Dopaminergic treatment has ‘minor impact’ on autonomic symptoms in Parkinson’s

By Nikki Withers, medwireNews Reporter

Norwegian researchers say that dopaminergic treatment should be considered for patients with early Parkinson's disease after finding that dopaminergic medication only has a minor impact on autonomic symptoms after 1 year.

The team, led by Bernd Müller (Haukeland University Hospital, Bergen), investigated the impact of dopaminergic treatment on autonomic symptoms in 171 patients with Parkinson's disease. All patients were drug-naïve at inclusion.

Orthostatic blood pressure and autonomic symptoms, assessed using a preliminary version of the Movement Disorder Society-sponsored new version of the Unified Parkinson's Disease Rating Scale (pMDS-UPDRS; range 0-4), were examined at baseline and 12 months after initiation of dopaminergic treatment.

In all, 82% of patients received dopaminergic treatment for the 12-month study period.

The researchers report that, overall, severity scores of autonomic symptoms changed only slightly within the first year from diagnosis in both treated and untreated patients. In treated patients, the mean severity score for constipation was slightly increased after 1 year (pMDS-UPDRS 0.43 at baseline vs 0.56 after 1 year).

Slight changes in the orthostatic reaction of treated, but not untreated patients, were observed after 12 months, including a tendency to increased lightheadedness and lowered blood pressure when standing. However, the number of patients with orthostatic hypotension did not increase significantly, and decreases in blood pressure related to orthostatism were virtually unreported.

Of note, Müller and colleagues found a tendency for improved dysphagia in treated patients. "Our results encourage optimizing dopaminergic treatment in patients suffering from dysphagia, as improvement may be achieved in some individuals and prevent discomfort and complications like aspiration," they say.

The researchers conclude that dopaminergic treatment has a rather minor impact on autonomic symptoms in patients with early and previously untreated Parkinson's disease. As such, the autonomic side effects of dopaminergic treatment in early Parkinson's disease "should normally not represent a major concern for the treating physician."

However, they warn that higher doses of dopaminergic drugs "may provoke more prominent changes."

The findings are published in Acta Neurologica Scandinavica.

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