24-hour ambulatory blood pressure monitoring in male children receiving stimulant therapy.

OBJECTIVE: To determine whether cardiac indices are altered as assessed by 24-hour ambulatory blood pressure monitoring (ABPM) in male children receiving either chronic methylphenidate or dextroamphetamine/levoamphetamine (Adderall) therapy.

METHODS: Boys 7-11 years old who were receiving methylphenidate or Adderall for a minimum of 2 months were asked to participate. Subjects wore ambulatory blood pressure monitors for 24-hour periods both off and on stimulant therapy.

RESULTS: Subjects (n = 17; 8 methylphenidate, 9 Adderall) were well matched. Systolic blood pressure (SBP), diastolic blood pressure (DBP), and heart rate differed between off and on stimulant therapy (p < 0.05). DBP load calculated from ABPM reference data was increased significantly (9.0% +/- 5.6% on and 4.8% +/- 4.5% off therapy; p < 0.05) while subjects were taking Adderall. There was a trend toward a greater elevation in blood pressure load during awake hours and a more pronounced decrease during the asleep hours for periods on compared with off-stimulant therapy. This trend resulted in significant (p < 0.05) nocturnal dipping on-stimulant phases compared with off-stimulant therapy for both SBP and DBP (Adderall) and SBP (methylphenidate). Two subjects (1 Adderall, 1 methylphenidate) met the criteria to be considered hypertensive based both on mean awake and 24-hour blood pressure load assessments during their on-treatment period. One additional subject receiving Adderall therapy met the criteria to be considered hypertensive based on blood pressure load criteria while off therapy only. Positive correlation coefficients (p < 0.05) were found when comparing stimulant dose (mg/kg) with the percent change of mean SBP, DBP, and heart rate between off and on therapy (r = 0.56, 0.61, and 0.58, respectively).

CONCLUSIONS: These preliminary data suggest that blood pressure and heart rate appear to be altered in male patients while receiving stimulant therapy for attention-deficit hyperactivity disorder. Blood pressure and heart rate screening and monitoring during stimulant therapy to determine whether alterations become clinically significant is encouraged.