Midodrine hydrochloride and L-threo-3,4-dihydroxy-phenylserine preserve cerebral blood flow in hemodialysis patients with orthostatic hypotension.

Orthostatic hypotension (OH) after hemodialysis (HD) is a serious complication, as it causes various neurological symptoms and even ischemic brain damage. The aim of the present study was to evaluate the effects of antihypotensive agents, midodrine hydrochloride (MID) and L-threo-3,4-dihydroxyphenylserine (L-DOPS), on OH after HD. We measured systolic blood pressure (SBP) and cerebral blood flow velocity in the middle cerebral artery (MCVm, by transcranial Doppler sonography), in patients with OH during a 5-min 60-degree head-up tilt test at both before and after 4-week treatment with MID at 4 mg/day (N = 6) or L-DOPS at 400 mg/day (N = 7). Both MID and L-DOPS did not significantly protect against falls in systolic BP (SBP) after passive head-up tilt. However, a significant improvement was achieved in MCVm-decrement in the MID group at 3 min and the L-DOPS group at 0, 1 and 3 min during head-up tilt. Although MID and L-DOPS did not prevent OH after HD in HD patients, both agents preserved cerebral blood flow during orthostasis in HD patients with OH.