For adults with narcolepsy, the total dosage of Ritalin per day is usually 20 mg to 30 mg (divided into two or three doses). Some people may need less Ritalin, while others may need as much as 60 mg per day.Author: Kristi Monson, Pharmd; Arthur Schoenstadt, MD. The usual dosage of Ritalin for an adult is 10 - 30 mg per day, but can be as high as 60 mg per day. The effects of this drug should last 8 - 12 hours, but may not be as pronounced during the last.
Dec 04, 2017 · For ADHD, the Adderall dosage for adults is between 5 to 40 mg a day in the immediate-release version. The Adderall dosage for adults is divided throughout the day, and doses of more than 40 mg a day are seen as rarely being any more effective than the 40 mg threshold.5/5(1). Adderall vs. Ritalin: What’s the Difference?