Dyskinesias (AAN 2000 report)

Subject: Dyskinesias (AAN 2000 report)

Date: 5/3/2000

E-MOVE reports from the 52nd Annual meeting of the American Academy of Neurology, held in San Diego, California, 30 April-5 May 2000. Citation numbers below refer to abstracts of presentations and posters, which are published in Neurology 2000;54(suppl.3).

1. Pramipexole vs. levodopa in early Parkinson's disease: A randomized clinical trial
R Holloway and the Parkinson Study Group
S19.003

Onset of dyskinesia and wearing off can be delayed by beginning early PD therapy with pramipexole, rather than with levodopa, according to this study.

Three hundred and one early PD patients who required dopaminergic therapy were randomized to receive either pramipexole plus placebo LD, or LD plus placebo pramipexole. During the first 10 weeks, patients were allowed to adjust doses of their medications to achieve best symptom reduction. During the remainder of the 23.5-month trial, investigators could add open-label levodopa as needed. The primary endpoint was the time to any of three motor complications: wearing off, on-off, or dyskinesia.

Twenty-eight percent of pramipexole patients, and 51% of LD patients, reached the primary endpoint within the study period (p<0.0001). There were significant differences between groups in development of both dyskinesias and wearing off, but not on-off effects. Forty-eight percent of pramipexole patients required open-label levodopa, compared to 36% of levodopa patients (p=0.03). Mean improvement in disability was greater in LD-treated patients, with scores on the United Parkinson's Disease Rating Scale falling from 31.1 to 21.9 in the LD group, vs. 32.5 to 28.1 in the pramipexole group. The authors noted this difference remains to be explained, since the availability of open-label levodopa was meant to allow equalization of motor benefit.

2. Preliminary report: Use of sildenafil to treat dyskinesias in patients with Parkinson's disease
DM Swope
S19.006

Open-label sildenafil (Viagra) was effective in reducing dyskinesias in 7 of 9 patients with levodopa-induced dyskinesias. Patients (6 men, 3 women) with moderate-to-severe peak-dose dyskinesia received 25 mg sildenafil on two consecutive days, along with all normal antiparkinsonian medications, including amantadine, which has been shown to have mild antidyskinetic effects. Six patients reported partial-to-complete cessation of dyskinesias on sildenafil, which returned the day after treatment stopped. A seventh patient received no benefit at 25 mg, but reported decreased dyskinesias at 50 mg. Prior to this study, one patient had been using 25 mg sildenafil for over one year to treat dyskinesias. The author noted the preliminary nature of this finding, and the strong placebo effects common to small, open-label studies. Possible dependence of the effect on concurrent amantadine treatment remains to be determined.