This is a protocol for a Cochrane Review (Intervention). The objectives are as follows:

Primary objective
* To evaluate the efficacy and safety of pharmacological interventions for the treatment of daytime somnolence in PD.
Secondary objectives:
* To address the spectrum of pharmacological strategies proposed for the treatment of daytime somnolence in PD.
* To address the methodological quality of trials on the treatment of daytime somnolence in PD.