Concerta input

My daughter (7) has been on Concerta for about 6 months. First half of that time was wonderful. Rave reviews from school, even i noticed she and I were arguing a lot less. Summer time was ehhh but chalked it up to staying up late, lack of routine etc. However I noticed her starting to be just more mean, verbally. Saying nasty comments to her sisters (they are all older teenagers), to me, other family members. And now school has started for the year, has been in 3 weeks, and already I'm getting calls from the teacher about her behavior. It made me sad because I had so much hope that she wouldn't struggle all thru second grade the way she did most of 1st. Has anyone else seen side effects like the shitty miserable mouthiness? We have an appointment at her pediatrician and obviously will let him know what's been going on but I'm looking for some parental experiences.

Thanks.