My son had a slightly elevated blood pressure for the years he took Concerta. It wasn’t so high that any physician was concerned and an EKG came back perfectly normal.
There is a blood pressure medication that is used to treat ADHD sometimes: Guanfacine (the long-acting version is Intuniv). If the Concerta is working really well for him, except the blood pressure issue, then adding guanfacine could resolve that and still have good treatment.
Here’s more on Guanfacine:
ADDitude Community Moderator, Parenting ADHD Coach, Podcaster & Author, Mom to teen w/ ADHD, LDs, and autism