Objective:

We investigated the effect of levodopa on blood pressure and baroreflex function in individuals with Parkinson disease (PD) with (PD^+OH) and without neurogenic OH (PD^-OH).

Background:

The association between levodopa and orthostatic hypotension (OH) remains controversial. 

Design/Methods:

We performed a prospective randomized cross-over study with autonomic testing performed ON and OFF levodopa. The primary outcome was the change in systolic blood pressure (SBP) from supine to 70-degree-tilt at 3 minutes (ΔSBP-3’). Secondary outcomes included indices of baroreflex function and blood pressure and heart rate measured at regular intervals during tilt.

Results:

We enrolled 40 individuals with PD (21 PD^+OH, 19 PD^-OH, mean age (SD)=73.2 years (7.9), 13 females (32.5%)). There was no difference in age, sex, disease duration and severity between PD^+OH and PD^-OH. Mean difference in ΔSBP-3’ ON versus OFF levodopa in the whole study population was -3.20 mmHg [-7.36 – 0.96] (p=0.14). Mean difference in ΔSBP-3’was -2.14mmHg [-7.55 – 3,28] (p=0.45) in PD^+OH and -5.14mmHg [-11.63 – 1.35] (p=0.14) in PD^-OH. Mean difference in ΔSBP ON levodopa was greater compared to testing OFF levodopa at 7 and 10 minutes (-7.52mmHg [-11.89 – -3.15], p=0.002, and -7.82mmHg [-14.02 – -1.67], p=0.02 respectively). Levodopa was associated with lower blood pressure in the supine position and during 70-degree-tilt in both PD^+OH and PD^-OH. Levodopa was associated with cardiovascular noradrenergic baroreflex impairment.

Conclusions: