A pilot study evaluating the efficacy and safety of rivastigmine in patients with mixed dementia

The two most common causes of dementia in the elderly are Alzheimer's disease (AD) and vascular dementia (VaD), which can coexist as mixed dementia. The object of this study was to assess the efficacy and safety of rivastigmine in patients with mixed dementia (AD with VaD).

This 26-week open-label pilot study was conducted at 19 centres in the US. To reduce bias, the Alzheimer's Disease Assessment Scale-Cognitive (ADAS-Cog) raters were blinded to all efficacy measures and to patient dosage information. Patients were treated with rivastigmine and titrated to their highest tolerated dose, up to 12 mg/day (6 mg twice daily). The primary efficacy measure was cognitive function assessed by the ADAS-Cog subscale (without the concentration/distractibility item, to be consistent with cognitive outcome measures used in previous rivastigmine trials).

Forty-seven percent of patients treated with rivastigmine 6-12 mg/day demonstrated improvement on the ADAS-Cog at 26 weeks, with >25% of patients having a clinically significant improvement of > or =4 points. Treatment with rivastigmine (6-12 mg/day) was well tolerated by the majority of patients. The most common adverse effects occurring in >10% of patients were nausea, vomiting, dizziness and diarrhoea.

This pilot study suggests that rivastigmine treatment may have beneficial effects in the treatment of patients with mixed dementia.