Is Combination Of Arip MT And Ispiral Harmful For Child With ADHD?

Hi my 10 year old has ADHD. He has been on Arip MT.05 for the last one year. His doctor has recently started on Ispiral 10, which has the same salts as Ritalin, I m told. My worry is: a) Will the combination of the two cause him any health problems ? b) Now that the drugs are helping him a great deal, will he be required to use them for the rest of his student life ? I m a Communication professional who right now has given up my career in order to take care of my child. I m 47 yrs old,5 ft +, and have Hypo Thyroid. When I got pregnant I did not have to take my thyroid medication as miraculously there was no need. Please tell me ?