Alpha-adrenoceptor antagonists in neurogenic lower urinary tract dysfunction

Predictive factors for the effect of the α1-D/A adrenoceptor antagonist naftopidil on subjective and objective criteria in patients with neurogenic lower urinary tract dysfunction

OBJECTIVES

• To assess the effect of α1-D/A adrenoceptor antagonist naftopidil on patients with neurogenic lower urinary tract dysfunction (NLUTD) and voiding difficulty. • To explore the effectiveness of naftopidil in these patients by using urodynamic variables, including pressure flow study (PFS), and to find good and simple parameters (International Prostate Symptom Score (IPSS), Post-void residual urine (PVR), and uroflowmetry (UFM) parameters) as substitution of PFS for predicting the effect of naftopidil.

PATIENTS AND METHODS

• The main inclusion and exclusion criteria were, IPSS ≥8, voiding symptoms with IPSS ≥5, IPSS-quality of life (QOL) ≥2, PVR ≥50 mL, and without prostatic enlargement ≥ 20 mL. • After initial assessment, patients were stepwisely administered for 12 weeks with the following: placebo for 2 weeks, naftopidil 25 mg/day for 2 weeks, naftopidil 50 mg/day for 2 weeks, and naftopidil 75 mg/day for 6 weeks. At the end of both placebo and 6 weeks' naftopidil 75 mg/day, their IPSS, UFM, PVR, and PFS were assessed. • A total of 82 Japanese patients (men 40, women 42) with lower urinary tract symptoms complicated by NLUTD, with a mean age of 63.9 years, were included from private or institutional clinics. • The lesions were spinal cord 42, and peripheral nervous system 40. The spinal cord lesions were all lumbar spine (injury or lumbar canal stenosis).

RESULTS

• In all patients, pressure at maximum urinary flow rate (P(det) Q(max) ) in PFS significantly decreased (P < 0.05), and maximum urinary flow rate in UFM significantly increased (P < 0.01). Analysis of data for men and for women also showed a significant decrease in PVR, %PVR, and total IPSS score. • The degree of improvement of voided volume, PVR (%), and IPSS in patients with PVR <300 mL was significantly greater than those in patients with PVR ≥300 mL. • The degree of improvement of P(det) Q(max) in PFS, and IPSS in patients with bladder contractility was significantly greater than that in patients without bladder contractility.

CONCLUSIONS

• α1-D/A adrenoceptor antagonist naftopidil has a significant effect on both symptoms and urodynamic variables of patients of both genders with NLUTD in Japan. • PVR <300 mL and bladder contractility are predictive factors for the efficacy of naftopidil on patients with NLUTD.

Sacral neuromodulation after stabilization of L2-S1 vertebrae with metallic fixation devices: is it feasible?

Sacral neuromodulation is a surgical treatment for voiding difficulties. We report the case of a patient affected by overflow urinary incontinence and reduced bladder sensation subsequent to decompression and stabilization of L2-S1, showing that sacral nerve stimulation can be used in patients with sacral anatomy distortion and metallic fixation system. In these cases, implant is feasible with fluoroscopic guidance and little changes of standard implantation procedure.

Recognition and effective management of autonomic dysreflexia in spinal cord injuries

Autonomic dysreflexia is a potentially life-threatening hypertensive medical emergency that occurs most often in spinal cord-injured individuals with spinal lesions at or above the mid-thoracic spinal cord level. It is a condition that remains poorly recognised outside of spinal cord injury centres, which may result in adverse outcomes including mortality from potentially delayed diagnosis and treatment. Acute autonomic dysreflexia is characterised by severe paroxysmal hypertension associated with throbbing headaches, profuse sweating, nasal stuffiness, flushing of the skin above the level of the lesion, bradycardia, apprehension and anxiety, which is sometimes accompanied by cognitive impairment. The key to effective management is prevention of the condition, by recognition and avoidance of factors that initiate the condition. When it occurs, immediate recognition and reversal of trigger factors along with prompt administration of pharmacological treatment is of paramount importance in order to prevent complications, which include intracranial and retinal haemorrhage, convulsions, cardiac irregularities and death. Promising data from recent animal studies may hold the key to future treatment options.

Effects of different alpha-1 adrenoceptor blockers on proximal urethral function using in vivo isovolumetric pressure changes

The effects of different alpha-1 adrenoceptor blockers on the urethra and the cardiovascular system were evaluated using an in vivo isovolumetric intra-urethral pressure model in New Zealand white rabbits. The urethra of anesthetized male rabbits was cannulated through the bladder and secured at the vesico-urethral junction. The distal side of urethra under the pubic bone was also closed to allow measurement of the intra-urethral pressure. Both the intra-urethral pressure and the femoral arterial pressure were monitored. The effects of five different alpha-1 adrenoceptor blockers on the increases in both the intra-urethral pressure and blood pressure induced by phenylephrine were then examined. The inhibition rate of the alpha-1 adrenoceptor blockers prazosin, bunazosin, terazosin, alfuzosin and tamsulosin on the increase in intra-urethral pressure caused as a result of contraction by phenylephrine was 87.5 +/- 4.5% (mean +/- S.E.), 88.0 +/- 7.2%, 86.2 +/- 6.2%, 81.4 +/- 4.8% and 92.5 +/- 5.0% respectively. The potency ranking of these alpha-1 adrenoceptor blockers was tamsulosin > bunazosin > prazosin > terazosin > alfuzosin. Their inhibition rate of the arterial pressure increase induced by phenylephrine was 81.9 +/- 5.0%, 86.2 +/- 5.9%, 76.0 +/- 6.0%, 63.6 +/- 5.7% and 58.0 +/- 5.2% respectively, with a potency ranking of bunazosin > prazosin > terazosin > alfuzosin > tamsulosin. We therefore conclude that the alpha-1 adrenoceptor blockers bunazosin and prazosin have a more potent action on both the urethra and the vascular system. However, tamsulosin and alfuzosin displayed a marked blockade of the increased urethral pressure induced by phenylephrine, with much less of a blockade of arterial pressure. In the present study, tamsulosin has been shown to be the most sensitive and powerful of the alpha-1 adrenoceptor blockers on urethral smooth muscle.

alpha1-Adrenergic mechanism in diabetic urethral dysfunction in rats

PURPOSE

We investigated the contribution of alpha1-adrenoceptor mechanisms to urethral dysfunction associated with diabetes mellitus (DM) in rats.

MATERIALS AND METHODS

Eight weeks after streptozotocin injection (65 mg/kg intraperitoneally) the effects of DM on urethral relaxation mechanisms were evaluated with subjects under urethane anesthesia by simultaneous recordings of intravesical pressure in isovolumetric conditions and urethral perfusion pressure (UPP).

RESULTS

In diabetic rats the intravesical pressure thresholds for inducing urethral relaxation and the lowest urethral pressure (UPP nadir) during urethral relaxation were significantly higher by 142% and 86%, respectively, than in normal rats, while baseline UPPs were not significantly different. The mean rate of high frequency oscillations of urethral striated muscle in diabetic rats was also significantly lower by 23% than in normal rats. After alpha-bungarotoxin treatment (333 mug/kg intravenously) to eliminate striated muscle sphincter contractions the SD of baseline UPPs was significantly larger by 93% than in normal rats. Intravenous administration of terazosin (0.4 mg/kg), an alpha1-adrenoceptor antagonist, significantly decreased the UPP nadir, intravesical pressure thresholds inducing urethral relaxation and the SD by 41%, 87% and 138%, respectively, in diabetic rats but not in normal rats. In the 2 groups of animals after alpha-bungarotoxin treatment urethral relaxation during a reflex bladder contraction was inhibited by Nomega-nitro-L-arginine (40 mg/kg intravenously), a nitric oxide synthase inhibitor.

CONCLUSIONS

During reflex bladder contractions streptozotocin induced diabetic rats showed smooth and striated muscle dysfunctions of the urethra. The inhibition of alpha1-adrenoceptors, which decreased the UPP nadir and UPP fluctuation, may be useful for treating urethral dysfunction in DM.

Urodynamic effects of alpha1-blocker tamsulosin on voiding dysfunction in patients with neurogenic bladder

BACKGROUND

The therapeutic role of alpha-blockers in the treatment of voiding disorders due to benign prostatic hyperplasia has been extensively examined. To investigate a possible effect of alpha1-blocker on urodynamic voiding parameters in patients with neurogenic bladder, we conducted a clinical trial using tamsulosin.

METHODS

Twenty-four patients (14 men and 10 women) ranging from 24 to 82 years of age (mean age 61 years) with neurogenic bladder were analyzed. Urodynamic studies were performed before and after treatment with 0.4 mg tamsulosin daily for 4 weeks.

RESULTS

On uroflowmetry, the average flow rate (from 4.6 +/- 3.3 to 6.7 +/- 3.0 mL/s, P = 0.04), maximum flow rate (from 9.4 +/- 6.8 to 14.1 +/- 7.0 mL/s, P = 0.016) and residual urine rate (from 46 +/- 29 to 32 +/- 21%, P = 0.02) improved significantly. In patients with detrusor contraction during voiding, detrusor opening pressure and detrusor pressure at maximum flow decreased significantly from 69.0 +/- 36.2 to 49.2 +/- 26.4 cmH2O (P = 0.046) and from 66.7 +/- 34.6 to 53.6 +/- 26.5 cmH2O (P = 0.007), respectively. On the other hand, in patients with detrusor areflexia, vesical opening pressure (from 78.2 +/- 23.4 to 61.6 +/- 25.2 cmH2O), or vesical pressure at maximum flow (from 68.6 +/- 23.2 to 62.9 +/- 25.2 cmH2O) did not change significantly after treatment.

CONCLUSION

Tamsulosin reduces functional urethral resistance during voiding and improves flow rate in patients with neurogenic bladder. It has more beneficial urodynamic effects in patients with detrusor contraction during voiding than in patients with detrusor areflexia.

Tamsulosin: Efficacy and Safety in Patients With Neurogenic Lower Urinary Tract Dysfunction Due to Suprasacral Spinal Cord Injury

PURPOSE

We evaluated the efficacy and safety of tamsulosin in patients with neurogenic lower urinary tract dysfunction secondary to suprasacral spinal cord lesions in a 4-week randomized controlled trial (RCT) followed by a 1-year, open label, long-term study.

MATERIALS AND METHODS

A total of 263 patients were randomized to 4-week double-blind therapy with placebo, or 0.4 or 0.8 mg tamsulosin once daily. Of these, 244 patients completed the RCT, 186 continued long-term tamsulosin therapy (0.4 or 0.8 mg once daily) and 134 completed 1-year treatment. The primary efficacy parameter was maximum urethral pressure (MUP).

RESULTS

Although the mean decrease in MUP at 4 weeks in the RCT did not reach statistical significance over the placebo, it was more pronounced with 0.4 (-12.2 cm H2O or -10%) and 0.8 mg (-9.6 cm H2O or -9%) tamsulosin than placebo (-6.5 cm H2O or -3%). In the long-term study there was a statistically significant mean decrease in MUP (-18.0 cm H2O, p <0.001 or -15%) from baseline to end point. In the long-term study tamsulosin also decreased maximum urethral closure pressure, improved several cystometry parameters related to bladder storage and emptying, and increased to a statistically significantly degree, from baseline to end point, mean voided volume based on the micturition diary. There was statistically significant improvement for the International Prostate Symptom Score Quality of Life, as well as several questions about symptoms related to urinary leakage, and 1 question on bladder emptying and frequency, bother and severity of symptoms of autonomic dysreflexia. Finally, 71% of patients improved according to investigators (44% slightly and 27% much improved). Both doses were effective and well tolerated.

CONCLUSIONS

Long-term tamsulosin treatment (0.4 and 0.8 mg once daily) seems to be effective and well tolerated in patients with neurogenic lower urinary tract dysfunction. The results suggest that it improves bladder storage and emptying, and decreases symptoms of autonomic dysreflexia.

The use of alpha1-adrenoceptor antagonists in lower urinary tract symptoms: beyond benign prostatic hyperplasia

The first empirical use of alpha(1)-adrenoceptor antagonists in urology occurred about 25 years ago in patients with lower urinary tract symptoms (LUTS) suggestive of benign prostatic hyperplasia (BPH), or LUTS/BPH. Today, many randomized, controlled trials have provided evidence for the efficacy and tolerability of alpha(1)-adrenoceptor antagonists in LUTS/BPH, and they are the most frequently used initial treatment option for this cause of LUTS. For many years, alpha(1)-adrenoceptor antagonists have also been used empirically in other types of lower urinary tract dysfunction (LUTD), such as chronic prostatitis/chronic pelvic pain syndrome (CP/CPPS) and neurogenic LUTD (NLUTD). Several investigators have shown that alpha(1)-adrenoceptor antagonists may be useful in patients with CP/CPPS. This was recently confirmed by a 6-week, double-blind, placebo-controlled pilot study evaluating the efficacy and safety of tamsulosin in 58 CP/CPPS patients. Further well-designed and -powered research into the use of alpha(1)-adrenoceptor antagonists in patients with CP/CPPS is currently ongoing. Several small-scale predominantly open-label studies have suggested that alpha(1)-adrenoceptor antagonists may be of benefit in patients with NLUTD. Data from 2 recent large-scale studies with tamsulosin in patients with NLUTD caused by suprasacral spinal cord injury suggest that long-term tamsulosin treatment improves bladder storage and emptying and also reduces symptoms of autonomic dysreflexia. Tamsulosin has also shown promise in ameliorating (early) storage symptoms and urinary retention associated with transurethral microwave thermotherapy, external-beam radiotherapy, and brachytherapy. In BPH patients presenting with the ultimate form of LUTS-acute urinary retention-treatment with tamsulosin before catheter removal results in a higher success rate of catheter-free voiding. Finally, it seems that alpha(1)-adrenoceptor antagonists may reduce the occurrence of urinary retention after (general) surgery. We can therefore conclude that alpha(1)-adrenoceptor antagonists, such as tamsulosin, may be useful for treating men with LUTS beyond BPH.