The guidelines state that methylphenidate is safe for children over the age of six, but that health professionals should monitor patients for cardiovascular and psychiatric problems before and during treatment.
Monitoring should include assessment of BP, height and weight, pulse and symptoms suggestive of heart failure, which should prompt specialist cardiac evaluation.
Patients should be watched for changes in appetite and onset or worsening of psychiatric symptoms, the MHRA said.
Treatment should be interrupted annually to determine whether it should continue, the guidelines say. The advice follows a review of the drug's safety by the European Medicines Agency last year.
The MHRA has also said that patient information leaflets for methylphenidate products are being updated.
The new leaflets will include a tear-off section for children and adolescents taking the medication, written in a style designed to appeal to young people with ADHD.