Combination antimuscarinics and α-blockers for benign prostatic hyperplasia

A survey of the FAERS database concerning the adverse event profiles of α1-adrenoreceptor blockers for lower urinary tract symptoms

PURPOSE

Current guidelines recommend α1-adrenoreceptor blockers (A1Bs) for treating lower urinary tract symptoms suggestive of benign prostatic hyperplasia, but their adverse effects can be problematic. In this study, reports submitted to the US Food and Drug Administration Adverse Event Reporting System (FAERS) between 1997 and 2011 were reviewed to assess the safety profiles of A1Bs.

METHODS

After deleting duplicated submissions and revising arbitrary drug names, reports involving A1Bs for male patients were analyzed. Data mining algorisms were used for the quantitative detection of signals, where a signal represents an association between a drug and an adverse event or a drug-associated adverse event, including the proportional reporting ratio, reporting odds ratio, information component given by a Bayesian confidence propagation neural network, and empirical Bayes geometric mean.

RESULTS

The total number of reports used was 1,260,182. Signal scores suggested the associations of alfuzosin, doxazosin, tamsulosin, and terazosin with dizziness/vertigo, orthostatic hypotension, erectile dysfunction, ejaculation dysfunction (EjD), thirst/dry mouth, and constipation; however, reports on naftopidil, silodosin, and urapidil were not enough to compare with the other 4 A1Bs. Signal scores for EjD were higher for tamsulosin, and those for dizziness/vertigo were lower for doxazosin than for the other 3 drugs.

CONCLUSIONS

Tamsulosin-associated EjD, which was found in clinical studies, was reproduced in this analysis with markedly higher signal scores, and these results strongly suggest the necessity of well-organized clinical studies on A1B-associated adverse events.

The role of antimuscarinics in the management of men with symptoms of overactive bladder associated with concomitant bladder outlet obstruction: an update

CONTEXT

This review focuses on the contemporary role of antimuscarinics in the management of men with symptoms of bladder outlet obstruction (BOO) and concomitant overactive bladder (OAB). Safety issues of antimuscarinics in this subpopulation of men are also reviewed.

OBJECTIVE

We reviewed the current literature and performed an analysis of the efficacy, suitability, and the safety of antimuscarinics in this subpopulation of men.

EVIDENCE ACQUISITION

We performed a systematic search of Medline/PubMed, Embase, Scopus, and the Cochrane Database of Systematic Reviews for relevant articles published between 1990 and September 2010, restricted to studies in humans published in English. In addition, published abstracts presented at the annual meetings of the European Association of Urology, the American Urological Association, and the International Continence Society in the last decade (2000-2010) were hand-searched and evaluated. Each article's title and abstract were reviewed for their appropriateness and relevance to the use of antimuscarinics in patients with BOO and concomitant OAB. Relevant articles were fully reviewed and included in the final data acquisition.

EVIDENCE SYNTHESIS

Treatment options include combination treatment with α-blockers and antimuscarinics, sequential use of α-blockers and antimuscarinics, monotherapy with antimuscarinics, and a combination of antimuscarinics and 5α-reductase inhibitors. The sequential use of α-blockers and antimuscarinics seems to be the most appropriate approach, and the use of antimuscarinics and α-blockers appears generally to be safe and efficacious. Data are insufficient for a possible stratification of patients for a specific sequence of the drugs reviewed.

CONCLUSIONS

This review infers that the existing data confirm the safety of antimuscarinics administered for the treatment of these patients. The efficacy of antimuscarinics has been proven in different trials regarding different storage symptom end points, but not all end points regarding OAB reached significance. All the reported trials are of short duration (4-12 wk) and include only men with low postvoid residual urine volumes at baseline (<200ml). Overall, the addition of an antimuscarinic to the treatment of a patient with BOO and concomitant OAB seems to offer an amelioration of the symptoms and a moderate improvement in quality of life.

Silodosin: an orally active selective α1-adrenoceptor antagonist for benign prostatic hyperplasia

α1-adrenoceptor antagonists play a central role in the treatment of uncomplicated symptomatic benign prostatic hyperplasia, frequently in combination with the 5-α-reductase inhibitors such as finasteride and dutasteride. Clinically useful examples include alfuzosin, doxazosin, tamsulosin and terazosin. These can be subdivided into nonselective (doxazosin and terazosin) and uroselective (alfuzosin and tamsulosin) agents. In general, these agents appear to be equieffective. However, they can be distinguished on the basis of their adverse event profiles. Such adverse events include those due to their vasodilatory effects (dizziness, orthostatic hypotension and rhinitis), genitourinary effects (ejaculatory dysfunction) and nonspecific effects (e.g., asthenia, malaise and gastrointestinal upset). A new α1A-adrenoceptor antagonist, silodosin, has recently been approved. In most ways, it is similar to tamsulosin in its pharmacodynamic effects in vitro and in vivo (in both animals and humans). Limited clinical trial data have shown silodosin to significantly improve lower urinary tract symptoms associated with benign prostatic hyperplasia and quality of life, with effects sustainable for at least 1 year. Its adverse-event profile reflects that seen with other uroselective α-adrenoceptor antagonists with the exception of a relatively high-incidence rate of ejaculatory dysfunction (22 vs 2% with tamsulosin and 28 vs 1% with placebo). This article reviews the preclinical and clinical data concerning silodosin and introduces the reader to this new drug for the treatment of benign prostatic hyperplasia.