I've been prescribed 100 mg methylphenidate per day in 3 doses for the last 15 years. My doctor is switching me to Adderal XR 20 mg instead. I tried this change yesterday and felt like I had not taken anything. I don't think I took enough Adderal XR. I'd like to know what would be the equivalent dose of Adderal XR after switching from 100 mg/day of immediate release methylphenidate. Thank you!