The treatment of neurogenic orthostatic hypotension with 3,4-DL-threo- dihydroxyphenylserine: A randomized, placebo-controlled, crossover trial

Objective: To study the therapeutic effect and mechanism of action of 3,4-DL-threo-dihydroxyphenylserine (DL-DOPS) in neurogenic orthostatic hypotension. Methods: The blood pressure (BP) response to an orthostatic challenge on DL-DOPS was compared with that of placebo in a randomized, double-blind, placebo-controlled, crossover trial in 10 patients. The mechanism of action of DOPS was studied by measuring forearm vascular resistance and changes in supine and upright plasma DL-DOPS and norepinephrine levels. The effect of DL-DOPS on the quality of life was determined by questionnaire. Results: DL-DOPS increased the supine (p < 0.001) and Upright (p < 0.05) systolic blood pressure (SBP) and diastolic blood pressure (DBP) (both p < 0.01). The peak SBP on DL-DOPS in the supine position occurred 300 minutes after ingestion of the medication. The increase in BP was accompanied by an increase in plasma levels of norepinephrine and DL-DOPS in both the supine and upright positions after DL-DOPS ingestion (p < 0.0001). There was a trend toward improvement in symptoms of orthostatic intolerance. Conclusion: DL-DOPS improved features of neurogenic orthostatic hypotension in patients with central and peripheral autonomic nervous system disease. There was an increase in plasma norepinephrine. No major side effects occurred.