Although levodopa is considered the gold standard for Parkinson's disease 
therapy, prolonged use of this drug can result in motor complications such as a 
'wearing-off' phenomenon. This outcome is seen in a significant number of 
patients with Parkinson's disease taking levodopa and, in some cases, is 
observed only a few hours after intake of the last dose of levodopa. Patients 
experiencing the wearing-off period may present with sensory, autonomic, 
psychiatric and motor fluctuations. Although infrequent, shortness of breath is 
an important non-motor wearing-off symptom experienced by patients with 
Parkinson's disease. In addition to being a symptom induced by wearing off, 
other causes of shortness of breath include pulmonary diseases, coronary artery 
disease and anxiety. Thus, it is important to identify the cause of shortness of 
breath to ensure that the appropriate treatment is initiated. We report here on 
a patient with Parkinson's disease who was taking levodopa and developed both 
shortness of breath and hyperventilation during wearing-off periods. He 
underwent extensive pulmonary and cardiac investigations that were unremarkable. 
His shortness of breath was determined to be a wearing-off phenomenon and his 
condition improved with the addition of a catechol-O-methyltransferase inhibitor 
(entacapone).