Drug treatment of dementia with Lewy bodies and Parkinson's disease dementia - common features and differences

Drug treatment of dementia with Lewy bodies and Parkinson's disease dementia - common features and differences Parkinson's disease dementia (PDD) and dementia with Lewy-bodies (DLB) have neuropathologically, clinically, and neurochemically much in common. Predominant clinical difference is the time pattern of cognitive and motor symptoms. In the course of both conditions psychotic symptoms are common and often induced by antiparkinsonian medication. Treatment of psychotic symptoms with antipsychotics is frequently not tolerated. Cholinesterase inhibitors are a therapeutic alternative for treating psychotic and cognitive symptoms in both conditions. Memantine potentially deteriorates psychotic symptoms. Benzodiazepines are not recommended for long-term treatment in dementia. Low-dose clozapine treatment is acknowledged usual practise for psychosis in Parkinson's disease and a case report indicates efficacy for psychosis in DLB, too. All other atypical antipsychotics except risperidone are not licensed for dementia, but risperidone is contraindicated in DLB due to manufacturer's notice and usually not well tolerated in Parkinson's disease. Open trials indicate safety and efficacy for treatment of psychosis in PDD and DLB with quetiapine. Unfortunately randomized controlled trials indicate, that quetiapine is less effective than clozapine against psychotic symptoms in both conditions, unless comparatively safe. But one case of a malignant neuroleptic syndrome in a DLB-patient treated with quetiapine has been published. Parkinsonism in DLB-patients responds worse to levodopa compared to patient with Parkinson's disease. Anticholinergic drugs often induce delirium in demented patients and therefore should be avoided. The same problem is associated with dopamine agonists in PDD and DLB. Amantadine, a NMDA-receptor antagonist as me mantine, potentially bears the same risk of worsening psychotic symptoms in both conditions. The following preliminary recommendation for drug treatment of PDD and DLB can be given: Stop all anticholinergic medication and reduce L-Dopa and other antiparkinsonian medication to the tolerated minimum. Levodopa alone is preferred. Treat with cholinesterase inhibitors to the maximum tolerated dose. If there is no adequate response regarding psychotic symptoms, add quetiapine. If this approach fails, replace quetiapine by low-dose clozapine. If behavioural disturbances are due to depression, anxiety, or irritability, treatment with an antidepressant, preferably citalopram, is an option.