Risperidone (Risperdal) for behavioural disturbances in dementia

Risperidone has been PBS-listed as an authority item for behavioural disturbances characterised by psychotic symptoms and aggression in patients with dementia where non-pharmacological methods have been unsuccessful. The listing applies to risperidone 500 microgram and 1 mg scored tablets, 500 microgram and 1 mg orally disintegrating tablets (Quicklet) and oral solution 1 mg per mL, 30 mL.

The Pharmaceutical Benefits Advisory Committee recommended listing on the basis of acceptable cost-effectiveness compared to haloperidol. Risperidone was considered to have a lower propensity for tardive dyskinesia than haloperidol.^1,2

Drug treatment has uncertain benefits and may cause serious adverse effects so is second-line treatment for behavioural disturbances in dementia. Managing underlying causes and non-drug strategies should be tried first.

Identifying and, where possible, modifying triggers for problem behaviours may help to avoid the need for drug therapy. Consider whether physical illness, depression, anxiety, the environment or interactions with others are contributing to behavioural disturbances.

It is difficult to recommend any non-drug strategy above another on the basis of current evidence. However, combinations of interventions tailored to the needs of individuals and carers may improve both patient behaviour and carer distress.^3,4

Risperidone produces modest improvements in problem behaviours characterised by psychosis and aggression. There is no conclusive evidence that it is any more effective than other drugs, but it is the only atypical antipsychotic that is both approved by the Therapeutic Goods Administration and PBS-listed for this indication.

Encourage carers and people with dementia to seek support and provide them with information about available services. The National Dementia Behaviour Advisory Service (ph. 1300 366 448) provides information to health professionals and carers about dealing with problem behaviours.

Elderly patients are more susceptible than younger patients to the adverse effects of risperidone. Extrapyramidal side-effects, postural hypotension and somnolence are dose-related.⁵ Consider each patient's risk of cerebrovascular adverse events and diabetes mellitus; risperidone may increase the risk of both.

Starting doses and target doses should be lower and dose titration slower in the elderly than in younger patients. Consider ceasing or reducing the dose if adverse effects occur.

Regularly review the need for continuing therapy with a view to reducing the dose or ceasing. Behavioural disturbances may be short-lived, so drug therapy should not be prescribed indefinitely.