Adverse drug reactions in patients with Alzheimer's disease and related dementia in France: a national multicentre cross-sectional study.

PURPOSE To assess the prevalence of adverse drug reactions (ADRs) occurring in patients with Alzheimer's disease (AD) or other dementia in France. METHODS A cross-sectional multicentre study was conducted by the French network of the 31 regional pharmacovigilance centres on a given day. The subjects were selected by random draw to be a representative sample of French patients with dementia: consultations of dementia clinics, nursing-homes, acute and long care geriatric units, rehabilitation care geriatric units. The staff of each medical structure together with that of the pharmacovigilance centre defined a day for including the patients. Socio-demographic data, history, ADR and drugs given were registered. RESULTS There were 1332 subjects included, 51.1% living at home, 48.8% in institutions, aged 82.0 ± 8.0 years (46-108); 61.3% suffered from AD. Mean number of drugs was 6.3 ± 3.1. Anti-dementia drugs were given to 66.4% subjects. ADR prevalence was 5.0% (95% CI: 3.9-6.2) without a significant difference between at home and institutionalized patients. ADR consisted of gastro-intestinal (23.2%), central nervous system (17.4%) and psychiatric disorders (8.7%). Of the ADR, 31.9% were serious, and 47.8% preventable. The drugs most often involved were anti-dementia (28.9%), cardio-vascular (28.9%) and psychotropic drugs (26.4%, anxiolytics, hypnotics, antidepressants, neuroleptics). CONCLUSION This national scale study showed that iatrogenesis in patients with AD and related dementia can at times be serious and preventable. Therefore, special attention is required when prescribing psychotropic and anti-dementia drugs, as they are frequently used and induce half of the ADR in this population.