State-of-the-art pharmacotherapy for autonomic dysfunction in Parkinson's disease.

Introduction : Autonomic dysfunction is one of the most frequent and disabling non-motor symptoms of Parkinson's disease (PD). It includes, among others, orthostatic hypotension (OH), sialorrhea, constipation, erectile dysfunction (ED), urinary dysfunction, and diaphoresis. They are usually under-recognized and suboptimally managed. Areas covered : Recommended treatments for dysautonomias are summarized with a description of the mechanism of action and observed results. The pathophysiology of each disorder is reviewed to pinpoint possible therapeutic targets. Drugs approved for treating dysautonomia in the general population along with those under development for PD-related dysautonomia are also reviewed. Finally, the key elements of each symptom that should be addressed in clinical trials' design are considered. Expert opinion : Midodrine, droxidopa, fludrocortisone, and domperidone may be used for OH treatment. Sialorrhea can be managed with botulin toxin injections and oral glycopyrrolate. Erectile dysfunction can benefit from sildenafil treatment, as urinary dysfunction can from solifenacin. Macrogol, lubiprostone, and probiotics might be effective in treating constipation. Further research is needed to determine adequate treatment for diaphoresis in PD patients. Multidisciplinary management of motor and non-motor symptoms in PD is the best approach for dysautonomias in PD.