Box 4.

Anticholinergic burden scales.

Anticholinergic burden scales have been developed, typically based upon expert opinion, to categorize medications in terms of anticholinergic activity.98 Possible anticholinergic drugs only have evidence from in vitro studies reporting antagonistic activity at the muscarinic receptor (score of 1). Definite anticholinergic drugs have reported anticholinergic adverse effects (score of 2) or delirium (score of 3) from a more substantial evidence basis (literature, prescriber’s information or expert opinion).100 The scales can be used to calculate a score that reflects the patient’s cumulative exposure to anticholinergic effects. This overall score can be used to identify whether clinicians should consider alternative medications, and can be applied to hospital inpatients, patients within the community, or patients within institutional care. However, it should be noted that there is not a standard, validated rating scale for the assessment of anticholinergic burden. Examples include: (1) Anticholinergic Cognitive Burden Scale100,101 (2) Anticholinergic Drug Scale102 (3) Anticholinergic Risk Scale103