Use of Medicines with Anticholinergic and Sedative Effect Before and After Initiation of Anti-Dementia Medications

BACKGROUND People with dementia may be particularly sensitive to cognitive impairment induced by anticholinergic and sedative medicines. OBJECTIVE This study aimed to examine if utilisation of medicines with anticholinergic and sedative effects changed before and after initiation of anti-dementia therapy. METHODS A retrospective cohort study was conducted using Australian pharmacy claim data (Pharmaceutical Benefit Scheme). People with first (index) dispensing for a cholinesterase inhibitor or memantine between 1 January 2009 and 31 December 2010 who were aged 65 years or over at the time of initiation were included. The proportion who received sedatives or anticholinergics in the 6 months prior to and post initiation of anti-dementia therapy was determined. RESULTS The cohort included 24,110 patients, with over half aged 75-84 years. Overall, 30 % received any class of anticholinergic or sedative medicine for at least 1 month in the 6 months prior to initiation of anti-dementia agents, and 36 % post initiation. Some patients (6 %) ceased anticholinergics or sedatives post initiation even though they had them in the months prior. However, 12 % commenced therapy with anticholinergics or sedatives post anti-dementia therapy initiation even though they were naïve to them in the 6 months prior to therapy. CONCLUSION Medicines with anticholinergic or sedative effects were commonly dispensed in one-third of people with dementia. Prescribers need to consider a review of patients on anticholinergic therapy with cholinesterase inhibitors as the effectiveness of the cholinesterase therapy may be compromised.