Table 2.

Phase 2 clinical studies with L-DOPS and DL-DOPS in patients with neurogenic OH

Study	Subjects (N)	Active agent	Design	Results
Hoeldtke et al, 1984 [97]	6 (2 PAF and 4 autonomic diabetic neuropathy)	DL-DOPS	Open label crossover study using a single dose of DL-DOPS (600 or 800 mg) and single dose of placebo in separate days.	No change in supine or upright BP after DL-DOPS.
Kaufmann et al, 1991 [98]	6 (2 PAF; 4 MSA)	L-DOPS	Open label dose titration study followed by 2 days of open label administration (700–1000 mg/day)	L-DOPS increased supine BP in MSA and PAF, and standing BP only in MSA.
Freeman et al, 1999 [99]	10 (6 MSA; 4 PAF)	DL-DOPS	Randomized, double-blind, placebo-controlled, crossover study using a single dose of 1000 mg of DL-DOPS and single dose of placebo	DL-DOPS significantly increased supine and upright BP.
Mathias et al, 2001 [100]	32 (26 MSA; 6 PAF)	L-DOPS	Open label incremental study (4 weeks) followed by a 6-week maintenance study (100–300 mg twice/day)	L-DOPS significantly reduced the fall in systolic BP upon standing and the symptoms of OH.
Kaufmann et al, 2003 [57]	19 (11 MSA; 8 PAF)	L-DOPS	Single blind dose titration study followed by a 3-day double blind, placebo-controlled, crossover trial.	L-DOPS significantly increased supine and standing BP for several hours and improved symptoms of OH. After L-DOPS, BP increases were associated with increases in plasma NE levels.