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Prazosin Vibrostimulation Autonomic Dysreflexia and Spinal Cord Injury Study

This study has been completed.
Information provided by (Responsible Party):
University of British Columbia Identifier:
First received: September 13, 2005
Last updated: March 1, 2017
Last verified: March 2017
Sexuality is a high rehabilitative priority for persons following a spinal cord injury (SCI). Sexual acts can lead to autonomic dysreflexia (AD), dangerous consequences such as a sudden increase in blood pressure, severe headache, sweating above the level of the lesion and low heart rate to name a few. Ejaculation in men can provoke these significant symptoms and therefore men and women may refrain from a sexual life and biological parenthood. Adalat is the most common antihypertensive used in fertility clinics to reduce the incidence of AD. It dramatically reduces blood pressure and, therefore, results in side effects such as dizziness, fatigue and weakness. The investigators hypothesize that Minipress® (prazosin HCL), a blood pressure medication, which has a slower and less abrupt suppressive effect on blood pressure, would be a safe, effective and more appropriate medication for use in the outpatient sperm retrieval clinic and potentially for private use.

Condition Intervention
Autonomic Dysreflexia
Drug: Prazosin HCL

Study Type: Interventional
Study Design: Allocation: Randomized
Intervention Model: Crossover Assignment
Masking: Participant, Investigator
Primary Purpose: Prevention
Official Title: Prophylactic Value of Prazosin in Reducing the Objective and Subjective Measures of Autonomic Dysreflexia Provoked by Ejaculation in Men With Spinal Cord Injury

Resource links provided by NLM:

Further study details as provided by University of British Columbia:

Primary Outcome Measures:
  • The hypothesis will be tested by measuring three parameters during prazosin and non-prazosin trials in which ejaculation occurs. [ Time Frame: Unspecified ]
  • Objective parameters: absolute beat-to-beat BP, differences between systolic and diastolic BP readings, heart rate variability, heart rate and ECG readings (looking for irregular rhythms) and visible signs of AD experienced by the subject [ Time Frame: Unspecified ]
  • Subjective parameters: subject perceived efficacy and side effects of the medication and willingness to use the medication at home [ Time Frame: Unspecified ]

Secondary Outcome Measures:
  • Secondary outcomes will include the subject's knowledge of AD. [ Time Frame: Unspecified ]

Enrollment: 7
Study Start Date: December 2004
Study Completion Date: July 28, 2011
Primary Completion Date: July 28, 2011 (Final data collection date for primary outcome measure)
Intervention Details:
    Drug: Prazosin HCL
    See Detailed Description
Detailed Description:

The consequences of sexual activity in the spinal cord injured (SCI) population include responses beyond the voluntary control of the person with SCI such as bladder and bowel issues, spasms and autonomic dysreflexia (AD). Currently we are looking at predictive measurements for AD during ejaculation in a controlled setting. Immediate-release Nifedipine (Adalat), a well-known medication used for the treatment of AD is the most commonly prescribed prophylactic antihypertensive used in sperm retrieval and urological procedures. Nifedipine has rapid onset (minutes) and dramatically lowers blood pressure for periods of up to five hours and results in dizziness, fatigue and weakness. As a sperm retrieval center not equipped for hypotensive resuscitation measures, we have refrained from using Nifedipine prior to procedures in hypotensive SCI men at risk for AD.

Our objective is to study the prophylactic capacity of a lesser prescribed antihypertensive medication Prazosin on its ability to reduce the objective and subjective measures of autonomic dysreflexia in order to assess its immediate potential for home use. Prazosin is an alpha-adrenergic blocker and has a slower and less abrupt suppressive effect on blood pressure. We hypothesize that it will reduce AD signs and symptoms, reduce the severity of cardiovascular changes, and improve client comfort without reduction in safety. Having 8 male subjects as their own controls, we plan to examine the objective (beat to beat blood pressure, EKG and visible body signs) and subjective (patient's symptomatic report) parameters of AD provoked by vibrostimulation and ejaculation on and off Minipress (Prazosin HCL). Statistical analysis will be done on three independent observations:

  1. absolute blood pressure values and reduction in abnormal heart rhythms
  2. signs and symptoms of AD
  3. client confidence to undergo ejaculation

We will correlate objective parameters with the subjective findings to see if these observations can be predictive in determining the predictability and severity of AD and the effectiveness of Prazosin as prophylactic AD medication in an outpatient clinic or a private home setting during sexual activities.


Ages Eligible for Study:   18 Years to 55 Years   (Adult)
Sexes Eligible for Study:   Male
Accepts Healthy Volunteers:   Yes

Inclusion Criteria:

  • Male with spinal cord injured above level T6 of greater than one year's duration
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Please refer to this study by its identifier: NCT00175682

Canada, British Columbia
Vancouver General Hospital, BC Centre for Sexual Medicine
Vancouver, British Columbia, Canada
Sponsors and Collaborators
University of British Columbia
Principal Investigator: Stacy Elliott, MD University of British Columbia
  More Information

Responsible Party: University of British Columbia Identifier: NCT00175682     History of Changes
Other Study ID Numbers: C04-0343
Study First Received: September 13, 2005
Last Updated: March 1, 2017

Keywords provided by University of British Columbia:
Autonomic Dysreflexia

Additional relevant MeSH terms:
Spinal Cord Injuries
Autonomic Dysreflexia
Spinal Cord Diseases
Central Nervous System Diseases
Nervous System Diseases
Trauma, Nervous System
Wounds and Injuries
Autonomic Nervous System Diseases
Antihypertensive Agents
Adrenergic alpha-1 Receptor Antagonists
Adrenergic alpha-Antagonists
Adrenergic Antagonists
Adrenergic Agents
Neurotransmitter Agents
Molecular Mechanisms of Pharmacological Action
Physiological Effects of Drugs processed this record on April 24, 2017