Frequency and individual severity of arterial blood pressure changes in children and adolescents with attention-deficit/hyperactivity disorder treated with methylphenidate hydrochloride: a prospective non-interventional study.

Background: Attention-deficit/hyperactivity disorder (ADHD) is a common behavioural disorder in childhood. The psychostimulant methylphenidate hydrochloride (MPH) is one of the major pharmacological options for ADHD. MPH is known to result, on average, in a small increase in arterial blood pressure (BP). However, there are few clinical data regarding the influences of MPH on BP among children and adolescents with ADHD. According to the European Union-wide standardised patient information sheet for MPH, BP changes >10 mm Hg compared with baseline values are 'common' (ie, ≥1% to <10%) in children and adolescents with ADHD during MPH therapy.

Aim: To investigate the frequency and individual severity of BP changes in children and adolescents with ADHD during the first 6 months of new MPH therapy.

Methods: In this study, 44 (77% male) children and adolescents (mean age (SD) 9.13 (1.86) years) with a diagnosis of ADHD according to the International Classification of Diseases, tenth revision, underwent ambulatory BP monitoring before and during the first 6 months of routine MPH therapy. Exclusion criteria were pre-existing MPH therapy and other medications that potentially influence BP or interfere with MPH. The non-interventional study was conducted prospectively at 10 paediatric cardiology centres in Germany and Austria.

Results: After beginning MPH therapy, 34% of participants (99% CI 15.52% to 52.66%) had BP increases/decreases >10 mm Hg. The mean changes in systolic BP and diastolic BP were 0.87 mm Hg (95% CI -1.75 mm Hg to 3.48 mm Hg) and 1.96 mm Hg (95% CI 0.21 mm Hg to 3.7 mm Hg), respectively. The proportion of participants with initial prehypertension/hypertension was 54.55%.

Conclusions: In our sample with a high baseline rate of prehypertension/hypertension, BP changes >10 mm Hg during MPH therapy were more frequent than those indicated by the patient information sheet. Moreover, individual BP changes, including increases and decreases >10 mm Hg, resulted in a small average BP increase in the sample, thus reflecting neither the severity nor the direction of individual BP changes. Therefore, the frequency and, due to the common use of the arithmetic mean, the individual severity of BP changes during MPH therapy may be underestimated. Further studies without averaging and with larger samples including patients in primary care settings are warranted.