A French pharmacoepidemiological study characterized different patterns of incident use of methylphenidate in children and adults, finding long-term use with few co-medications in the former group, and higher frequency of use for a variety of indications, including possible misuse/abuse in the 25- to 49-year-old age group, as well as more co-prescriptions in the latter. The report was published in the British Journal of Clinical Pharmacology.
Methylphenidate is often prescribed for attention-deficit/hyperactivity disorder, but skyrocketing use globally has raised concerns about its long-term safety and efficacy, as well as questions about how different age groups are using the medication. The researchers sought to analyze and describe variations in age-related usage patterns in southern France.
A retrospective observational cohort study examined methylphenidate prescriptions and use between 2010 and 2013 in more than 4 million French residents using data from a national drug database. Patients were divided into 6 age groups (children age 1-5, 6-11, and 12-17; adults age 18-24, 25-49, >50) and assessed for total quantities dispensed, doses prescribed, median treatment duration, methylphenidate retention rates, and concomitant medication use.
Initially, there were 3534 individuals (66% children) identified as incident users, which resulted in a 7% increase in the annual incidence rate between 2011 (27 per 100,000) and 2013 (29 per 100,000). More boys used methylphenidate (2:1 ratio), but usage was evenly distributed among adults.
There were 2621 (75%) participants who filled at least 2 methylphenidate prescriptions and were included in the remaining analysis. Median treatment duration and methylphenidate retention rates both decreased with age, while average daily dosages increased with age, peaking in the 25- to 49-year-old group, which averaged 89.6 mg/d. In terms of concomitant medication use, individuals in the 25- to 49-year-old group also took more benzodiazepines (67%) and antidepressants (40%) than others, and individuals ≥50 took more antidepressants (58%) and antiparkinsonian medications (26%) than other individuals.
The elevated dosages and frequency in 25- to 49-year-olds, along with increased use of additional medications, raises concerns that methylphenidate was being used off-label and/or potentially abused by this group. The fact that 34% of new users were adults despite methylphenidate not generally being indicated in this age group supported such concerns.
Study limitations included unavailability of methylphenidate indication, illness severity, or socioeconomic patient information; not considering refills after 90 days for the treatment retention analysis; inability to determine reasons for treatment interruptions; non-inclusion of self-employed people; and uncertainty regarding the generalizability of results to the whole of France and beyond.
Future investigations should attempt to carefully explore these apparent patterns of use (and possible misuse), with an effort to determine the causes of such massive increases in methylphenidate prescriptions, particularly in the 25- to 49-year-old population. Clinician awareness of this issue is essential in order to continue providing effective treatment while attempting to reduce abuse of these prescription drugs.
Pauly V, Frauger E, Lepelley M, Mallaret M, Boucherie Q, Micallef J. Patterns and profiles of methylphenidate use in both children and adults [published online March 7, 2018]. Br J Clin Pharmacol. doi:10.1111/bcp.13544