Orthostatic Responses to Anticholinesterase Inhibition in Persons with SCI

• Published in: Clinical autonomic research 2015-04, Vol.25 (3), p.179-187
• Main Authors: Wecht, Jill M., Cirnigliaro, Christopher M., Azarelo, Frank, Bauman, William A., Kirshblum, Steven C.
• Format: Article
• Language: English
• ISSN: 0959-9851; 1619-1560
• DOI: 10.1007/s10286-015-0272-3

Acetylcholine (Ach) is the pre-synaptic neurotransmitter of the sympathetic nervous system. Increased pre-synaptic Ach may augment post-synaptic release of norepinephrine thereby increasing systemic blood pressure (BP). The primary objective of this investigation was to determine the hemodynamic effect of pyridostigmine bromide (PYRIDO: 60 mg), an Ach inhibitor (AchI), compared to no-drug (NO-D) during head-up tilt (HUT) in individuals with spinal cord injury (SCI). Secondarily we aimed to determine the effects of PYRIDO compared to NO-D on symptoms of orthostatic intolerance (OI) and adverse event reporting (AE). Ten individuals with SCI (C4–C7) were studied on 2 occasions: visit 1) NO-D and visit 2) PYRIDO. On each visit subjects underwent a progressive HUT maneuver to 15°, 25°, 35° for 5 minutes at each angle and 45 minutes at 45°. Supine and orthostatic heart rate (HR), systolic and diastolic BP (SBP & DBP) were monitored and symptoms of OI and AE recorded. Supine hemodynamics did not differ between the trials. The significant fall in SBP during the NO-D trial was diminished with PYRIDO and five subjects had an increased DBP during HUT with PYRIDO compared to the NO-D trial. Individuals that responded to PYRIDO with an increase in orthostatic BP had significantly lower resting HR than non-responders (p