Study to Compare the Effect of Ropinirole Prolonged Release Once-daily Versus Twice-daily

An Open-label, Multi-center, Crossover Study to Compare the Effect of Once-daily Ropinirole PR and Twice-daily Ropinirole PR in Patients With Parkinson Disease

1. In order to compare the benefit, side effects, and patient preference of Ropinirole prolonged release when used in once-daily or twice-daily dosing
2. In order to estimate the conversion rate of dopamine agonists into Ropinirole prolonged release

1. Study subjects : Parkinson disease who are on Ropinirole immediate release or Pramipexole immediate release and are considering to change into Ropinirole prolonged release

2. Cross over study design:

   • Group 1: once daily dose for 2 month then into twice daily in divided dose for 2 months
   • Group 2: twice daily in divided dose for 2 months then into once daily dose for 2 months

3. Dose adjustment may be done in the first 4 weeks.

4. Compare the benefit,side effects, and patient preference between the once daily vs twice daily dosing.

Inclusion Criteria:

1. Age: 30-80
2. Parkinson disease
3. On dopamine agonists (Ropinirole IR or Pramipexole IR) and are considering to change into Ropinirole PR
4. On stable antiparkinsonian medication for at least 4 weeks
5. Who signed consent to the study

Exclusion Criteria:

1. Who are on less than 2 mg of Ropinirole IR or 0.375 mg of Pramipexole IR
2. Who have dementia, psychosis, major depression and other serious neurological or medical problems
3. Who are allergic to the similar medications
4. Who has history of heavy metal poisoning
5. Who were on othe clinical trials of other medications within the last 4 weeks
6. Whoa re pregnant or lactating
7. Who are considered not eligible by the investigator