Are high doses of carbidopa a concern? A randomized, clinical trial in Parkinson's disease.

Recommended doses of carbidopa are 75-200 mg/day. Higher doses could inhibit brain aromatic amino-acid decarboxylase and reduce clinical effects. We compared 4-week outpatient treatments with carbidopa (75 and 450 mg/day) administered with L-dopa on the subjects' normal schedule.