Pharmacotherapy assessment and adverse drug reactions in older patients admitted to intensive care.

Introduction: Older patients are more susceptible to medication use, and physiological changes resulting from aging and organic dysfunctions presented by critically ill patients may alter the pharmacokinetic or pharmacodynamic behavior. Thus, critically ill older people present greater vulnerability to the occurrence of pharmacotherapeutic problems.

Objective: To evaluate pharmacotherapy and the development of potential adverse drug reactions (ADRs) in older patients admitted to an intensive care unit (ICU).

Method: A cohort study was conducted in an ICU for adults of a Brazilian University Hospital during a 12-month period. The patients' pharmacotherapy was evaluated daily, considering the occurrence of ADRs and drug-drug interactions (DDIs), the use of potentially inappropriate medications (PIMs) for older people, and the pharmacotherapy anticholinergic burden (ACB). A trigger tool was used for active search of ADRs, with subsequent causality evaluation. PIM use was evaluated by means of the Beers criteria and the STOPP/START criteria. The ABC scale was employed to estimate ACB. The Micromedex® and Drugs.com® medication databases were employed to evaluate the DDIs.

Results: The sample of this study consisted of 41 patients, with a mean age of 66.8 years old (±5.2). The 22 triggers used assisted in identifying 15 potential ADRs, and 26.8% of the patients developed them. The mean estimated ACB score was 3.0 (±1.8), and the patients used 3.1 (±1.4) and 3.3 (±1.6) PIMs according to the Beers and the STOPP criteria, respectively. A total of 672 DDIs were identified, with a mean of 16.8 (±9.5) DDIs/patient during ICU hospitalization. Our findings show an association between occurrence of ADRs in the ICU and polypharmacy (p=.03) and DDIs (p=.007), corroborating efforts for rational medication use as a preventive strategy.

Conclusions: Using tools to evaluate the pharmacotherapy for older people in intensive care can assist in the recognition and prevention of pharmacotherapeutic problems, with emphasis on the identification of ADRs through the observation of triggers and subsequent causality analysis.