Influence of genetic, biological and pharmacological factors on levodopa dose in Parkinson's disease.

Aim: Levodopa is first-line treatment of Parkinson's disease motor symptoms but, dose response is highly variable. Therefore, the aim of this study was to determine how much levodopa dose could be explained by biological, pharmacological and genetic factors.
Patients & Methods: A total of 224 Parkinson's disease patients were genotyped for SV2C and SLC6A3 polymorphisms by allelic discrimination assays. Comedication, demographic and clinical data were also assessed.
Results: All variables with p < 0.20 were included in a multiple regression analysis for dose prediction. The final model explained 23% of dose variation (F = 11.54; p < 0.000001).
Conclusion: Although a good prediction model was obtained, it still needs to be tested in an independent sample to be validated.