Patterns and predictors of medication compliance, diversion, and misuse in adult prescribed methylphenidate users.
ABSTRACT To examine patterns and predictors of medication compliance, diversion, and misuse in a sample of adults with prescriptions for the stimulant medication methylphenidate (MPH).
Sixty-six adults currently prescribed MPH (53% male) completed structured interviews and provided details regarding their medication and other substance use histories.
On average, participants reported using their medication as prescribed on 14.5 (SD 11.7) of the past 30 days; 44% admitted to diverting it and 29% admitted to inappropriate use. While analyses revealed that medication misuse, diversion, and level of compliance were interrelated and all associated with concurrent illicit substance use, each also had other distinct associations. Specifically, MPH misuse was associated with the use of illicit stimulants such as amphetamine and cocaine, diversion with age and age of MPH prescription, and compliance with participation in an attention deficit hyperactivity disorder (ADHD) support group. Regression analyses revealed that misuse and poor compliance were both best predicted by concurrent illicit substance use, while the model that best predicted diversion included age of first MPH prescription (younger) and MPH misuse.
Poor medication compliance, diversion, and misuse are relatively common and interrelated among adult MPH users. MPH prescriptions should be monitored closely in individuals with histories of illicit substance use.
Article: The diversion and misuse of pharmaceutical stimulants: what do we know and why should we care?[show abstract] [hide abstract]
ABSTRACT: To examine the literature pertaining to the diversion and misuse of pharmaceutical stimulants. Relevant literature was identified through comprehensive MEDLINE, EMBASE and PubMed searches. The evidence to date suggests that the prevalence of diversion and misuse of pharmaceutical stimulants varies across adolescent and young adult student populations, but is higher than that among the general population, with the highest prevalence found among adults with attention deficit-hyperactive disorder (ADHD) and users of other illicit drugs. Concerns that these practices have become more prevalent as a result of increased prescribing are not supported by large-scale population surveys. Information on trends in misuse in countries where there have been recent increases in prescription and consumption rates, however, is limited. Little is known about the frequency and chronicity of misuse, or the extent of associated harms, particularly among those populations, i.e. adolescents, young adult student populations, those with ADHD and illicit drug users, where abuse may be more likely to occur. Continued monitoring of the diversion and misuse of pharmaceutical stimulants is of major clinical importance. Despite recognition of the abuse liability of these medications, there is a paucity of data on the prevalence, patterns and harms of diversion and misuse among populations where problematic use and abuse may be most likely to occur (e.g. adolescents, young adults, illicit drug users). Comprehensive investigations of diversion and misuse among these populations should be a major research priority, as should the assessment of abuse and dependence criteria among those identified as regular users.Addiction 03/2012; 107(3):467-77. · 4.31 Impact Factor
Article: Predictors and impact of non-adherence in adults with attention-deficit/hyperactivity disorder receiving OROS methylphenidate: results from a randomized, placebo-controlled trial.[show abstract] [hide abstract]
ABSTRACT: BACKGROUND: Medication non-adherence has an important impact on treatment efficacy and healthcare burden across a range of conditions and therapeutic areas. The aim of this analysis was to determine predictors of non-adherence and impact of non-adherence on treatment response in adults with attention-deficit/hyperactivity disorder (ADHD). METHODS: Post-hoc analysis of a 13-week randomized, double-blind placebo-controlled study of OROS methylphenidate (MPH) 54 and 72 mg/day. Primary efficacy variable was the Conners' Adult ADHD Rating Scale -- Screening Version (CAARS:O-SV). Daily adherence was calculated as average daily adherence (100 x capsules taken/2), with overall adherence calculated as the average daily adherence. Predictors of adherence were assessed using mixed-effects logistic regression. Descriptive statistics were generated for change in CAARS:O-SV score for adherent (> 95% adherence) and non-adherent subjects. Predictors of change were analyzed using a mixed model. RESULTS: Subjects were allocated to OROS MPH (54 mg, n = 87; 72 mg, n = 92) or placebo (n = 97). Mean adherence was 92.6% and 93.3% (OROS MPH 54 and 72 mg/day, respectively), versus 97.5% (placebo). Adherence was higher and less variable in completers. Factors significantly associated with non-adherence included female sex, shorter time since ADHD diagnosis, higher education level (completion of university) and score on the Drug Use Screening Inventory psychiatric disorders subscale. Improvements from baseline in CAARS:O-SV score were numerically greater in subjects defined as adherent than in those who were non-adherent. Significant predictors of CAARS:O-SV change in patients who completed the study included percentage adherence up to the point of assessment (p < 0.0001), baseline score (p < 0.0001) and family history of ADHD (p = 0.0003). CONCLUSION: The results of this analysis suggest that newly diagnosed patients, those with a high score on the DUSI-R psychiatric disorder scale, women, and subjects with high educational degrees may be at increased risk of non-adherence. Clinicians and policymakers should therefore pay special attention to these individuals, as non-adherence is a significant predictor of reduced response to treatment.Trial registration: EudraCT #: 2007-002111-82.BMC Psychiatry 01/2013; 13(1):36. · 2.55 Impact Factor
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ABSTRACT: To identify patterns of misuse and diversion of anxiolytic and sedative drugs among a sample of adults prescribed these drugs. Cross-sectional study. University research center in Canada. Sixty-seven adults (aged 19-61 yrs) who had current prescriptions for anxiolytic or sedative drugs. Face-to-face interviews and questionnaires were used to gather information on demographics as well as variables relating to drug misuse and diversion such as personality dimensions, psychiatric symptoms, and other substance use. Of the 67 participants, 36 (54%) reported misusing their drugs on at least one occasion, and 35 (52%) reported diverting their drugs at least once. A variety of forms of anxiolytic or sedative misuse were reported, including exceeding the recommended dosage (28 participants [42%]), deliberately using the drug with alcohol or another drug (27 [40%]), or taking it by an alternate route of administration (5 [7%]). Misuse and diversion were associated with a history of substance use and substance-related problems, as well as personality characteristics relating to impulsivity and hopelessness. Diversion was also associated with an increased likelihood of having taken any psychoactive prescription drug without having a valid prescription for it. A variety of forms of drug misuse and diversion occurred among this population of adults who were prescribed anxiolytics or sedatives. Likelihood of engaging in misuse or diversion was associated with other substance use, substance use disorders, and personality characteristics. Despite the modest sample size and cross-sectional design, this study identified substantial heterogeneity in prescription anxiolytic and sedative misuse, suggesting that the use of clearly defined operational criteria will be essential in future efforts to further characterize this phenomenon.Pharmacotherapy 03/2011; 31(3):262-72. · 2.90 Impact Factor