Study design: Clinical trial.
Objectives: Individuals with spinal cord injury (SCI) above T6 experience impaired descending cortical control of the autonomic nervous system, which predisposes them to hypotension. However, treatment of hypotension is uncommon in the SCI population because there are few safe and effective pharmacological options available. The primary aim of this investigation was to test the efficacy of a single dose of midodrine (10 mg), compared with placebo, to increase and normalize systolic blood pressure (SBP) between 110 and 120 mmHg during cognitive testing in hypotensive individuals with SCI. Secondary aims were to determine the effects of midodrine on cerebral blood flow velocity (CBFv) and global cognitive function.
Setting: United States clinical research laboratory.
Methods: Forty-one healthy hypotensive individuals with chronic (≥1-year post injury) SCI participated in this 2-day study. Seated SBP, CBFv, and cognitive performance were monitored before and after administration of identical encapsulated tablets, containing either midodrine or placebo.
Results: Compared with placebo, midodrine increased SBP (4 ± 13 vs. 18 ± 24 mmHg, respectively; p < 0.05); however, responses varied widely with midodrine (-15.7 to +68.6 mmHg). Further, the proportion of SBP recordings within the normotensive range did not improve during cognitive testing with midodrine compared with placebo. Although higher SBP was associated with higher CBFv (p = 0.02), global cognitive function was not improved with midodrine.
Conclusions: The findings indicate that midodrine increases SBP and may be beneficial in some hypotensive patients with SCI; however, large heterogeneity of responses to midodrine suggests careful monitoring of patients following administration.
Clinical trials registration: NCT02307565.