Abstract | BACKGROUND: METHODS AND RESULTS: We determined the effect of oral administration of the synthetic amino acid L-threo-3,4-dihydroxyphenylserine (L-DOPS), which is decarboxylated to NE by the enzyme L- aromatic amino acid decarboxylase (L-AADC) in neural and nonneural tissue, on blood pressure and orthostatic tolerance in 19 patients with severe NOH (8 with pure autonomic failure and 11 with multiple-system atrophy). A single-blind dose-titration study determined the most appropriate dose for each patient. Patients were then enrolled in a double-blind, placebo-controlled, crossover trial. L-DOPS significantly raised mean blood pressure both supine (from 101+/-4 to 141+/-5 mm Hg) and standing (from 60+/-4 to 100+/-6 mm Hg) for several hours and improved orthostatic tolerance in all patients. After L-DOPS, blood pressure increases were closely associated with increases in plasma NE levels. Oral administration of carbidopa, which inhibits L-AADC outside the blood-brain barrier, blunted both the increase in plasma NE and the pressor response to L-DOPS in all patients CONCLUSIONS: Acute administration of L-DOPS increases blood pressure and improves orthostatic tolerance in patients with NOH. The pressor effect results from conversion of L-DOPS to NE outside the central nervous system.
|
Authors | Horacio Kaufmann, Daniela Saadia, Andrei Voustianiouk, David S Goldstein, Courtney Holmes, Melvin D Yahr, Rachel Nardin, Roy Freeman |
Journal | Circulation
(Circulation)
Vol. 108
Issue 6
Pg. 724-8
(Aug 12 2003)
ISSN: 1524-4539 [Electronic] United States |
PMID | 12885750
(Publication Type: Clinical Trial, Controlled Clinical Trial, Journal Article, Research Support, Non-U.S. Gov't, Research Support, U.S. Gov't, P.H.S.)
|
Chemical References |
- Antiparkinson Agents
- Aromatic-L-Amino-Acid Decarboxylases
- Droxidopa
- Carbidopa
- Norepinephrine
|
Topics |
- Administration, Oral
- Aged
- Antiparkinson Agents
(adverse effects, pharmacokinetics, therapeutic use)
- Aromatic-L-Amino-Acid Decarboxylases
(drug effects, metabolism)
- Blood Pressure
(drug effects)
- Carbidopa
(pharmacology)
- Cross-Over Studies
- Double-Blind Method
- Droxidopa
(adverse effects, pharmacokinetics, therapeutic use)
- Female
- Hemodynamics
(drug effects)
- Humans
- Hypotension, Orthostatic
(drug therapy, etiology, physiopathology)
- Male
- Middle Aged
- Neurodegenerative Diseases
(complications)
- Norepinephrine
(biosynthesis, blood, physiology)
- Posture
- Single-Blind Method
- Treatment Outcome
|