The prevalence of potential drug-drug interactions in adults with intellectual disability.

BACKGROUND: There is a high use of medications in adults with intellectual disability (ID). One implication of taking multiple medications is the potential for drug-drug interactions (DDIs). However, despite this being well highlighted in the mainstream literature, little is known about the incidence or associations of DDIs in the ID population. METHODS: This study describes the prevalence, patterns and associations of potential DDIs in a total administrative sample of adults with ID known to services in Jersey. Demographic, health-related and medication data were collected from 217 adults known to ID services. Data were collected using a face-to-face survey. The Anatomical Therapeutic Chemical classification system was used to categorise medications, and Stockley's Drug Interaction Checker was used to classify potential DDIs. Drug-drug pairings were considered to be of clinical significance if they were to be 'avoided, adjusted, monitored or required further information'. RESULTS: Potential DDIs of clinical significance were common. Exposure to potential DDIs of clinical significance was associated with being female, taking more than five medications (polypharmacy), living in residential care and having more health conditions. A simple regression was used to understand the effect of number of prescribed medications on potential DDIs of clinical significance. Every prescribed drug led to a 0.87 (95% confidence interval: 0.72-1.00) increase in having a potential DDI of clinical significance. CONCLUSION: Adults with ID who live in residential care, who are female, exposed to polypharmacy and have more health conditions may be more likely to have potential DDIs of clinical significance. Urgent consideration needs to be given to the potential of DDIs in this population given their exposure to high levels of medication.

Polypharmacy and psychotropic polypharmacy in adults with intellectual disability: a cross-sectional total population study.

BACKGROUND: Adults with intellectual disability (ID) are prescribed high levels of medication, with polypharmacy and psychotropic polypharmacy common. However, reported rates vary between studies, and there has been an over-reliance on obtaining data from convenience samples. The objective of this study was to determine the prevalence of medication use and polypharmacy in a population-level sample of adults with IDs. Factors associated with polypharmacy and psychotropic polypharmacy are explored. METHODS: We used a total population sample of 217 adults with IDs known to services in Jersey (sampling frame n = 285). The Anatomical Therapeutic Chemical classification system was used to categorise medications that participants were currently taking on a regular basis. We examined associations of polypharmacy and psychotropic polypharmacy with socio-economic status, health and demographic variables using univariate and multivariate analyses. RESULTS: A total of 83.4% of participants were prescribed medication, with high doses common. Of the participants, 38.2% were exposed to polypharmacy while 23% of participants were exposed to psychotropic polypharmacy. After controlling for demographic, health and socio-economic characteristics, polypharmacy was significantly associated with older age, increased severity of ID, living in a residential setting and having increased comorbidities. Psychotropic polypharmacy was associated with being male, being aged 50+ years and having had a psychiatric diagnosis over the life course. Being prescribed psychotropic drugs above the defined daily dose was not associated with having had a psychiatric diagnosis over the life course, suggesting the possibility of 'off label' prescribing. CONCLUSIONS: Our results indicate that medication use, in high doses, alongside polypharmacy and psychotropic polypharmacy are highly prevalent in adults with ID. The exposure to multiple medications increases the risk of developing adverse drug events, drug-drug interactions and medication-related problems. Future population-level, prospective cohort studies should examine the prevalence of polypharmacy and psychotropic polypharmacy using standardised definitions and consider the potential impact of adverse drug events, drug-drug interactions and medication-related problems in this population.

Prevalence of psychotropic medication use and association with challenging behaviour in adults with an intellectual disability. A total population study.

BACKGROUND: There is a high prevalence of psychotropic medication use in adults with Intellectual Disabilities (ID), often in the absence of psychiatric disorder, also associated with challenging behaviour. Previous research has focused on specific sample frames or data from primary care providers. There is also a lack of consistency in the definition of challenging behaviour used. METHODS: We adopted a total population sampling method. Medication data on 265 adults with ID were classified according to the Anatomical Therapeutic Chemical classification system. The Behaviour Problems Inventory - short form classified challenging behaviours. We examined the association between challenging behaviour and the use of psychotropic medication, and whether any association would still be present after accounting for socio-demographic and clinical characteristics. RESULTS: 70.57% of adults with ID were prescribed at least one class of any medication (mean per person =2.62; range 0-14). Psychotropic medications were used by 37.73% of participants with antipsychotics the commonest type used by 21.89% of individuals. Polypharmacy and high dosages were common. Generalised Linear Models indicated significant associations between psychotropic medication and the presence of a psychiatric diagnosis, challenging behaviour, older age and type of residence. Male gender was additionally associated with antipsychotic medication. CONCLUSIONS: The use of a total population sample identified via multiple routes is less likely to overestimate prevalence rates of medication use. Current challenging behaviour was a predictor of medication use after controlling for other variables. Data indicate that there may be differences in prescribing patterns associated with different topographies of challenging behaviours.