Background Elderly patients have a higher risk of adverse reactions associated with drugs with anticholinergic properties. Anticholinergic drugs may produce cognitive impairment, delirium and falls and can increase functional dependence.

Purpose To determine the extent of anticholinergic exposure in older people at admission to an internal medical ward. To assess the association between this exposure and anticholinergic adverse effects using two different scales.

Material and methods Observational and retrospective study of elderly patients (≥75 years old) admitted to an internal medical ward in March and April 2014. Total anticholinergic risk was assessed by the Anticholinergic Risk Scale (ARS) and the Anticholinergic Cognitive Burden Scale (ACB). The two scales consider in a different way the drug-associated risk of developing an anticholinergic symptom. Data were obtained from emergency reports while admitting to the internal medical ward and from the pharmaceutical management program Farmatools.

Results 148 patients, 49.3% men. Mean age: 84.8 ± 5.4 (75–97). Mean drugs prescribed at admission: 8.4 ± 3.8 (1–20). 86.5% lived at home and 13.5% in a nursing home. 10.3% died during admission. According to the ARS and ACB scales, 28.4% and 62.2% of patients were taking an anticholinergic drug at admission. 37.2% of patients had an anticholinergic symptom.

Results from the ARS scale showed a statistically significant association between taking an anticholinergic drug and developing an anticholinergic symptom (p = 0.008) OR = 6.76. No association was found with the ACB scale (p = 0.485).

42 patients were taking at least one anticholinergic drug at admission, according to the ARS scale. This predicts a grade 1 risk: levodopa-carbidopa, quetiapine, trazodone 19% each; paroxetine 11.9% and risperidone 9.5%. Grade 2 risk: tolterodine 4.7% and amantadine, olanzapine and baclofen 2.4% each. Grade 3 risk: tizanidine and amitriptyline 4.8% each. Average extent of anticholinergic exposure was 1.5 ± 0.74. At discharge, at least one anticholinergic drug was removed from 14.3% of these patients.

Conclusion A high percentage of elderly patients admitted to an internal medical ward were taking an anticholinergic drug. In our study, we found a correlation between anticholinergic exposure as defined by the ARS scale and adverse anticholinergic symptoms.

The ARS scale predicts an association between the taking of an anticholinergic drug and the development of an anticholinergic symptom (6.76 times higher risk).

References and/or acknowledgements No conflict of interest.