J Clin Mov Disord 2014 26;1. Epub 2014 Nov 26.

Departments of Neurology, Neurosurgery and Psychiatry, McKnight Brain Institute, University of Florida, 100 S Newell Dr Rm-L3-101, Gainesville, 32611 FL USA.

Background: To determine if testosterone levels are influenced by dopaminergic therapy in Parkinson disease (PD) patients. Testosterone level has been reported to be low in patients with PD and other neurodegenerative diseases. In this study, we sought to determine whether dopaminergic therapy (i.e. levodopa and dopamine agonist) influenced testosterone levels. We used a cohort of consecutive male patients from the INSPECT trial--a multi-center, prospective, study that primarily investigated the effects of short-term treatment with pramipexole or levodopa on [(123)I] B-CIT SPECT imaging in early PD.

Methods: Testosterone levels were drawn on consenting male subjects with early PD who enrolled in the INSPECT trial at three study visits (baseline, 12 weeks post-treatment, and 8-12 weeks post-washout). Subjects were randomized to: no treatment, pramipexole (up to 3 mg) or levodopa (up to 600 mg). Testosterone levels were obtained twice (prior to 10 AM) and averaged for each of three study visits.

Results: Thirty two male patients participated in this sub-study and there were no significant differences in disease characteristics in the 3 groups at baseline. Twenty-nine patients completed the follow-up visits and were suitable for analysis. There were statistically significant differences in the change in free testosterone level, increased in both the levodopa group and pramipexole group but decreased in the untreated group at 12-weeks post-treatment. There were no significant differences in the changes of UPDRS total or motor scores, although there was a strong trend toward improvement in motor scores. The testosterone level persisted in its increase only in the pramipexole group at the end of the washout period.

Conclusion: These preliminary data support the premise that dopaminergic medications do not reduce testosterone levels in early PD patients.

JAMA 2000 Oct;284(15):1931-8

Context: Pramipexole and levodopa both ameliorate the motor symptoms of early Parkinson disease (PD), but no controlled studies have compared long-term outcomes after initiating dopaminergic therapy with pramipexole vs levodopa.

Objective: To compare the development of dopaminergic motor complications after initial treatment of early PD with pramipexole vs levodopa.

Design: Multicenter, parallel-group, double-blind, randomized controlled trial. Read More

JAMA 2002 Apr;287(13):1653-61

Context: Pramipexole and levodopa are effective medications to treat motor symptoms of early Parkinson disease (PD). In vitro and animal studies suggest that pramipexole may protect and that levodopa may either protect or damage dopamine neurons. Neuroimaging offers the potential of an objective biomarker of dopamine neuron degeneration in PD patients. Read More

Arch Neurol 2009 May;66(5):563-70

Department of Neurology, University of Rochester, 1351 Mt Hope Ave, Ste 220, Rochester, NY 14620, USA.

Objective: To compare the long-term outcomes of subjects initially treated with pramipexole dihydrochloride with those of subjects initially treated with levodopa in the Comparison of the Agonist Pramipexole With Levodopa on Motor Complications of Parkinson's Disease (CALM-PD) trial.

Design: Up to 2 years of open extended follow-up of the CALM-PD subjects.

Setting: Academic movement disorders clinics at 22 sites in the United States and Canada. Read More

JAMA 1997 Jul;278(2):125-30

Context: Monotherapy with dopamine agonists may be useful in early Parkinson disease.

Objective: To evaluate dose-response relationships for tolerability, safety, and efficacy of the synthetic dopamine agonist pramipexole.

Design: Multicenter, multidosage, parallel-group, double-blind, placebo-controlled, randomized clinical trial. Read More