Effect of age and arteriosclerosis on the response of Parkinsonian patients to levodopa.

Twenty-four patients with Parkinsonism were treated with levodopa for up to one year. Ten were aged under 65, 12 were aged 65 or over, and two were specifically included because they were considered to have arteriosclerotic Parkinsonism. These two patients showed no response to treatment. The 10 younger patients showed less clinical evidence of arteriosclerosis than the older ones, and responded significantly better to treatment with levodopa. Mean improvement was 61% in the younger group after 12 months' treatment and 28% in the older group. Improvement was greatest within three months of starting treatment. Abnormal movements which resulted from treatment with levodopa could be reduced with only slight loss of therapeutic benefit by the addition of tetrabenazine.

Incidence of side effects from levodopa during the introduction of treatment.

Twenty patients with Parkinsonism were investigated in order to establish whether the gradual introduction of treatment with levodopa allows a higher dose to be tolerated than can be achieved if treatment is introduced rapidly. No indication was obtained that slow introduction of treatment offers an advantage in maximum tolerated dose, and patients aged 65 and over responded similarly in this respect to those under 65. The maximum tolerated dose is slightly lower in the elderly patient. The incidence of the different side effects does not appear to be affected by the rate of increasing the dose of levodopa.