Drug interactions among older adults followed up in a comprehensive medication management service at Primary Care

Abstract

Objective: To estimate the prevalence of drug interactions and associated factors among older adults followed up in a Comprehensive Medication Management Service at Primary Care. Methods: Firstly, the Beers criteria 2015 was used to define drug interactions; later, drug interactions proposed by Dumbreck for patients with diabetes, depression, and heart failure were evaluated. The associated factors were assessed by univariate (Pearson's χ 2 ) and multivariate analyses (logistic regression). The significance level of 5% was set for all analyses. Results: The mean age of the studied population was 70.2±7.8 years; 52.2% were between 60 and 69 years, and 61.3% were female. Among the older adults, 94.5% used two or more drugs (condition for the occurrence of drug-drug interaction). The prevalence of drug interaction according to the Beers criteria was 4.9%. After multivariate analysis, diseases of the central nervous system, arrhythmia, number of medications, and female sex were positively associated with drug interaction. The prevalence of drug interaction according to Dumbreck was 27.2%. After multivariate analysis, the number of medications, the presence of heart failure, and Charlson comorbidity index greater than 1 were conditions positively associated with drug interactions. Conclusion: The holistic and individualized approach used in comprehensive medication management services for older patients is important, considering the prevalence of drug interactions and the need to minimize adverse events.

Drug interactions in the pharmacotherapy of patients included in primary care comprehensive medication management services

“…18,19 On the other hand, the older age detected causes concern, since the mean of potential DI identified was high (95.5%), and DI tend pose more threats to this population due to the considerable pharmacokinetic and pharmacodynamic changes caused by the aging process that can potentialize their adverse clinical consequences. [20][21][22] The mean of DI encountered (mean= 5.9 DI/patient) was, however, similar to that found in other studies 22,23 , and involved mainly the most commonly used drugs among the study's patients, as expected.…”

“…Therefore, the CMM service contributes to the deprescription of medications by proposing the suspension of those that are unnecessary, in order to avoid the patient experiencing adverse reactions (including those caused by DI) without any benefit in the use of the drug. 11,21 Our study showed that it is fundamental to analyze the DI in a clinically contextualized manner. Also, professionals who intend to perform such analysis should distinguish the DI that can be monitored from those that are not monitorable.…”

“…Many studies only report major DI, and, if this was the case in the present study, the most frequent potential DI would be "amlodipine + simvastatin" (n=23;16.3%). 21,24 However, it is important to point out that, in clinical practice, one should not consider only DI classified as "major", because those considered moderate can also cause serious damage, especially to more vulnerable patients, such as the older patients. 3,21 In this sense, the most frequent potential DI in this study (NPH insulin + metformin), despite being classified as "moderate" in severity, could contribute to serious hypoglycemia among the majority of older patients identified in the present study.…”

“…21,24 However, it is important to point out that, in clinical practice, one should not consider only DI classified as "major", because those considered moderate can also cause serious damage, especially to more vulnerable patients, such as the older patients. 3,21 In this sense, the most frequent potential DI in this study (NPH insulin + metformin), despite being classified as "moderate" in severity, could contribute to serious hypoglycemia among the majority of older patients identified in the present study. 25 According to the classification of the DI in terms of their monitorability, it was possible to verify that most DI were classified as monitorable (90.9%), but few were associated with a detectable clinical consequence (27%), very similar to that found by Dumbreck et al 24 These results reveal that the pharmacist could and should easily use clinical parameters to determine the existence of a DI whenever possible, since the identification of a potential DI in the pharmacotherapy does not necessarily reflect a clinical alteration.…”

Prevalence of Drug–Drug Interactions in Older Community-Dwelling Individuals: A Systematic Review and Meta-analysis

“…Most studies (n = 23) used a cross-sectional design. Studies ranged in [20,22,46,[48][49][50][51][52][53][54][55][56][57][58][59][60][62][63][64][65][66][67][68][69][70][71][72][73][74][75][76] reported DDI prevalence estimates using study participants as the unit of analysis, one study [75] also reported DDI prevalence using the total number of prescriptions as the unit of analysis, and one study [64] also reported DDI prevalence using the total number of drugs as the unit of analysis. One study [61] only reported the total number of drug combinations potentially leading to serious DDIs, and one study [47] only reported the proportion of PIMs that were due to DDIs.…”