Results

14 patients received placebo infusion on the first study day and levodopa on the second day, while 15 received the converse. All data were collected as intended with the exception of a standing pulse for one subject and post-infusion standing blood pressure for one patient after levodopa infusion and for one patient after placebo infusion. Baseline clinical characteristics are summarized in Table 1.

No significant difference was found between vital sign parameters during levodopa versus placebo infusions (table 2, figure 1). Standing increased P and DBP, and the magnitude of this change increased somewhat from earlier to later in the day, but none of these changes differed between levodopa and placebo. The largest absolute orthostatic increases in P, both of which were found on the post-infusion measurements, were 11.7 bpm on the placebo day and 12.3 bpm on the levodopa day. The largest absolute orthostatic increases in DBP, also found on the post-infusion measurements, were 7.4 mmHg in the placebo group and 2.0 mmHg in the levodopa group (p = 0.20). For the differences between levodopa and placebo for all vital sign parameters (supine P/SBP/DBP, standing P/SBP/DBP, orthostatic change in P/SBP/DBP), paired p values ranged between 0.16 (for supine SBP) and 0.92 (for standing SBP). Additionally, no significant difference was found for adverse effect scales (table 3).