Effects of carvedilol on human prostate tissue contractility and stromal cell growth pointing to potential clinical implications.

BACKGROUND: Apart from antagonizing ß-adrenoceptors, carvedilol antagonizes vascular α1-adrenoceptors and activates G protein-independent signaling. Even though it is a commonly used antihypertensive and α1-adrenoceptors are essential for the treatment of voiding symptoms in benign prostatic hyperplasia, its actions in the human prostate are still unknown. Here, we examined carvedilol effects on contractions of human prostate tissues, and on stromal cell growth. METHODS: Contractions of prostate tissues from radical prostatectomy were induced by electric field stimulation (EFS) or α1-agonists. Growth-related functions were examined in cultured stromal cells. RESULTS: Concentration-response curves for phenylephrine, methoxamine and noradrenaline were right shifted by carvedilol (0.1-10 µM), around half a magnitude with 100 nM, half to one magnitude with 1 µM, and two magnitudes with 10 µM. Right shifts were reflected by increased EC50 values for agonists, with unchanged Emax values. EFS-induced contractions were reduced by 21-54% with 0.01-1 µM carvedilol, and by 94% by 10 µM. Colony numbers of stromal cells were increased by 500 nM, but reduced by 1-10 µM carvedilol, while all concentrations reduced colony size. Decreases in viability were time-dependent with 0.1-0.3 µM, but complete with 10 µM. Proliferation was slightly increased by 0.1-0.5 µM, but reduced with 1-10 µM. CONCLUSIONS: Carvedilol antagonizes α1-adrenoceptors in the human prostate, starting with concentrations in ranges of known plasma levels. In vitro, effect sizes resemble those of α1-blockers used for the treatment of voiding symptoms, which requires concentrations beyond plasma levels. Bidirectional and dynamic effects on the growth of stromal cells may be attributed to "biased agonism".

Potential side effects of currently available pharmacotherapies in male lower urinary tract symptoms suggestive of benign prostatic hyperplasia.

INTRODUCTION: The drug classes of α1-adrenoceptor antagonists, 5α-reductase inhibitors, and phosphodiesterase type 5 inhibitors are guideline-recommended treatments of lower urinary tract symptoms suggestive of benign prostatic hyperplasia; muscarinic receptor antagonists and ß3-adrenoceptor agonists are also recommended if storage symptoms are insufficiently addressed with one of the other three drug classes. AREAS COVERED: We provide a narrative review (no formalized literature searches performed) of the tolerability of these drug classes with emphasis on the more recently introduced medications, on combination treatment, and on more lately emerging risks. EXPERT OPINION/COMMENTARY: The tolerability profiles are distinct between drug classes but, with few exceptions, similar within a drug class. Within a drug, formulations with longer duration of action tend to have better tolerability. Efficacy gains using combination treatment at least partly come at a cost of lesser tolerability. Greater susceptibility to experience adverse events based on age, comorbidities, and comedications appears conceptually important but remains under-investigated in this therapeutic area.

Several classes of medicines are available to treat male lower urinary tract symptoms that are believed to result from an enlarged prostate. These include α₁-adrenoceptor antagonists (α-blockers), 5α-reductase inhibitors (ARI), and phosphodiesterase type 5 inhibitors (PDEI); muscarinic receptor antagonists and ß₃-adrenoceptor agonists are additionally used in men that have persisting storage symptoms upon treatment with the former three drug classes. Each drug class has a distinct tolerability profile. Within a drug class, medicines with a longer duration of action, either intrinsically or due to specific drug formulations, tend to have better tolerability. Men with greater age, comorbidities, and comedications may be at greater risk of experiencing side effects when medically treating their lower urinary tract symptoms. While combination of members of multiple drug classes may increase efficacy, this often comes at the price of experiencing more side effects. The relative benefit/risk ratio needs to be individually analyzed in each patient.

Association of diabetes, hypertension, and their combination with basal symptoms and treatment responses in overactive bladder patients.

Introduction: Pelvic hypoperfusion caused by atherosclerosis has been proposed as a cause of lower urinary tract dysfunction including overactive bladder syndrome (OAB). Limited data indicate that OAB patients with concomitant diabetes or hypertension, known risk factors of atherosclerosis, may exhibit greater baseline OAB symptoms and slightly smaller therapeutic responses to treatment, but the impact of a combined presence of diabetes and hypertension has not been reported. Therefore, we have explored whether the combined presence of both comorbidities is associated with greater baseline OAB symptoms than that of either comorbidity alone. Secondary questions were exploration of the impact of either comorbidity on baseline symptoms, and of the impact of either comorbidity alone and their combination on therapeutic responses. Methods: Data from two non-interventional studies applying treatment with propiverine ER 30 or 45 mg/d for 12 weeks were analyzed. Results: Number of urgency episodes in the combination group was greater than with each comorbidity alone. The impact of comorbidities on baseline intensity of incontinence, frequency or nocturia or Patient Perception of Bladder Condition was less consistent or absent. Either comorbidity alone was associated with a smaller % improvement of symptoms, and their combination had a greater effect than either alone. However, all attenuations associated with comorbidity were small relative to the overall improvement. Conclusions: We conclude that comorbidities of diabetes and hypertension have detectable effects on OAB symptoms and treatment responses, but the small magnitude of these alterations does not justify changing existing paradigms for the clinical management of OAB.

What Are Realistic Expectations to Become Free of Overactive Bladder Symptoms? Experience from Non-interventional Studies with Propiverine.

INTRODUCTION: Unmet expectations are a major cause of perceived treatment failure and discontinuation of treatment. To enable evidence-based counselling of patients on realistic expectations, we determined the chance of patients with overactive bladder becoming free of a given symptom upon treatment with a muscarinic antagonist in a non-interventional setting. METHODS: Two non-interventional studies included 1335 and 745 patients, respectively, who received 30 or 45 mg q.d. propiverine ER for 12 weeks. They were monitored for becoming free of urgency, urinary incontinence, frequency, or nocturia. Analyses were also performed in subgroups defined by basal symptom severity, age, and gender. Categorical data are shown as a percentage of the respective population. Continuous data are expressed as means or as median depending on whether the variability was considered to exhibit a normal distribution. RESULTS: The probability of becoming symptom-free was largest for incontinence and frequency (about 50%), but lesser for urgency (about 20%) and nocturia (about 10%). Greater basal severity of a symptom reduced the chance to become free of that symptom upon treatment, but the chance to become free of incontinence and frequency was still considerable. Age and gender had only minor if any effects on the chance of becoming symptom-free. These findings are in line with those of a limited number of randomized controlled trials. CONCLUSION: These data provide an evidence base for the counselling of patients with overactive bladder on realistic expectations of treatment outcomes. We propose that realistic expectations can lead to greater long-term adherence.

Unmet expectations are a major reason why patients with overactive bladder syndrome discontinue treatment. To enable evidence-based counselling of patients on realistic expectations, we have determined the chance that patients with overactive bladder become free of urgency, incontinence, voiding frequency, and nocturia. Two non-interventional studies included 1335 and 745 patients, respectively, who received 30 or 45 mg q.d. propiverine ER for 12 weeks. Analyses were also performed in subgroups defined by basal symptom severity, age, and gender. The probability of becoming symptom-free was largest for incontinence and voiding frequency (about 50%), but lesser for urgency and nocturia (about 20%). Greater basal severity of a symptom reduced the chance to become free of that symptom upon treatment, but the chance to become free of incontinence and frequency was still considerable. Age and gender had only minor if any effects on the chance of becoming symptom-free. These data provide an evidence base for the counselling of patients with overactive bladder on realistic expectations of treatment outcomes. We propose that realistic expectations can lead to greater long-term adherence.

Normalization of organ bath contraction data for tissue specimen size: does one approach fit all?

Organ bath experiments are a key technology to assess contractility of smooth muscle. Despite efforts to standardize tissue specimen sizes, they vary to a certain degree. As it appears obvious that a larger piece of tissue should develop greater force, most investigators normalize contraction data for specimen size. However, they lack agreement which parameter should be used as denominator for normalization. A pre-planned analysis of data from a recent study was used to compare denominators used for normalization, i.e., weight, length, and cross-sectional area. To increase robustness, we compared force with denominator in correlation analysis and also coefficient of variation with different denominators. This was done concomitantly with urinary bladder strips and aortic rings and with multiple contractile stimuli. Our urinary bladder data show that normalization for strip weight yielded the tightest but still only moderate correlation (e.g., r2 = 0.3582 for peak carbachol responses based on 188 strips). In aorta, correlations were even weaker (e.g., r2 = 0.0511 for plateau phenylephrine responses normalized for weight based on 200 rings). Normalization for strip size is less effective in reducing data variability than previously assumed; the normalization denominator of choice must be identified separately for each preparation.

Cognitive and mood side effects of lower urinary tract medication.

Introduction: Muscarinic receptor antagonists, 5α-reductase inhibitors and α1-adrenoceptor antagonists are frequently used drug classes for the treatment of lower urinary tract symptoms including those of overactive bladder syndrome and benign prostatic enlargement/benign prostatic obstruction. Areas covered: The authors review the evidence for adverse effects of these drug classes on cognitive function, mood and other functions of the central nervous system and discuss such effects against the evidence for mechanistic plausibility. Expert opinion: Muscarinic antagonists carry a risk for impaired cognition and other brain functions that differs quantitatively between compounds, being highest with oral formulations of oxybutynin. 5□-Reductase inhibitors can cause depressive symptoms even at low doses and starting several months after discontinuation of treatment. The evidence for α1-adrenoceptor antagonists and specifically tamsulosin to cause dementia is controversial and lacks mechanistic plausibility. We recommend that physicians treating patients with lower urinary tract symptoms carefully monitor mental status prior to prescribing and periodically thereafter.