Short-term effects of lisdexamfetamine dimesylate on cardiovascular parameters in a 4-week clinical trial in adults with attention-deficit/ hyperactivity disorder

Objective: To evaluate the short-term impact of lisdexamfetamine dimesylate on cardiovascular parameters in adults with attention-deficit/ hyperactivity disorder (ADHD). Method: Medically healthy adults (18-55 years of age) with DSM-IV-TR-defined ADHD were randomly assigned to placebo or 30, 50, or 70 mg/d of lisdexamfetamine dimesylate for 4 weeks between May and November 2006. Electrocardiograms, systolic and diastolic blood pressure, and pulse were assessed pretreatment and weekly thereafter. Results: There were no significant differences for mean systolic or diastolic blood pressure in any lisdexamfetamine dimesylate dose group versus placebo. Changes in pulse from baseline to endpoint were 0.0, 2.8, 4.2, and 5.2 bpm in the placebo and lisdexamfetamine dimesylate 30, 50, and 70 mg/d groups, respectively (P < .05, all lisdexamfetamine dimesylate groups vs placebo). Post hoc pulse outliers (pulse ≥ 100 bpm; any 1 event) ranged from 3.3% to 8.5% of subjects in the lisdexamfetamine dimesylate groups, and no subjects in the placebo group were pulse outliers (P < .05 for lisdexamfetamine dimesylate 50 mg vs placebo only). There were no clinically meaningful electrocardiogram abnormalities. Overall, 8.3% (35/420; safety population) of subjects had treatment- emergent cardiovascular adverse events, and 1.7% (7/420) withdrew from the study because of cardiovascular complaints. Cardiovascular adverse events with lisdexamfetamine dimesylate in these medically healthy adults were generally mild to moderate in severity. Conclusions: Lisdexamfetamine dimesylate had limited short-term effects on heart rate, blood pressure, and electrocardiogram parameters that were of minimal clinical concern. These findings support the relative safety of lisdexamfetamine dimesylate. However, considering the potential of outliers, it is advisable to monitor cardiovascular parameters in stimulant-treated patients. Interpretation of these findings is limited to patients with no preexisting cardiac conditions who are taking their medication as prescribed. Trial Registration: clinicaltrials.gov Identifier: NCT00334880