As an adult, Concerta lasts 8 hours for me. Methylphenidate instant release lasts 2 1/2 – 3 hours. I’ve found a benefit from taking second smaller concerta dose, but timing is important. Have tried instant release in afternoon, but that seems to overshoot and then wear off quick. I’m experimenting with combining Concerta and Aptensio. Aptensio works much quicker than Concerta, so it’s a lot easier to notice the effect. Concerta takes about three hours to work for me, but it’s steady for several hours. Dosing is constant battle between doctor, insurance, and pharmacy. FDA guidelines should take into account how long patient needs the actual effect of the medication. As a parents of ADHD kids who also has ADHD, I need 16 hours. ADHD is worse as an adult parent, so absolutely do not skip having your child learn behavioral modifications along with medication. Can I drive while listening to music, having a stirring conversation with my wife, while my kids are arguing in the back seat, and not miss the turn. Absolutely not, but while medicated I can calmly say, one second I need to pay attention to where I’m going. Usually I wouldn’t distract myself by answering a forum, but I’m having a bathroom remodeling. Today is demolition day. So while I am medicated, I can’t focus with the banging so my ADHD sends me to instant gratification of screens.