To find out if a single dose of Parcopa®, a form of levodopa that dissolves in your mouth, works faster than regular oral levodopa which is swallowed, in fluctuating PD patients.

• Drug: Parcopa
• Drug: carbidopa-levodopa

• Experimental: Parcopa at equivalent dosage to subjects surrent stable dose
• Active Comparator: carbidopa-levodopa at subjects current stable dose

Inclusion Criteria:

• Male or female between the age of 31 and 80 -Diagnosis of idiopathic Parkinson's disease for at least three years duration
• Patients requiring levodopa for their PD
• Good subjective response to levodopa
• Fluctuating symptoms defined by wearing off phenomenon, any dyskinesia, and/or dose failures
• A UPDRS -off- motor score of at least 25
• Subjects willing to give informed consent
• Subjects who are able and willing to comply with study procedures

• If female of child-bearing potential, will use one of the approved birth control measures:

  1. Hormonal contraceptives
  2. Spermicidal and barrier
  3. Intrauterine device
  4. Partner sterility

Exclusion Criteria:

• Subjects with evidence of significant dementia
• Subjects with significant oral lesions
• History of unstable cardiac disease including angina or congestive heart failure within 3 months prior to study entry
• History of clinically significant renal disease including renal insufficiency of sufficient degree to require adjunctive treatment or dietary restrictions
• History of clinically significant hepatic disease, including previously documented cirrhosis or hepatic insufficiency or jaundice within 3 months prior to study entry.
• Subjects with poor response to levodopa
• Women who are pregnant, breast-feeding, or planning to become pregnant during this study are excluded from participation due to unknown effects of the study drug on the fetus.