Combined oral therapy with sildenafil and doxazosin for the treatment of non-organic erectile dysfunction refractory to sildenafil monotherapy

Study of phosphodiesterase 5 inhibitors and α-adrenoceptor antagonists used alone or in combination for the treatment of lower urinary tract symptoms due to benign prostatic hyperplasia

INTRODUCTION

This study sought to compare the improvement in lower urinary tract symptoms (LUTS) and complications of phosphodiesterase type 5 inhibitors (PDE5i) and alpha-blockers (Abs) in combination or alone among males with benign prostatic hyperplasia (BPH).

EVIDENCE ACQUISITION

We searched the PubMed, Embase, and Cochrane Library databases to identify all studied variables, including lower urinary tract symptoms (LUTS), BPH, Abs, and PDE5i and performed comparisons between combination treatment and single treatments as primary endpoints. Efficacy analysis including the International Prostate Symptom Score (IPSS), quality of life (QOL), maximum urinary flow rate (Qmax), postvoiding residual volume (PVR), and International Index of Erectile Function erectile function domain (IIEF-EF) score. Complications were also recorded. In addition, the secondary endpoint was a comparison of the efficacy and complications between the two single treatments.

EVIDENCE SYNTHESIS

Nineteen studies involving 2,426 patients met the inclusion criteria. The data synthesized from these studies indicated that the combination treatment is better in efficiency than PDE5i or Abs alone in including IPSS (P<0.00001 in PDE5i; P=0.01 in Abs), QOL (P<0.00001 in PDE5i; P<0.00001 in Abs), Qmax (P<0.00001 in PDE5i; P<0.00001 in Abs), PVR (P=0.04 in PDE5i; P<0.00001 in Abs), and IIEF-EF (P<0.00001 in PDE5i; P<0.00001 in Abs). Regarding complications, only headache (P<0.00001), dyspepsia (P=0.01), and flushing (P=0.04) were more frequent in individuals undergoing the combination treatment.

CONCLUSIONS

Combination treatment is more effective than PDE5i or Abs alone, though the side effects are not significantly different.

Non-invasive Management Options for Erectile Dysfunction When a Phosphodiesterase Type 5 Inhibitor Fails

Phosphodiesterase type 5 inhibitors (PDE5Is) are the drug of choice for medical management of erectile dysfunction (ED). On-demand PDE5Is have an overall efficacy of 60-70% for ED; 30-35% of patients fail to respond to a PDE5I, and 30-50% of non-responders can be salvaged with detailed counseling on proper use and physician follow-up to ensure that the patient has been prescribed an appropriate and full PDE5I clinical trial. True non-responders may be offered intracavernosal injections of erectogenic drugs, intraurethral alprostadil, or surgical insertion of a penile prosthesis. Such options are not discreet and are associated with more adverse effects than PDE5Is. Thus patients may request additional non-invasive medical management options. This review describes published literature on patients who failed to respond to an on-demand PDE5I regimen and were treated with a non-invasive PDEI-based regimen, including switching from one PDE5I to another; increasing the dose of PDE5I above the labeled dosage range; using two PDE5Is concurrently; using a daily PDE5I regimen; or combining a PDE5I with a testosterone supplement, α-adrenergic antagonist, intraurethral or intracavernosal alprostadil, vacuum erection device, or low-intensity shock wave therapy. The limitations of published clinical trials do not allow for sufficient evidence to recommend one option over another. Therefore, in PDE5I-refractory patients, the choice of a specific next step should be individualized based on the preference of the patient and his sexual partner, the advantages and disadvantages of the various options, the concurrent medical illnesses and medications of the patient, and the patient's response to treatment.

The efficacy of PDE5 inhibitors alone or in combination with alpha-blockers for the treatment of erectile dysfunction and lower urinary tract symptoms due to benign prostatic hyperplasia: a systematic review and meta-analysis

INTRODUCTION

Erectile dysfunction (ED) and lower urinary tract symptoms (LUTS) are both highly prevalent in aging men. Alpha-blockers and PDE-5 inhibitors are widely used for the treatment of LUTS/benign prostatic hyperplasia (BPH) and ED.

AIM

The purpose of this meta-analysis was to evaluate the efficacy of phosphodiesterase type 5 (PDE5) inhibitors alone or in combination with alpha-blockers for the treatment of ED and LUTS.

METHODS

The databases MEDLINE, EMBASE, PubMed, the Cochrane Controlled Trial Register of Controlled Trials, and the Chinese Biological Medical Database were searched to identify randomized controlled trials that referred to the use of a combination of PDE5 inhibitors and alpha-blockers for the treatment of ED and LUTS associated with BPH. A systematic review and meta-analysis was conducted.

MAIN OUTCOME MEASURES

International Prostate Symptom Score (IPSS), the maximum flow rate (Qmax), and International Index of Erectile Function-Erectile Function (IIEF-EF) domain score were used in this meta-analysis.

RESULTS

Seven publications involving 515 patients were included in the meta-analysis. In the analysis, we found significantly improved IIEF, IPSS, and Qmax values in the combination use group compared with the use of PDE5 inhibitors alone (P = 0.04, 0.004, 0.007, respectively).

CONCLUSIONS

The combined use of PDE5 inhibitors and alpha-blockers results in additive favorable effects in men with ED and LUTS suggestive of BPH compared with PDE5 inhibitor monotherapy. The alpha-blockers may enhance the efficacy of the PDE5 inhibitors, which is beneficial for the treatment of ED and LUTS.

A comparative randomized prospective study to evaluate efficacy and safety of combination of tamsulosin and tadalafil vs. tamsulosin or tadalafil alone in patients with lower urinary tract symptoms due to benign prostatic hyperplasia

INTRODUCTION

Lower urinary tract symptoms (LUTS) associated with benign prostatic hyperplasia (BPH) and erectile dysfunction are common disorders of advancing age.

AIM

To evaluate the efficacy and safety of tamsulosin and tadalafil in patients with LUTS due to BPH.

METHODS

In this prospective randomized study, 133 men complaining of LUTS due to BPH were included. Forty-five patients received tamsulosin 0.4 mg/day alone (Group A), 44 patients received tadalafil 10 mg/day (Group B), and combination therapy (tamsulosin and tadalafil both) was instituted in 44 patients (Group C). After a 2-week medication free run-in period, they were evaluated for International Prostatic Symptom Score (IPSS), International Index of Erectile Function score (IIEF5), quality of life (IPSS QoL), maximum urinary flow rate (Qmax), post-void residual urine (PVR) volume, and safety parameters before and at 3 months of treatment.

MAIN OUTCOME MEASURES

There were primary (IPSS, IPSS QoL index, Qmax, and PVR) and secondary (erectile function [EF] domain scores from IIEF5) efficacy end points. Safety assessment included laboratory tests and patient's reporting of adverse event.

RESULTS

A significant improvement in IPSS score was observed in all the 3 groups A, B, and C (-50.90%, P < 0.05; -33.50%, P < 0.05; and -53.90%, P < 0.05, respectively). IIEF5 score increased significantly in these three groups (+39.28%, P < 0.05; +45.96%, P < 0.05; and +60.23%, P < 0.05, respectively). A significant increase in Qmax and decrease in PVR were also observed (33.99%, P < 0.05; 29.78%, P < 0.05; and 37.04%, P < 0.05) and (-60.90%, P < 0.05; -49.45%, P < 0.05; and -62.97%, P < 0.05, respectively). The QoL scores improved significantly (-73.35%, P < 0.05; -70.26%, P < 0.05; and -79.65%, P < 0.05, respectively). Side effects were dyspepsia, heartburn, headache, flushing, myalgia, and backache. Adverse effect dropout was 3.7%. No participant experienced any severe or serious adverse events.

CONCLUSIONS

In patients with LUTS due to BPH, tamsulosin and tadalafil alone or in combination cause a significant improvement in patients with LUTS. Their EF also improves with these medications. The improvement is better with combination therapy compared with single agent alone.

Effect of patient-optimized doses of tamsulosin on erectile function in men with erectile dysfunction and lower urinary tract symptoms

PURPOSE

To investigate the relationship of improvement in erectile function (EF) with improvement in lower urinary tract symptoms (LUTS) and to assess the contribution of tamsulosin dose to the improvement of EF apart from the indirect influence of LUTS improvement in men with LUTS and erectile dysfunction (ED).

MATERIALS AND METHODS

Fifty patients received tamsulosin 0.2 mg/d for the first 4 weeks and were subsequently divided into two groups by patient-reported outcomes. Nonescalators were maintained starting dose and escalators increased to 0.4 mg for the remaining 8 weeks. International Prostatic Symptom Score (IPSS) and International Index of Erectile Function (IIEF-5), and underwent uroflowmetry were evaluated at baseline, and weeks 4 and 12.

RESULTS

LUTS parameters were significantly improved in both groups but insignificant between the 2 groups. The degree of the improvement in the total IPSS and in the voiding, storage, and quality of life (QoL) subscores were significantly correlated with the degree of the improvement in EF; this was especially prominent in patients successfully treated LUTS. The escalators experienced a significantly greater increase in IIEF-5 scores than did the nonescalators (3.3 vs. 1.5).

CONCLUSIONS

Dose escalation provided similar LUTS improvement in patients with refractory to starting dose. The improvements of LUTS were correlated with the improvement of EF. The increase in the IIEF-5 score was significantly higher in escalators. These findings imply that tamsulosin may contribute to the improvement in EF through the improvement of LUTS and QoL and direct relaxation of the corpus cavernosum in a dose-dependent fashion.

Cardiovascular Parameter Changes in Patients With Erectile Dysfunction Using Pde-5 Inhibitors: A Study With Sildenafil and Vardenafil

Sildenafil is the most prescribed oral agent for patients with erectile dysfunction (ED). Vardenafil is a new phosphodiesterase type 5 (Pde-5) inhibitor that was approved by the US Food and Drug Administration last year to treat patients with ED of various causes. Both of these Pde-5 inhibitors have vasodilating properties and effects on blood pressure (BP), and like nitrates, they work through the nitric oxide cyclic guanosine monophosphate pathway. The aim of this study was to investigate the influence of these Pde-5 inhibitors on BP and heart rate (HR) in normotensive men with ED by a crossover comparison. Thirty-five patients with ED were enrolled to evaluate and compare the effect of sildenafil (50 mg) and vardenafil (10 mg) on BP and HR. At the screening (baseline [B]) visit, sitting systolic blood pressure (B-SBP), diastolic blood pressure (B-DBP), and HR were measured. We performed a multiple administration for both drugs and, therefore, multiple measurements of BP and HR changes, 3 doses a week, on alternate days, late in the afternoon, and on an empty stomach. B-SBP, B-DBP, and HR were recorded before each 50-mg sildenafil dosing and after 30, 60, 120, and 240 minutes. Data were averaged over the 4 time points and compared with the baseline values obtained before each dosing. After a 3-week wash-out period, patients were crossed over to vardenafil (10 mg) with the same study design. After administration of both drugs, we observed a statistically significant decrease of BP and an increase of HR. On average, sildenafil caused a decrease of SBP ranging from 5.1 +/- 3.9 mm Hg during the first dosing to 4.7 +/- 4.2 mm Hg during the third dosing, DBP ranged from 4.4 +/- 4.9 to 4 +/- 4.1 mm Hg, and HR increased 1.8 +/- 2.0 bpm (first dose) and 1.2 +/- 0.9 bpm (third dose). With vardenafil, we recorded a greater variation for SBP and DBP. SBP decreased from 8.02 +/- 8.0 mm Hg during the first dosing to 5.4 +/- 5.5 mm Hg during the third dosing, whereas DBP decreased from 6.6 +/- 7.2 to 5.0 +/- 5.3 mm Hg, respectively. Recorded HR showed an increase of 3.1 +/- 3.2 bpm (first dose) and 2.4 +/- 2.3 bpm (third dose). After the first vardenafil administration, we recorded fainting episodes in 3 patients because of a decrease in BP greater than 20 mm Hg. Two of the patients were in therapy with doxazosin for benign prostatic hyperplasia (BPH). Cardiovascular response was not significantly different after the first dose between the 2 treatments. Vardenafil demonstrated clinically significant differences (fainting) with respect to sildenafil only during the first doses. We suggest that before starting therapies with Pde-5 inhibitors, particularly with the newer ones, that baseline cardiovascular parameters are measured and monitored, especially during the first dose, because of the presence of a "first dose effect." Moreover, it is necessary to pay particular attention to those patients in treatment with other drugs that could have a synergistic hypotensive effect as a result of vasodilation potentiation.

The effects of the combined use of a PDE5 inhibitor and medications for hypertension, lower urinary tract symptoms and dyslipidemia on corporal tissue tone

ED is closely associated with its comorbidities (hypertension, dyslipidemia and lower urinary tract symptoms (LUTS)). Therefore, several drugs have been prescribed simultaneously with PDE5 inhibitors. If a specific medication for ED comorbidities has enhancing effects on PDE5 inhibitors, it offers alternative combination therapy in nonresponders to monotherapy with PDE5 inhibitors and allows clinicians to treat ED and its comorbidities simultaneously. To establish theoretical basis of choosing an appropriate medication for ED and concomitant disease, we examined the effects combining a PDE5 inhibitor with representative drugs for hypertension, dyslipidemia and LUTS on relaxing the corpus cavernosum of rabbits using the organ-bath technique. The effect of mirodenafil on relaxing phenylephrine-induced cavernosal contractions was significantly enhanced by the presence of 10(-4) M losartan, 10(-6) M nifedipine, 10(-6) M amlodipine, 10(-7) M doxazosin and 10(-9) M tamsulosin (P<0.05). The maximum relaxation effects were 47.2±3.8%, 57.6±2.6%, 64.0±3.7%, 76.1±5.7% and 71.7±5.4%, respectively. Enalapril and simvastatin had no enhancing effects. The relaxation induced by sodium nitroprusside alone (39.0±4.0%) was significantly enhanced in the presence of the 10(-4) M losartan (66.0±6.0%, P<0.05). Tetraethylammonium (1 mM) significantly inhibited the enhancement effects of tamsulosin and doxazosin on mirodenafil-induced relaxation (doxazosin: 76.1±5.7% vs 45.3±2.3%; tamsulosin: 71.7±5.4% vs 48.1±3.5%). On the basis of these findings, losartan seemed to induce synergistic effects through an interaction with nitric oxide. In addition, K(+) channel activation could be one of the mechanisms for the synergistic effect of combining mirodenafil with doxazosin or tamsulosin. We believe that the combination of a PDE5 inhibitor with losartan, nifedipine, amlodipine, doxazosin or tamsulosin could be a pharmacologic strategy for simultaneously treating ED and its comorbidities and increasing response rates to PDE5 inhibitors.

Non-invasive management of primary phosphodiesterase type 5 inhibitor failure in patients with erectile dysfunction

Phosphodiesterase type 5 inhibitors (PDE5-i) have become first line therapy for the treatment of erectile dysfunction. Most initial prescriptions for PDE5-i are by primary care practitioners. Urologists must now routinely manage the patient who has failed initial therapy with PDE5-i. Lifestyle modifications can be of benefit to patients. Patient education and optimization of the PDE5-i can result in a successful response. Interestingly, there are reports of up to 60% salvage after changing the PDE5-i utilized. Daily PDE5-i have shown benefit, and treatment of hypogonadism can enhance response to PDE5-i. We review the management of PDE5-i failures with emphasis on noninvasive approaches to gaining improved erectile response to these medications. An algorithm based on the reviewed strategies is proposed to guide clinicians in the treatment of erectile dysfunction.

An open, comparative, multicentre clinical study of combined oral therapy with sildenafil and doxazosin GITS for treating Chinese patients with erectile dysfunction and lower urinary tract symptoms secondary to benign prostatic hyperplasia

This study sought to investigate the clinical efficacy and safety of combined oral therapy with sildenafil and doxazosin GITS compared to sildenafil monotherapy in treating Chinese patients with erectile dysfunction (ED) and lower urinary tract symptoms secondary to benign prostatic hyperplasia (BPH/LUTS). The trial was conducted in hospitals in Beijing, Shanghai, Changsha, Wuhan and Guangzhou, five major cities in China. A total of 250 patients diagnosed with ED and BPH/LUTS aged 50-75 years, and who had International Index of Erection Function-5 (IIEF-5) scores ≤21 and International Prostate Symptom Score (IPSS) ≥10 points, were enrolled and randomly divided into Group A (168 cases; doxazosin GITS 4 mg once daily plus sildenafil 25-100 mg on demand) and Group B (82 cases; sildenafil 25-100 mg on demand). Efficacies were evaluated by IIEF-5 and IPSS scores and a quality of life (QoL) questionnaire, and adverse effects were evaluated during the treatment period. There were no statistically significant differences in mean age, and IIEF-5, IPSS and QoL scores pre-treatment between the two groups. After treatment, IIEF-5, IPSS and QoL scores were significantly improved in Group A, while only IIEF-5 scores were significantly improved in Group B compared with pre-treatment. There were no significant differences in side effects between the two groups. The results indicated that combined therapy with sildenafil and doxazosin GITS for the treatment of ED and BPH/LUTS is safe and effective compared to sildenafil monotherapy.

Combination therapy for erectile dysfunction: an update review

The introduction of oral phosphodiesterase-5 inhibitors (PDE5Is) in the late 1990s and early 2000s revolutionized the field of sexual medicine and PDE5Is are currently first-line monotherapy for erectile dysfunction (ED). However, a significant proportion of patients with complex ED will be therapeutic non-responders to PDE5I monotherapy. Combination therapy has recently been adopted for more refractory cases of ED, but a critical evaluation of current combination therapies is lacking. A thorough PubMed and Cochrane Library search was conducted focusing on the effectiveness of combination therapies for ED in therapeutic non-responders to PDE5I therapy. Journal articles spanning the time period between January 1990 and December 2010 were reviewed. Criteria included all pertinent review articles, randomized controlled trials, cohort studies and retrospective analyses. References from retrieved articles were also manually scanned for additional relevant publications. Published combination therapies include PDE5I plus vacuum erectile device (VED), intraurethral medication, intracavernosal injection (ICI), androgen supplement, α-blocker or miscellaneous combinations. Based on this review, some of these combination treatments appeared to be quite effective in preliminary testing. Caution must be advised, however, as the majority of combination therapy articles in the last decade have numerous limitations including study biases and small subject size. Regardless of limitations, present combination therapy research provides a solid foundation for future studies in complex ED management.

Safety of sildenafil citrate: review of 67 double-blind placebo-controlled trials and the postmarketing safety database

AIM

To review special safety topics associated with sildenafil and to document the tolerability of 50- and 100-mg doses, overall and by age, in men with erectile dysfunction (ED).

METHODS

Data were collated from 67 double-blind placebo-controlled (DBPC) trials (> 14,000 men) conducted by the manufacturer and from the manufacturer's postmarketing safety database (39,277 patients). The DBPC data were stratified by dose, starting dose and age (> or = 65 and > or = 75 years). Special safety topics included cardiovascular risk, priapism, non-arteritic anterior ischaemic optic neuropathy (NAION), impaired renal and hepatic function, drug interactions (i.e. nitrates, cytochrome P3A4 inhibitors, other ED therapies and alpha-blockers) and incorrect use.

RESULTS

Sildenafil was well tolerated at a dose of 50 or 100 mg in men with ED, overall, in those aged > or = 65 years, and in those aged > or = 75 years. Analyses of the databases did not reveal any causal link between sildenafil and cardiovascular events, or any new safety risks relating to cardiovascular events, priapism, NAION, hearing loss or drug interactions. In the small number of men with moderate impairment of renal function or hepatic function who were treated with sildenafil in DBPC trials, the safety profile was similar to that in men with no impairment of renal or hepatic function. Overdose with sildenafil was rare in the ED population. No new safety issues, emerging trends or adverse reactions were identified in conjunction with overdose, dependence, abuse or misuse.

CONCLUSION

This collated review confirms generally the good tolerability and established safety profile of sildenafil 50 and 100 mg in men with ED and reveals no new safety issues.

Common approach to managing lower urinary tract symptoms and erectile dysfunction

The present paper serves as a review of the associations between lower urinary tract symptoms (LUTS) and erectile dysfunction (ED), with a focus on common and combined pathways for treatment. LUTS and ED are common conditions seen in general urologic practice. Research has started to establish epidemiologic and pathophysiologic links between the two conditions and a strong association confirmed across multiple studies. Men seeking care for one condition should always be interviewed for complaints of the other condition. Proposed common pathways include alpha-1 adrenergic receptor imbalance, Rho-kinase overactivity, endothelial cell dysfunction and atherosclerosis-induced ischemia. Medical therapy has replaced surgery as the first-line treatment for LUTS in most patients, with the incorporation of alpha-adrenergic receptor antagonists (alpha-ARAs) and 5-alpha-reductase inhibitors (5-ARIs) into everyday practice. Treatment with alpha-ARAs contributes to some improvement in ED, whereas use of 5-ARIs results in worsened sexual function in some patients. Phosphodiesterase-5 (PDE-5) inhibitors have revolutionized the treatment of ED with a simple oral regimen, and new insights demonstrate a benefit of combined use of PDE-5 inhibitors and alpha-ARAs. The mechanisms of action of these medications support these observed benefits, and they are being studied in the basic science and clinical settings. In addition, novel mechanisms for therapy have been proposed based on clinical and research observations. The minimally invasive and surgical treatments for LUTS are known to have adverse effects on ejaculatory function, while their effects on erectile function are still debated. Much remains to be investigated, but it is clear that the associations between LUTS and ED lay the foundation for future therapies and possible preventative strategies.

Combination of alfuzosin and tadalafil exerts in vitro an additive relaxant effect on human corpus cavernosum

INTRODUCTION

Phosphodiesterase type 5 (PDE5) inhibitors, such as tadalafil, are a first-line treatment for erectile dysfunction (ED). Nevertheless, some patients do not respond to this treatment. Clinical data suggest that the addition of alpha1-adrenoceptor blocker, such as alfuzosin, commonly prescribed for lower urinary tract symptoms suggestive of benign prostatic hyperplasia, may be of benefit. Aim. Evaluation of the effect of alfuzosin, tadalafil or the combination of both on human corpus cavernosum.

METHODS

Human cavernosal tissues were obtained from 10 patients undergoing penile surgery. Strips contractility was studied in organ baths. Concentration-response curves to tadalafil were generated on norepinephrine (NE, 1-10 microM)-precontracted strips in the presence of alfuzosin or vehicle. Frequency-response curves (FRC) to electrical field stimulation (EFS, 0-64 Hz, 3 ms, 10 seconds, 300 mA) were generated in the presence of vehicle, alfuzosin, tadalafil, or both drugs combined. EFS (20 Hz, 1 ms, 10 seconds, 300 mM)-induced nitrergic relaxation on NE-precontracted strips was studied in the presence of vehicle, alfuzosin, tadalafil, or both drugs combined.

MAIN OUTCOME MEASURES

Functional measurement of cavernosal smooth muscle relaxation in the presence of tadalafil and alfuzosin.

RESULTS

The relaxation induced by tadalafil (10(-10) to 10(-5) M) on precontracted strips was enhanced by alfuzosin at both 10(-8) and 10(-7) M. The combination of alfuzosin (3.10(-8) M) and tadalafil (10(-7) M) was more efficient to inhibit FRC-induced contractions than each compound alone. The combination of tadalafil (10(-6) M) and alfuzosin (10(-8) M) increased the relaxation induced by EFS and its effect was greater than tadalafil alone. In addition, the combination of tadalafil (10(-6) M) and alfuzosin (10(-7) M) prolonged EFS-induced relaxation to a greater extent than each compound alone.

CONCLUSIONS

In vitro, the combination of alfuzosin and tadalafil is more efficient than each compound alone to relax adrenergic tone or to enhance nitrergic relaxation of the human corpus cavernosum. Such a combination deserves further investigation in placebo-controlled studies to evaluate its benefit in ED patients who are not sufficiently improved by PDE5 inhibitors.

Erectile dysfunction as the presenting symptom of a pheochromocytoma

We report the case of a 59-year-old man with a pheochromocytoma in which erectile dysfunction was the main symptom. Erectile function was related to the amount of noradrenaline secreted by the tumor, as was determined when recurrence of the malignancy was diagnosed twice. Erectile function could be restored by lowering the level of noradrenaline excretion, either by removal of the noradrenaline-producing tumor or by treatment with doxazosin. By stimulating alpha-1-adrenoceptors, high levels of noradrenaline are likely to result in excessive contraction of the corpus cavernosum and penile vessels and, thereby, cause erectile dysfunction.

Medical treatment of benign prostatic hyperplasia

Pharmaceutical preparations are commonly used for benign prostate hyperplasia. This article reviews the current understanding of the natural history of the condition and the literature regarding medical treatment.

Combination of alfuzosin and sildenafil is superior to monotherapy in treating lower urinary tract symptoms and erectile dysfunction

OBJECTIVES

This pilot study was undertaken to assess the efficacy and safety of the alpha(1)-blocker alfuzosin 10mg once daily (OD), the PDE-5 inhibitor sildenafil 25mg OD, and the combination of both on lower urinary tract symptoms (LUTS) suggestive of benign prostatic hyperplasia (BPH) and erectile dysfunction (ED).

MATERIAL AND METHODS

Men aged 50-76 yr with previously untreated LUTS and ED were randomized to receive alfuzosin (n=20), sildenafil (n=21), or the combination of both (n=21) for 12 wk. Changes from baseline in International Prostate Symptom Score (IPSS), voiding diary, maximum urinary flow rate (Qmax), postvoid residual urine (PVRU) volume, and erectile function domain of the International Index of Erectile Function (IIEF) were assessed at week 12.

RESULTS

Improvement of IPSS was significant with the three treatments but greatest with the combination (-24.1%) compared with alfuzosin (-15.6%) and sildenafil (-11.8%) [corrected] alone (p<0.03). Frequency, nocturia, PVR, and Qmax were significantly improved with alfuzosin only and the combination. Improvement in IIEF was slight with alfuzosin (16.7%), marked with sildenafil (49.7%), and greatest with the combination (58.6%). Likewise, increases in the frequency of penetration (Q3) and of maintained erection (Q4) were greater with the combination therapy (65.2% and 68.2%, respectively) than with sildenafil (41.7% and 59.1%, respectively) and alfuzosin (27.3% and 33.3%, respectively) alone. All three treatments were well tolerated.

CONCLUSIONS

In this pilot study, the combination of alfuzosin 10 mg OD and sildenafil 25 mg OD is safe and more effective than monotherapy with either agent to improve both voiding and sexual dysfunction in men with LUTS suggestive of BPH.

Management of sildenafil treatment failures

PURPOSE OF REVIEW

Although oral type 5 phosphodiesterase inhibitors are considered as first-line therapy for the majority of causes of erectile dysfunction, because of their high efficacy, ease of use, and acceptable safety profile, there are some who fail to respond, mainly because of end-organ failure. This communication reviews the management of sildenafil failures in light of recent advances.

RECENT FINDINGS

Sildenafil failures can be attributed to either lack of efficacy or side effects; issues may involve the physician, patient, and his partner. Physicians may contribute to sildenafil failure and discontinuation because of inadequate instructions, lack of adequate follow-up, suboptimal dosing, lack of adequate trial, and insufficient clarification about safety issues. Studies have demonstrated that progression of endothelial dysfunction and diminished cavernosal smooth-muscle content are recognized organic factors which cause end-organ dysfunction and ultimately treatment failure.

SUMMARY

Proper counseling, medication optimization, and modifying associated risk factors can provide success in men who had initially failed sildenafil therapy for erectile dysfunction. Other treatment modalities that may be considered when sildenafil failure occurs include vacuum devices, intraurethral, and intracavernosal administration of vasoactive drugs alone or combined with sildenafil. Penile prosthesis implantation is considered as a last resort, if all first-line and second-line therapies fail.

Effect of Doxazosin With and Without Rho-Kinase Inhibitor on Human Corpus Cavernosum Smooth Muscle in the Presence of Bladder Outlet Obstruction

PURPOSE

We investigated the relationship of adrenergic responses in corpus cavernosum tissues in the presence of BOO using the alpha1-adrenergic receptor antagonist doxazosin (Pfizer, New York, New York) and the rho-kinase inhibitor Y-27632 (Calbiochem, San Diego, California).

MATERIALS AND METHODS

CCSM tissue was obtained from patients who underwent penile prosthesis implantation. Patients were divided into 2 groups according to the presence of BOO. The submaximal (EC80) concentration of phenylephrine (Sigma Chemical Co., St. Louis, Missouri) was calculated by evaluating adrenergic activity responses with cumulatively applied phenylephrine. After achieving a stable contraction plateau test compounds were put in an organ bath. The relaxant potencies of doxazosin and Y-27632 were expressed as the percent of inhibition of the contraction plateau induced EC80 concentration of phenylephrine. Relaxation responses in the 2 groups were compared.

RESULTS

At the highest dose of increasing concentrations phenylephrine generated 70% more contraction response in the BOO positive group than in the BOO negative group. Doxazosin and Y-27632 caused concentration dependent relaxation in CCSM precontracted by phenylephrine. With doxazosin significantly higher relaxation responses were attained in the BOO positive group in terms of log IC50 and the maximal relaxation response (p = 0.0353 and 0.0003, respectively). Maximum relaxation responses following Y-27632 administration were significantly higher in the BOO positive group.

CONCLUSIONS

The contractility of human corpus cavernosum is increased in the presence of BOO. Doxazosin and Y-27632 generate effective CCSM relaxation in the presence of BOO. Doxazosin and Y-27632 may be the alternatives for the treatment of erectile dysfunction associated with BPH.

Beneficial effects of extended-release doxazosin and doxazosin standard on sexual health

The prevalence of benign prostatic hypertrophy (BPH) and erectile dysfunction (ED) both increase with age, and increasing evidence suggests a common cause rather than independent age-related changes. Arterial hypertension often accompanies these urological disorders, suggesting the possibility that increased alpha-adrenoceptor activity may be causal in all three conditions. As evidence for this model, alpha-adrenoceptor antagonists such as doxazosin produce therapeutically beneficial effects in lowering blood pressure, reducing prostate growth and BPH symptoms, and relieving ED. At postjunctional alpha(1)-receptors in the corpus cavernosa, noradrenaline causes vascular smooth muscle cell contraction, restricting blood flow, resulting in penile detumescence. Just as alpha-adrenoceptor antagonism results in systemic vasorelaxation to lower blood pressure, the same mechanism in the penis modulates the effects of noradrenaline to favour vasodilatation, resulting in improved erectile function. Increasing clinical evidence attests to the effectiveness of doxazosin in relieving ED, even in patients refractory to ED-specific treatment, as well as in reducing BPH symptoms and elevated blood pressure.

Alpha-adrenoceptors are a common denominator in the pathophysiology of erectile function and BPH/LUTS - implications for clinical practice

A literature search of PubMed documented publications and abstracts from proceedings of scientific meetings was made to review the available data on benign prostatic hyperplasia/lower urinary tract symptoms (BPH/LUTS) and erectile dysfunction (ED) with a special focus on the role of alpha-adrenoceptors as critical mediators of pathophysiology. The reader is introduced to clinical results on the therapeutic potential of alpha-blockers alone and in combination with phosphodiesterase type 5 (PDE-5) inhibitors in the treatment of ED associated with LUTS/BPH. Epidemiological studies clearly show that an association exists between ED and LUTS/BPH. The severity of LUTS is correlated with the risk for ED. A significant number of LUTS/BPH patients are nonresponsive to the common ED treatment with PDE-5 inhibitors. As smooth muscle contractility is regulated by adrenoceptors in the corpus cavernosum, prostate and detrusor, the alpha-adrenoceptor system may be considered a common pathophysiological mediator in the development of ED and LUTS/BPH. Blockade of alpha-adrenoceptors for the treatment of BPH/LUTS may have the potential of improving sexual function. Conversely, PDE-5 inhibitors may exhibit positive effects in LUTS patients. Pilot studies on combination regimens of alpha-adrenoceptor antagonists and PDE-5 inhibitors have yielded encouraging results in LUTS patients with persistent ED. On the basis of pharmacological and clinical evidence, it is established that the alpha-adrenoceptor system plays an important role in the pathophysiology of ED and LUTS secondary to BPH. Larger trials on the combination of alpha-adrenoceptor antagonists with PDE-5 inhibitors are necessary to develop an integrated treatment approach for BPH/LUTS patients with comorbid ED.

Effects of ??1-Adrenoceptor Antagonists on Male Sexual Function

alpha(1)-Adrenoceptor antagonists such as alfuzosin, doxazosin, tamsulosin and terazosin are first-line agents for the treatment of lower urinary tract symptoms suggestive of benign prostatic hyperplasia (BPH), but are only second-line agents (doxazosin and terazosin only) for the treatment of arterial hypertension. Sexual function is complex and includes multiple domains such as sexual desire (libido), erectile function and ejaculatory function. Erectile and ejaculatory functions are frequently reduced in patients with BPH and can impact on their quality of life. Therefore, the treatment of BPH should aim to maintain or even restore sexual function.alpha(1)-Adrenoceptor antagonists lack major effects on sexual desire in placebo-controlled studies. Reports on erectile function are inconsistent, with both beneficial and adverse effects being reported, but impotence can occur in some patients without clear differences between drugs. Ejaculatory dysfunction during treatment may represent (relative) an ejaculation. It occurs more frequently with tamsulosin than with other drugs of this class, but the differences are not big enough to be consistently detectable in directly comparative studies. We propose that such differences between drugs should be weighed against differences in cardiovascular tolerability when choosing the optimal treatment for each patient.

Comparison of clinical trials with sildenafil, vardenafil and tadalafil in erectile dysfunction

Erectile dysfunction (ED) affects up to 50% of men, between 40 and 70 years of age. In the first major trial of sildenafil in ED, at 24 weeks, improved erections were reported by 77 and 84% of men taking sildenafil 50 and 100mg, respectively. Subsequently, sildenafil has been reported to be effective in men with ED associated with diabetes and prostate cancer, and in psychogenic ED. Sildenafil is safe in men with coronary artery disease, provided it is not used with the nitrates (a contraindication). The most commonly reported adverse effects with sildenafil are headache, flushing and dyspepsia. Vardenafil is more potent and more selective than sildenafil at inhibiting phosphodiesterase-5. Vardenafil is similarly effective to sildenafil in the treatment of ED. The only advantage that vardenafil has over sildenafil is that it does not inhibit phosphodiesterase-6 to alter colour perception, a rare side effect which sometimes occurs with sildenafil. Tadalafil has a longer duration of action than sildenafil and vardenafil. Tadalafil is similarly effective as sildenafil in the treatment of ED. In comparison studies, tadalafil is preferred to sildenafil (50/100mg) by men with ED, possibly because of its longer duration of action. Of the phosphodiesterase inhibitors, tadalafil may displace sildenafil as the drug of choice among men with ED.

Safety and Tolerability of Oral Erectile Dysfunction Treatments in the Elderly

Erectile dysfunction (ED) is a common medical condition that affects the sexual life of millions of men worldwide. It is generally accepted that sexual function tends to decline with aging, which is often associated with a higher prevalence of sexual problems, including ED and loss of libido. As the mean age of men seeking medical help for sexual dysfunction continues to increase, it is important to assess the safety and tolerability of currently available medical treatments in elderly men, who often share other co-morbidities that should be carefully evaluated when any type of ED therapy is considered. With this aim in mind, a MEDLINE search was conducted from 1 January 1998 to 31 May 2004 to identify studies assessing the efficacy, safety and tolerability of treatments for ED in the elderly. Particular care was taken to assess the cardiovascular safety of oral drugs for ED in this subset of patients, who often have multiple cardiovascular risk factors which contribute to a complicated clinical scenario. The most important conclusion of the paper is that the high efficacy, reliability, safety and tolerability of oral ED treatments makes them appropriate first-line therapies for elderly patients with ED.

Efficacy of extended-release doxazosin and doxazosin standard in patients with concomitant benign prostatic hyperplasia and sexual dysfunction

OBJECTIVE

To report a comprehensive retrospective analysis of the favourable effects of doxazosin extended-release (XL) and doxazosin standard on the sexual health of patients with comorbid benign prostatic hyperplasia (BPH) and erectile dysfunction (ED), augmenting a previous study of 680 patients with symptomatic BPH.

PATIENTS AND METHODS

Men with BPH and aged 50-80 years participated in a randomized, double- blind, double-dummy, parallel-group, multicentre trial, completing a 2-week, single-blind, placebo run-in period before receiving doxazosin XL 4 or 8 mg once daily or doxazosin standard 1-8 mg once daily for 13 weeks. Baseline sexual function and changes from baseline after treatment with doxazosin were evaluated from responses of the International Index of Erectile Function (IIEF) questionnaire (with dysfunction defined as a score of < or = 3 for any question) and the five domains for erectile function (intercourse satisfaction, orgasmic function, sexual desire and overall sexual satisfaction).

RESULTS

Of 680 patients randomized into the trial, 237 (35%) had ED at baseline; in these patients there were statistically and clinically significant improvements in each of the five IIEF domains with XL and standard doxazosin (P < or = 0.0019), with the range of improvement being from 13% to 41%. There were no significant differences between treatment groups. Doxazosin XL consistently improved sexual function, as assessed by the individual questions of the IIEF questionnaire. There was no statistically significant difference between groups for any sexual function question analysed.

CONCLUSION

Doxazosin XL and standard improved sexual function in men with concomitant BPH and ED at baseline. This may represent an action independent of relieving lower urinary tract symptoms, because the beneficial effect of doxazosin was reported in patients with no symptomatic BPH.

[Combination therapy in benign prostatic hyperplasia (BPH)]

Because of the constant progress in our understanding of the physiopathology of benign prostatic hyperplasia, it is now possible to propose a more rational use of combination therapy, which is often used empirically, though not recommended, in routine practice. This chronic disorder, which is in fact more complex than it appears, may benefit in theory from a combination of molecules with different complementary action mechanisms. Prostatic obstruction may be treated either by alphablockers with their peripheral muscle-relaxant action on the smooth muscle fibers of the prostate and bladder neck, or by 5-alpha-reductase inhibitors for their reducing effect on gland volume. Irritative bladder symptoms involving the detrusor may be treated by antimuscarinics and to a lesser extent by alphablockers. Currently available data from recent studies suggest that a combination of an alphablocker and a 5-alpha-reductase inhibitor may be useful in patients with symptomatic BPH and a prostate of more than 40 grams with PSA > 1.6 ng/ml. Combinations including an antimuscarinic are effective in patients with BPH with marked irritative symptoms. Finally, the combination of an alphablocker and a phosphodiesterase type 5 inhibitor may be useful in patients with lower urinary tract symptoms (LUTS) associated with erectile dysfunction.

Future options for combination therapy in the management of erectile dysfunction in older men

The prevalence of erectile dysfunction (ED) has dramatically increased in parallel with the aging of the Western industrialised population. The estimated prevalence of ED worldwide in 1995 was 152 million men. As the population in industrial nations ages, an estimated 322 million men will be affected by ED by the year 2025. Oral drug therapy with the phosphodiesterase (PDE) type 5 inhibitor sildenafil fails in some patients with ED; however, several different classes of drugs demonstrate efficacy in treating ED, creating the potential for pharmacological combination therapy. Pharmaceutical products that lead to the activation of or an increase in cyclic nucleotides (cyclic adenosine monophosphate and cyclic guanosine monophosphate), with or without nitric oxide donors or nitrates, as well as alpha-adrenoceptor antagonists, have been used to treat ED. Sildenafil has been used in combination with alprostadil (prostaglandin E1) and administered via intraurethral or intracavernous route. Successful intercourse using this combination of agents varies from 47% to 100% following failed monotherapy. Various combination therapies for ED are being studied using PDE5 inhibitors, together with other agents, alpha-adrenoceptor antagonists, and testosterone replacement therapy for men with hypogonadism. The combination of centrally acting agents with PDE5 inhibitors, e.g. a regimen of apomorphine plus PDE5 inhibitor, is an attractive approach because the two therapies target different mechanisms. New PDE5 inhibitors such as vardenafil should be tried first as therapy for sildenafil nonresponders before exploring any combination therapy options. Preliminary observations of combination therapy have been encouraging and provide a scientific rationale for prospective, randomised clinical trials with adequate numbers of patients.

Viability and safety of combination drug therapies for erectile dysfunction

PURPOSE

In some patients with erectile dysfunction (ED) oral, topical or intracavernous drug therapy fails. However, several classes of drugs demonstrate efficacy for ED, creating the potential for pharmacological combinations preferable to implantation of a penile prosthesis.

MATERIALS AND METHODS

Preliminary reports suggest that combining oral, topical or intracavernous drugs may salvage patients in whom monotherapy fails.

RESULTS

Agents that lead to activation or increases in cyclic nucleotides (cyclic adenosine monophosphate and guanosine monophosphate) with or without nitric oxide donors or nitrates, or alpha-adrenergic antagonists have been used to treat ED. The phosphodiesterase-5 inhibitor sildenafil has been combined with alprostadil (prostaglandin E1) and administered by either the intraurethral or intracavernous route. Successful intercourse following this combination varies from 47% to 100% when monotherapy with each has failed. The introduction of apomorphine has led to its unapproved use in combination with sildenafil in Europe. Combination strategies may allow lower drug doses and reduced adverse effects.

CONCLUSIONS

The encouraging preliminary observations combined with the potential for adverse events provide a scientific rationale for prospective, randomized clinical trials with adequate numbers of subjects.

Oral agents for erectile dysfunction

Erectile dysfunction is a common disease affecting the lives of millions of men worldwide. Sildenafil was the first oral treatment licensed for male erectile dysfunction. However, there are now a number of other options available. In this article the currently available oral treatments are reviewed.

Sildenafil in erectile dysfunction: a critical review

Sildenafil citrate (Viagra) is a potent orally active cGMP-specific phosphodiesterase type 5 (PDE5) inhibitor that is effective as a peripheral conditioner in the treatment of male erectile dysfunction (ED) of organic, psychogenic or mixed aetiology. Sildenafil is the first effective oral agent in the management of ED that has had a revolutionary impact on management of ED. The present review has been subdivided into five major sections. Based on the most recent peer-reviewed publications, the first section is aimed at critically evaluating PDE5 selectivity as well as the pharmacokinetics and pharmacodynamics of the drug, mainly to assess the best doses for each group of patients (i.e. adult and elderly men). Effectiveness in a broad spectrum ED population is the subject of the second section of the review, principally reporting post-marketing company-independent results. Safety and tolerability are the key concerns of the third section, with a broad consideration of the most commonly reported adverse events. Special attention has been paid to the cardiovascular safety of the drug, chiefly outlining the positive and potentially protective cardiac effects of sildenafil. Moreover, the impact of sildenafil in special patient populations is considered, namely in men complaining of diabetes mellitus, depression, neurological disorders, renal failure and those who have undergone a radical prostatectomy. Sildenafil and the ageing male has been especially underlined. Finally, the review covers a few new potential applications of sildenafil in ED patients with regard to high-dose treatment and combination therapy. The review ends with several considerations regarding the direct and/or indirect impact of sildenafil over quality of life and quality of partnership.

Current oral treatments for erectile dysfunction

Erectile dysfunction (ED) is defined as the inability to achieve and maintain a penile erection adequate for satisfactory sexual intercourse. It is a significant male health problem of global dimensions affecting approximately 150 million men worldwide. A broad range of options are currently available for the management of ED. They include oral agents (phosphodiesterase 5 inhibitors, dopamine agonists and alpha-receptor blocking drugs), intracavernosal injection (papaverine, phentolamine, prostaglandin E1, vasoactive intestinal peptide), transurethral vasoactive agents (prostaglandin E1), vacuum erection devices, vascular surgery and penile prostheses. Here we review the physiology of penile erection and the currently available oral preparations. In addition, novel therapeutic strategies to improve erectile function are discussed.