Prevalence of potentially harmful multidrug interactions on medication lists of elderly ambulatory patients

Abstract

Background It has been hypothesized that polypharmacy may increase the frequency of multidrug interactions (MDIs) where one drug interacts with two or more other drugs, amplifying the risk of associated adverse drug events (ADEs). The main objective of this study was to determine the prevalence of MDIs in medication lists of elderly ambulatory patients and to identify the medications most commonly involved in MDIs that amplify the risk of ADEs. Methods Medication lists stored in the electronic health record (EHR) of 6,545 outpatients ≥60 years old were extracted from the enterprise data warehouse. Network analysis identified patients with three or more interacting medications from their medication lists. Potentially harmful interactions were identified from the enterprise drug-drug interaction alerting system. MDIs were considered to amplify the risk if interactions could increase the probability of ADEs. Results MDIs were identified in 1.3 % of the medication lists, the majority of which involved three interacting drugs (75.6 %) while the remainder involved four (15.6 %) or five or more (8.9 %) interacting drugs. The average number of medications on the lists was 3.1 ± 2.3 in patients with no drug interactions and 8.6 ± 3.4 in patients with MDIs. The prevalence of MDIs on medication lists was greater than 10 % in patients prescribed bupropion, tramadol, trazodone, cyclobenzaprine, fluoxetine, ondansetron, or quetiapine and greater than 20 % in patients prescribed amiodarone or methotrexate. All MDIs were potentially risk-amplifying due to pharmacodynamic interactions, where three or more medications were associated with the same ADE, or pharmacokinetic, where two or more drugs reduced the metabolism of a third drug. The most common drugs involved in MDIs were psychotropic, comprising 35.1 % of all drugs involved. The most common serious potential ADEs associated with the interactions were serotonin syndrome, seizures, prolonged QT interval and bleeding. Conclusions An identifiable number of medications, the majority of which are psychotropic, may be involved in MDIs in elderly ambulatory patients which may amplify the risk of serious ADEs. To mitigate the risk, providers will need to pay special attention to the overlapping drug-drug interactions which result in MDIs.

Prevalence and associated factors of drug-drug interactions in elderly outpatients in a tertiary care hospital: a cross-sectional study based on three databases

“…In Beers criteria, any combination of 3 or more CNS-active drugs needs to be avoided ( 24 ). Not only 2 drug interactions but also multiple drug interactions need to be considered ( 38 ). The lack of clinical relevance of the detected DDI should be addressed in upcoming studies, as this would provide more relevant information for prescribers in clinical practice.…”

Drug Interaction in Institutionalized Elderly People

“…Psychoactive drugs have been the focus of attention in prescriptions among elderly individuals [26], especially those in institutions, where their use is more widespread [27,28]. Psychotropic drugs were reported to be responsible for 35% of the drugs involved in drug interactions among outpatients [29]. Neuroleptics are the most widely used psychoactive drugs in ILPIs and contribute to an increased risk of arrhythmias and nervous system depression when in combination with other drugs [5].…”

Recent Updates on Risk and Management Plans Associated with Polypharmacy in Older Population

“…Polypharmacy may sometimes lead to “prescribing cascades.” A prescribing cascade arises when signs and symptoms (multiple and nonspecific) of an ADR are misinterpreted as a disease and a new treatment/drug therapy is further added to the earlier prescribed treatment to treat the condition. This increases the potential to develop further side-effects, leading to a prescribing cascade [ 51 ]. It has been proposed earlier by several groups of researchers that the use of multiple medications comes with an increased risk for negative health outcomes, such as higher healthcare costs, ADEs, drug–drug interactions, medication non-adherence, decreased functional status, and geriatric syndromes [ 52 , 53 , 54 , 55 ].…”