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Updated: Oct 21, 2025
Induction and Assessment of Levodopa-induced Dyskinesias in a Rat Model of Parkinson's Disease
Published on: October 14, 2021
Biphasic (Subtherapeutic) Levodopa-Induced Respiratory Dysfunction in Parkinson Disease
Veerle A van de Wetering-van Dongen1, Alberto J Espay1, Luca Marsili1
1Department of Rehabilitation (VAvdW-vD, MJN), Radboud University Medical Center, Donders Center for Brain, Cognition and Behavior, Nijmegen, the Netherlands; Department of Neurology (AJE, LM, AS), UC Gardner Neuroscience Institute, Gardner Center for Parkinson's Disease and Movement Disorders, University of Cincinnati, OH; and Department of Neurology (STH, BRB), Radboud University Medical Center, Donders Institute for Brain, Cognition and Behaviour, Center of Expertise for Parkinson and Movement Disorders, Nijmegen, the Netherlands.
Objective:
To evaluate 3 cases illustrating a rarely recognized phenotype of Parkinson disease (PD), namely, biphasic levodopa-induced respiratory dysfunction manifesting as dyspnea.
Methods:
To appreciate the nature of the fluctuations of respiratory function in response to levodopa, we measured changes in respiratory muscle control before and after the best therapeutic response to levodopa in 3 PD patients with fluctuating dyspnea.
Results:
Episodes of breathlessness were accompanied by shallow tachypnea and reduced respiratory muscle control, as measured by maximal expiratory pressure, peak cough flow, and forced expiratory volume in 1 second.
Conclusions:
The spectrum of respiratory dysfunction in PD includes a biphasic reduced respiratory muscle control accompanying periods when the effect of levodopa is subtherapeutic. This biphasic levodopa-related complication represents a rarely recognized nonmotor phenomenon in PD. Management requires increasing the levodopa dose, shortening the interdose interval, or implementing a program of continuous dopaminergic stimulation.
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