My 10 yr old had 4 days of biphentin 40 mg. Its like Concerta, available in Canada--its methylphenidate. All 4 days he had muscle twitches in his thighs. Now, almost 3 days after stopping, he still has the twitches and they seem to be getting worse but may actually be the same. They come and go and you can actually see them.

Does anyone know how long this will last? Doc says it'll go away but I'm worried. I've been combing the web and cannot find info on how long this will last after stopping, although it is a know side-effect.

He also had stomach aches and did not eat during the day.