There are two types of methylphenidate medications available in the United States, Ritalin LA and Metadate CD. Both medications are used to treat Attention Deficit Hyperactivity Disorder (ADHD), but they work in different ways.

Ritalin LA is a long-acting medication that is taken once a day. It releases methylphenidate slowly over time, which means that it lasts for up to eight hours. Metadate CD is a short-acting medication that is taken two or three times a day. It releases methylphenidate quickly, which means that it only lasts for four to six hours.

Both medications are equally effective at treating ADHD …