A clinical experience with dantrolene sodium for external urinary sphincter hypertonicity in spinal cord injured patients.

Significant bladder residual urine is secondary to pelvic floor skeletal muscle hypertonicity in some spinal cord injury patients with suprasacral or mixed lesions. Fifteen patients with residual urine volumes greater than 150 cc were treated with dantrolene sodium because of its ability to decrease skeletal muscle contractibility. All of the patients had urethral closure pressures greater than 100 cm. water. Of the 15 patients 8 benefited from dantrolene sodium therapy and were maintained on external condom urinary drainage. Five of these 8 patients required up to 600 mg. dantrolene sodium daily to affect this result. The residual urine volume decreased to less than 100 cc and the post-therapy decrease in urethral pressure averaged 77 cm. water (49 per cent). The patients in the failure group (residual urine greater than 150 cc) had an average decrease in urethral pressure of 21 cm. water (16 per cent). Detrusor hyporeflexia possibly contributed to the failure rate. In summary, dantrolene sodium seems to be beneficial in some patients with external urinary sphincter hypertonicity. However, it will not supplant external sphincterotomy in the more complete male spinal cord injury patient in whom reflex incontinence is of minimal concern. Dantrolene sodium could be an ideal treatment of patients with incomplete neurologic lesions in whom continence might be preserved. The drug will have to be effective at low doses to obviate the major side effect of over-all muscle weakness.