Background: Non-ambulatory dogs with thoracolumbar spinal cord injuries frequently develop urinary retention due to increased urethral resistance. This is often pharmacologically addressed with Alpha-adrenergic receptor blockers (e.g. prazosin, tamsulosin). The difference in their efficacy is currently unknown. Hypothesis/
Objectives: Our goal was to determine the efficacy of tamsulosin compared to prazosin in managing urinary retention for non-ambulatory dogs with intervertebral disc herniations. We hypothesized that tamsulosin would be better than prazosin regarding the rate of achieving effective bladder expression or voluntary urination, duration of hospitalization, and the subjective ease of bladder expression before discharge. Animals: Client-owned dogs presenting for a T3-L3 myelopathy undergoing a hemilaminectomy for treatment of intervertebral disc extrusion.
Methods: This double-blinded, randomized, positive control clinical trial compared the effectiveness of tamsulosin and prazosin for urinary retention post-hemilaminectomy. The post-operative timeline to reach a small bladder size (measured by ultrasound) after expression and voluntary urination was compared between groups.
Results: Twenty-nine dogs completed the study. Dogs reached effective bladder expression in 2 days (median) in the tamsulosin group, and 1.5 days with prazosin (p=0.44). Effective voluntary urination was achieved in 3.5 days (median) in the tamsulosin group, and 3 days with prazosin (p=0.16). Furthermore, no significance was found between hours to reach effective bladder expression and voluntary urination after starting medications. Conclusions and Clinical Importance: Tamsulosin is clinically comparable to prazosin in treating urinary retention in non-ambulatory dogs post-hemilaminectomy for intervertebral disc extrusion. Dosed once daily, tamsulosin may be a more convenient option for owners.
Learning Objectives:
Manage urinary retention with an Alpha-adrenergic blocker effectively in non-ambulatory dogs post-hemilaminectomy for intervertebral disc herniation
Assess the efficacy of bladder expression in non-ambulatory dogs post-hemilaminectomy after starting an Alpha-adrenergic receptor blocker
Prepare the owner of the timeline for achieving effective voluntary urination in non-ambulatory dogs post-hemilaminectomy after starting treatment
