• The hypothesis will be tested by measuring three parameters during prazosin and non-prazosin trials in which ejaculation occurs. [ Time Frame: Unspecified ] [ Designated as safety issue: No ]
  
• 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 ] [ Designated as safety issue: No ]
  
• Subjective parameters: subject perceived efficacy and side effects of the medication and willingness to use the medication at home [ Time Frame: Unspecified ] [ Designated as safety issue: No ]
  

• Secondary outcomes will include the subject's knowledge of AD. [ Time Frame: Unspecified ] [ Designated as safety issue: No ]
  

Drug: Prazosin HCL
See 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.