MSA is characterized by early development of autonomic dysfunction. Also, development of nausea, vomiting, hypotension, and profuse perspiration during acute levodopa challenge are common in parkinsonian patients even if pre-treated with domperidone to prevent the acute dopaminergic effects of levodopa.

Nine (10.1%) out of the 89 patients [women:33(37%)] developed symptoms of levodopa intolerance. Four out the seven patients with intolerance (57.4%) and five out the 68 patients from the control (without levodopa intolerance) group (5.9%) received a diagnosis of MSA (p =0.0). Overall sensitivity and specificity of the presence of symptoms of levodopa intolerance to predict the diagnosis of MSA were 50% and 95.5%respectively.

Development of levodopa intolerance during an acute levodopa challenge increases the probability of diagnosing MSA, but the absence of levodopa intolerance during the acute levodopa challenge could be less helpful in excluding a diagnosis of MSA.