Pharmacological Interventions
Two studies have examined pharmacological interventions (midodrine and methylprednisolone) for the treatment of OH. While midodrine hydrochloride in acute OH has also been studied in case report format (Barber et al. 2000; Mukand et al. 2001), these studies did not meet SCIRE inclusion criteria. Several other pharmacological agents have been studied in the chronic SCI population, including fludrocortisone, dihydroergotamine, ephedrine, L-threo-3,4-dihydroxyphenylserine (LDOPS), nitro-L-arginine methyl ester (L-NAME), although little evidence exists regarding their use for OH in chronic SCI (refer to SCIRE Orthostatic Hypotension rehabilitation evidence chapter).
Discusion
Two studies examined the impact of pharmacological management on OH during acute SCI. Phillips et al. (2014) conducted a RCT examining the effectiveness of midodrine for OH in10 SCI patients, the majority of which had acute injuries (6.5-11 weeks after injury). This study did also include two patients with chronic SCI who were 144-324 weeks after injury. Patients were subjected to a tilt-table procedure in which they were progressively tilted from supine position to 30°, 45°, and 60° angles. This procedure was conducted over two days, during which time the SCI patients were randomly assigned to receive 10 mg of midodrine orally, or no treatment (baseline measure). Improvement in orthostatic tolerance was observed in 59% of patients who received midodrine; this was a significant improvement compared to those who received no treatment (p<0.01). A more recent prospective controlled trial by Krstacic et al. (2016), examined the effects of methylprednisolone on heart rate in an SCI population. However, this study found no significant differences between groups over a treatment period of 23 hours. Heart rate variability was monitored via an electrocardiogram holter monitor.
Conclusion
There is level 2 evidence (from one RCT crossover: Phillips et al. 2014) that midodrine hydrochloride leads to improved orthostatic tolerance in acute SCI patients.
There is level 2 evidence (from one PCT: Krstacic et al. 2016) that methylprednisolone may have no effects on heart rate variability in SCI populations.
