Adverse drug reactions in elderly subjects hospitalized in a specialized dementia management unit

Abstract

Introduction: Drug prescriptions represent an actionable item in the prevention of adverse drug reactions (ADRs). The aims of this study were to identify risk factors for the occurrence of ADRs, and to describe symptoms and drug interactions.

Methods: This was a longitudinal study over a period of 19 months in an acute geriatric ward specializing in the management of dementia. Independent risk factors for ADRs were identified by logistic regression. Drug interactions were also recorded.

Results: In total, 293 patients were included (age 82 ± 8 years). The prevalence of ADRs was 24 %. Patients were taking 8 ± 3 drugs per day; 72 (24.6 %) were taking more than three psychotropics. The main therapeutic classes prescribed were anxiolytics and hypnotics (57.7 %), antidementia drugs (54.6 %), antidepressants (54.3 %), antithrombotics (54.0 %), angiotensin-converting enzyme inhibitors [ACEIs] or angiotensin II receptor blockers [ARBs] (37.5 %). The risk of ADRs was significantly higher in patients taking neuroleptics (odds ratio [OR] 2.04; 95 % confidence interval [CI] 1.06-3.92), ACEIs/ARBs (OR 2.07; 95 % CI 1.13-3.77) and antidementia drugs (OR 1.84; 95 % CI 1.01-3.36). The risk of serious ADRs was significantly higher in patients taking ACEIs/ARBs (OR 2.95; 95 % CI 1.40-6.21), type I, III or IV antiarrhythmics (OR 2.71; 95 % CI 1.07-6.88) or neuroleptics (OR 2.42; 95 % CI 1.09-5.40). Drug interactions were involved in 26.3 % (n = 21) of ADRs; the combination of an ADR plus a drug interaction was associated with increased severity (p = 0.02).

Conclusion: Caution is needed when prescribing ACEIs/ARBs, neuroleptics, antidementia drugs, or certain types of antiarrhythmics in patients suffering from dementia. Psychotropics should be avoided because of the associated risk of ADRs and drug interactions.