Piribedil (ET 495) in the treatment of Parkinson's disease combined with amantadine or levodopa.

The further therapeutic benefit of piribedil when combined with amantadine or Levodopa was studied by a double-blind, cross-over trial in 15 patients with Parkinson's disease. A significant improvement at the 5 per cent level for akinesia, gait, speech disorder and facial expression occurred when piribedil was added to Levodopa; and a more highly significant improvement at the 1 per cent level for akinesia, facial expression and finger dexterity occurred with piribedil and amantadine. No significant improvement occurred for special timed tests. Improvement was associated with side effects in both groups of patients. Side effects occurred with both placebo and active piribedil. Only nausea during piribedil and Levodopa treatment reached statistical significance when compared with the placebo. Piribedil did not give rise to any haematological or biochemical complications. Our findings suggest that piribedil is of further therapeutic benefit when added to amantadine or Levodopa. It was suggested that the improvement which occurred together with amantadine could be due to the combined action of both drugs on dopamine receptors.