The ability of the alpha-1
adrenoceptor antagonist,
prazosin, to reduce the severity and duration of episodes of
autonomic dysreflexia was studied in cervical and high thoracic
spinal cord injury patients with documented episodes of
autonomic dysreflexia. Sixteen patients participated in a double blind parallel group study comparing
prazosin 3 mg b.d. with placebo given for 2 weeks. Both groups were matched for age, sex and baseline severity of
autonomic dysreflexia episodes.
Prazosin was well tolerated and did not produce a significant lowering of resting blood pressure. Compared to baseline measurements, patients allocated to
prazosin therapy were found to have fewer severe episodes of
autonomic dysreflexia and during these episodes to have significant reductions in average rise in systolic and diastolic blood pressure, symptom duration and requirement for acute
antihypertensive medication. The severity of
headache during individual
autonomic dysreflexia episodes was also diminished with
prazosin therapy. No symptom parameter was significantly altered by placebo
therapy. It is concluded that
prazosin is superior to placebo in the prophylactic management of
autonomic dysreflexia and that these findings are consistent with suggestions that alpha-1
adrenoceptors play an important role in the pathogenesis of this syndrome.