Silodosin for benign prostatic hyperplasia

OBJECTIVE

To review the pharmacology, pharmacokinetics, clinical trials, and safety of silodosin, a recently approved alpha(1A)-adrenergic receptor (AR) antagonist for benign prostatic hyperplasia (BPH).

DATA SOURCES

English-only articles obtained from MEDLINE (1966-October 2009) using the search terms silodosin and KMD-3213 were reviewed. In addition, a search of International Pharmaceutical Abstracts (1970-October 2009) was conducted.

STUDY SELECTION AND DATA EXTRACTION

Available English-language articles were reviewed, as well as abstracts from available non-English articles.

DATA SYNTHESIS

Silodosin reduces urinary symptoms associated with BPH in as little as 1 day after initiation. The largest clinical trial conducted to date demonstrated a decrease in International Prostate Symptom Score of -6.4 +/- 6.63 points compared to -3.5 +/- 5.84 in patients receiving placebo (p < 0.0001). Silodosin also improved urinary flow rates by approximately 2.8 +/- 3.44 mL/sec, which is comparable to other alpha(1)-AR antagonists. The usual dose of silodosin is 8 mg once daily and should be reduced to 4 mg for patients with moderate renal dysfunction. Use is contraindicated in patients with severe renal and hepatic impairment or taking strong CYP3A4 inhibitors. In clinical trials, the most prevalent adverse effects were ejaculatory disturbances, occurring in approximately 28% of patients, although only 2.8% of patients discontinued treatment due to this adverse effect. Preliminary data suggest that, similar to other third-generation alpha(1A)-AR antagonists, silodosin has little potential to cause significant cardiovascular adverse effects such as orthostatic hypotension or syncope. To confirm these findings, long-term studies are still needed, especially in patients taking antihypertensive agents and in those with a history of intolerance to other alpha(1)-AR antagonists.

CONCLUSIONS

Silodosin was approved by the Food and Drug Administration in 2008. Long-term studies demonstrating improvement in clinically important outcomes of BPH have yet to be published. In addition, pharmacoeconomic analyses would assist in defining its current place in therapy. Until this information is available, silodosin may be best reserved as an alternative to other second- and third-generation alpha(1)-AR antagonists.

Does Preoperative Topical Antimicrobial Scrub Reduce Positive Surgical Site Culture Rates in Men Undergoing Artificial Urinary Sphincter Placement?

PURPOSE

We determined if the incidence of a perioperative surgical site-positive culture was reduced by a 5-day topical antimicrobial scrub before implantation of an artificial urinary sphincter.

MATERIALS AND METHODS

A single surgeon prospective cohort study was conducted of 100 consecutive artificial urinary sphincter implants placed between May 2003 and November 2005. We compared 50 men who performed preoperative topical antimicrobial scrub with 4% chlorhexidine to the abdominal site and perineal site with 50 men who used their normal hygiene (soap and water). All received povidone-iodine skin disinfection before incision, and bacterial cultures of the abdominal and perineal sites were collected immediately after skin disinfection and after artificial urinary sphincter implantation. Baseline comparisons between groups were done with the Wilcoxon rank sum and Fisher exact tests. Predictors of positive culture were identified using multivariate logistic regression analysis.

RESULTS

The causes of incontinence were radical prostatectomy (90), radiation therapy (8) and transurethral resection of the prostate (2). There were no baseline differences between the groups including age, diabetes or previous urethral surgery. Overall 140 of the 400 cultures were positive with only 37% of the positive cultures (52 of 140) observed with topical antimicrobial scrub. For the perineal site the only factor affecting preoperative culture status was topical antimicrobial scrub (OR 0.23, p = 0.003). A positive postoperative culture was predicted by a positive preoperative perineal (OR 4.61, p = 0.003) and abdominal culture (OR 3.80, p = 0.013).

CONCLUSIONS

Preoperative topical antimicrobial scrub resulted in a 4-fold reduction in preoperative perineal colonization rate and overall reduction in positive surgical site cultures. Given the low cost, safety and efficacy, topical antimicrobial scrub should be considered before artificial urinary sphincter placement.

Patients With pT1 Renal Cell Carcinoma Who Die From Disease After Nephrectomy May Have Unrecognized Renal Sinus Fat Invasion

Prior studies suggest that the renal sinus permits early tumor spread in otherwise localized renal cell carcinoma (RCC) tumors. We hypothesized that renal sinus fat invasion may be unrecognized in pT1 patients who subsequently die from RCC. Between 1985 and 2002, we identified 577 patients who underwent radical nephrectomy for localized pT1 clear cell RCC as reviewed by a single urologic pathologist (J.C.C.). Among these patients, 49 died from RCC including 33 who had their original nephrectomy specimen stored in formalin. These specimens were then resectioned with thin cuts of the renal sinus and reviewed by the same pathologist. For comparison, 33 patients who did not die from RCC (controls) also had their original nephrectomy specimen resectioned. Among the 33 patients who died from seemingly localized RCC, 14 (42%) had previously unrecognized renal sinus fat invasion compared with 2 (6%) of the controls (P<0.001). In addition, 19 (58%) patients who died from RCC had renal sinus small vein (microscopic venous) invasion, a pathologic feature not currently incorporated into the TNM staging system for RCC. This feature was present in 7 (21%) of the controls (P=0.003). In total, 22 (67%) patients who died from RCC had unrecognized renal sinus fat or small vein invasion compared with 7 (21%) of the controls (P<0.001). We conclude that renal sinus fat invasion is an important adverse pathologic feature that is clearly underreported in the literature. Appropriate assessment of nephrectomy specimens should include proper sampling of the renal sinus even for seemingly localized tumors.

Tandem transcorporal artificial urinary sphincter cuff salvage technique: surgical description and results

PURPOSE

Complications associated with placement of artificial urinary sphincter may make reoperation necessary. We present a surgical description and outcome data for tandem transcorporal artificial urinary sphincter salvage technique for nonmechanical artificial urinary sphincter failure.

MATERIALS AND METHODS

A retrospective analysis from July 2002 to December 2005 identified 198 consecutive men who underwent artificial urinary sphincter placement by a single surgeon (DSE) for postoperative stress urinary incontinence. Tandem transcorporal salvage artificial urinary sphincter surgery was performed in 18 patients with 1 (10 of 18) or both (8 of 18) cuffs placed transcorporally. Etiology of previous artificial urinary sphincter failure leading to the insertion of both cuffs in the transcorporal position included 3 infections, 2 erosions, 2 impending erosions, and 1 failed male sling. A self-administered standardized questionnaire was used to assess continence and quality of life outcomes.

RESULTS

At a median followup of 26 months (IQR 14 to 30), pad use decreased from a median of 5.0 (IQR 3.5 to 5) to 2.0 (IQR 1 to 3) (p<0.001). Two patients experienced explantation of the device (1 erosion, 1 infection) without reimplantation and, thus, were excluded from outcome analysis. Eleven (69%) required 2 or fewer pads daily, and 5 (31%) required 3 pads daily. Eleven (69%) reported being very or extremely improved. Of the 5 patients reporting some or no improvement 4 were also on androgen deprivation therapy, suggesting that the transcorporal technique may be less durable in this group of patients.

CONCLUSIONS

Tandem transcorporal artificial urinary sphincter placement is an effective approach to salvage cases with a high risk of repeat erosion or infection after failed artificial urinary sphincter placement.