Abstract
David John Smith and Sergei Yukhnevich, Selby Old Age Psychiatry Centre, Shenton Park, Western Australia:
We describe three patients in an Old Age Psychiatry Unit (OAPU) suffering from dementia, with no prior psychiatric history, who deteriorated on rivastigmine. In the three cases treatment was initiated following requests from the family who had been exposed to positive publicity concerning this agent. The patients improved following discontinuation of rivastigmine.
The cholinesterase inhibitors, donepezil and rivastigmine, inhibit cholinesterase enzymes that break down acetylcholine and prolong its activity on cortical cholinergic receptors, which are believed to play a role in the dementing process. In recent studies rivastigmine diminished hallucinations, delusions and depression in patients with Lewy bodies dementia [1]. It lessened troublesome behaviours in patients scoring 6–15 on Mini Mental State Examination (MMSE) diagnosed with ‘probable’ Alzheimer's disease [2].
The first patient was a 71-year-old man with a 4-year history of dementia. Computed tomography (CT) showed generalized cerebral atrophy. He had been misinterpreting his image in the mirror. He was admitted frightened and agitated to the OAPU from home where treatment with risperidone had been ineffective. It was not possible to conduct a MMSE. Medication was ceased and the patient settled quickly. His wife hoped that rivastigmine would ‘cure’ her husband and it was commenced. In the first month the patient became unsettled, angry and resistive. He was unable to sit still or eat his meal. He chewed his clothes and plastic containers. He became incontinent of faeces. He now did not recognize his family. The patient settled within 2 months of discontinuing rivastigmine.
The second patient was a 68-year-old woman, diagnosed with dementia a year prior to admission. Magnetic resonance imaging showed prominent ventricles and multiple foci of white matter ischaemia. The patient was admitted to the OAPU from home depressed and irritable. Her MMSE was 13/29. She responded well to sodium valproate and olanzapine. Then, within 10 days of initiating treatment with rivastigmine she became more irritable and agitated. She physically attacked her husband and exhibited bizarre behaviour (e.g. walking around with a towel hanging on her nose). After ceasing rivastigmine she settled to her former state.
The third patient was a 86-year-old man with a 2-year history of cognitive decline. His MMSE was 18/30 and CT demonstrated general atrophy. Incongruously he had recently passed his driving test. One month prior to admission a physician prescribed rivastigmine following which the patient became confused. He mistook his wife for his mother and young people in the city for hisold ‘war’ friends. He was first admitted to a general hospital after exhibiting resistive and aggressive behaviour and then transferred to the OAPU where, after discontinuing rivastigmine he settled within a few days.
At the present time physicians are under pressure to actively treat Alzheimer's disease with rivastigmine even though there is little independent research in this field and in clinical practice it is difficult to differentiate the type of dementia to accurately fulfil the criteria for treatment. In our experience what could be considered excessive and unnecessary treatment for dementia has increased patient distress and caused family disappointment.