2.2 Inclusion Criteria We included all subjects dispensed an ADHD or asthma medication between 1 February 2011 and 31 January 2012 who had data available for at least 4 months prior to the first dispensing (index date), and whose pharmacies consistently supplied data to the LRx database during the entire study period. Each subject was followed for 18 months from his/her
index date. A subject who was dispensed ADHD and asthma medications could be a member of both cohorts. 2.3 Prescription/Dispensing Data We included all ADHD medications whose ingredients were approved by the US FDA for the treatment of ADHD. These were the stimulants amphetamine, dexmethylphenidate, dextroamphetamine, lisdexamfetamine, methamphetamine, and methylphenidate, and the non-stimulants PFT�� ic50 atomoxetine, clonidine, and guanfacine. The asthma medications included were inhaled bronchodilators, inhaled steroids, inhaled steroid/long-acting β agonist combinations, and oral leukotriene inhibitors. Asthma medications were used as a comparator because they are Savolitinib concentration frequently used by a population with roughly similar
demographic characteristics as the population using ADHD medications [12], including a large VX-689 chemical structure representation of children and young adults, and are not believed to be widely abused or diverted [13]. Subjects who were not dispensed any ADHD medication during the 4 months before their index date were considered ‘naive’. The 4-month
period, rather than a shorter period, was adopted to decrease the risk of misclassifying as naïve a subject who was receiving an ADHD medication during the school year but took a planned break in its use during 3 or 4 months of vacation (i.e. took a ‘drug holiday’). 2.4 Outcome We assessed the number of subjects with overlapping dispensings of medications prescribed by different prescribers, and the number of prescribers and number of pharmacies involved in those dispensings, during the 18 months of follow-up. For subjects Niclosamide with more than one event of multiple overlapping filled prescriptions, we selected the one event with the maximum number of overlapping prescriptions. Note that a prescriber can write more than one prescription for a given individual, therefore the total number of pharmacies making dispensings for that individual may exceed the number of prescribers. An overlap occurred when two or more dispensings of medications prescribed by different prescribers were active on the same day (i.e. a medication was dispensed during the days’ supply of another dispensed medication). The overlapping dispensings could be for the same or different ADHD or asthma medications.