Effects of Anticholinergic Drugs on Verbal Episodic Memory Function in the Elderly

Background An increasing number of medications that are frequently prescribed to elderly patients have been identified as having weak but definite anticholinergic properties. Few epidemiological studies have evaluated the impact of these drugs on verbal episodic memory using sensitive and specific neuropsychological testing in an elderly population presenting with cognitive impairment. Objectives The aim of this study was to assess the effect of drugs with anticholinergic properties on verbal episodic memory function in elderly patients presenting for memory evaluation. Study Design We performed a retrospective, cross-sectional study that included 134 consecutive elderly outpatients who attended the daycare memory unit of Centre Hospitalier Sud, Lyon, France. We searched the MEDLINE database (1973–2008) to identify drugs with anticholinergic properties. All drugs with well known anticholinergic activity, mild reported anticholinergic effects or in vitro anticholinergic activity were included in the study. Measurements We used the Free and Cued Selective Reminding (FCSR) test to evaluate verbal episodic memory. Results The mean±SD number of drugs with anticholinergic properties taken by the subjects was 0.64±0.82. Fifty percent of the subjects (n = 67) had a prescription for at least one drug with anticholinergic properties and 16% (n = 21) had a prescription for two or more. Drugs with anticholinergic properties most frequently prescribed in our cohort were cardiovascular (furosemide, hydrochlorothiazide, digoxin), antidepressant (paroxetine, sertraline, fluoxetine) and antispasmodic (oxybutynin chloride) drugs. The number of drugs with anticholinergic properties that subjects were taking was associated with reduced performance on tasks that assessed verbal memory (p < 0.05). Neuropsychological test batteries revealed a significant unfavourable effect of use of drugs with anticholinergic activity on episodic verbal memory. Tests evaluating other cognitive functions were not affected by use of drugs with anticholinergic activity. These associations remained following multivariate analysis adjusting for age, sex, education level, number of anticholinergic drugs, number of co-morbidities, diagnosis, behavioural symptoms and depressive symptoms. Conclusion Clinicians should assess the current use of drugs with anticholinergic properties in the elderly, particularly in patients presenting for memory evaluation. In such cases, use of other therapeutic alternatives should be considered.