Effect of levodopa on postural blood pressure changes in Parkinson disease: a randomized crossover study.

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

Methods: We performed a prospective randomized crossover study with autonomic testing performed ON and OFF levodopa. The primary outcome was the change in systolic blood pressure (SBP) from supine to 70° tilt at 3 min (ΔSBP-3'). Secondary outcomes included indices of baroreflex function and blood pressure and heart rate during tilt.

Results: We enrolled 40 individuals with PD (21 PD^+OH, 19 PD^-OH), mean age (SD) 73.2 years (7.9), 13 women (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 to 0.96] (p = 0.14). Mean difference in ΔSBP-3' was - 2.14 mmHg [- 7.55 to 3.28] (p = 0.45) in PD^+OH and - 5.14 mmHg [- 11.63 to 1.35] (p = 0.14) in PD^-OH. Mean difference in ΔSBP ON versus OFF levodopa was greater at 7 and 10 min (- 7.52 mmHg [- 11.89 to - 3.15], p = 0.002, and - 7.82 mmHg [- 14.02 to - 1.67], p = 0.02 respectively). Levodopa was associated with lower absolute values of blood pressure in both PD^+OH and PD^-OH and cardiovascular noradrenergic baroreflex impairment.

Conclusion: Levodopa decreases blood pressure in both PD with and without autonomic failure, but it does not cause a greater fall in blood pressure from supine to standing at 3 min. Levodopa-induced baroreflex sympathetic noradrenergic impairment may contribute to lower blood pressure. Lower standing blood pressure with levodopa may increase the risks of fall and syncope.