All medications for ADHD last less than an entire day but different forms last different amounts of time. The body can get used to medicines that start out lasting through much of the day so that they no longer last as long. For some medicines increasing the morning dose will increase the duration. In other cases an additional dose of the same of a different medicine can be helpful to cover important times of day when better behavioral or attentional control. Making these adjustments is an important reason for regular follow up visits with your child's doctor. Be sure to fill out a Vanderbilt checklist when you have concerns over duration of medicine and get teachers to do this also to provide the objective feedback needed to determine if adjustments are needed.