The initial treatment of patients with early Parkinson’s disease (PD)
should be individualised according to the profile of the patient and the drug,
according to the Parkinson Study Group.
The group found that patients treated initially with the dopamine agonist pramipexole
(Mirapexin) developed fewer dopaminergic motor complications than those given
levodopa but were likely to perform less well overall (Journal of the American
Medical Association 2000;284:1931).
The group compared the effect of levodopa with pramipexole on the time taken
to develop dyskinesia, “wearing-off”, or “on-off” fluctuations,
and on the score reached on a standard scale for measuring disease severity.
They found that, by the end of the study period, 28 per cent of the subjects
given pramipexole had suffered their first motor complication compared with
51 per cent of those taking levodopa. However, patients taking levodopa achieved
a higher (ie, better) mean score on the Unified Parkinson’s Disease Rating
Scale than those receiving pramipexole (9.2 and 4.5, respectively).
Significantly more patients in the pramipexole group experienced somnolence,
hallucinations and oedema than those in the levodopa group. Two subjects from
the pramipexole group and one who had been taking levodopa reported falling
asleep while driving. The trial involved 301 patients with early Parkinson’s
disease who were followed up for 23.5 months.
In a commentary on the study (Ibid, p1971), Dr Caroline Tanner (Parkinson’s
Institute, Sunnyvale, California, US) suggests that using a dopamine agonist
initially might be useful for reducing the frequency of dyskinesia in patients
for whom it is embarrassing, in cases where impairment of fine motor tasks is
a problem or for patients who require a predictable level of motor performance.
However, the risks and benefits of using dopamine agonists initially have yet
to be determined in older patients or for those with other illnesses or dementia.