I m wondering if the Snapple has more caffeine and that s what s affecting me. Of course, I can easily prove that theory but not drinking it. I don t drink coffee or tea and very seldom any alcoholic beverage. Thanks so much for your time.