PDE5-Is for the Treatment of Concomitant ED and LUTS/BPH

Overview of current pharmacotherapeutic options in benign prostatic hyperplasia

INTRODUCTION

Benign prostatic hyperplasia (BPH) represents the histological entity of prostate cell proliferation, which inflicts a gradually increasing obstruction of the bladder outlet and is accompanied by a progressing manifestation of lower urinary tract symptoms (LUTS). BPH management algorithm includes conservative measures, pharmaceutical agents, and surgical procedures.

AREAS COVERED

A comprehensive literature review was performed using PubMed, Scopus, and Google Scholar databases to identify publications written in English, analyzing BPH pharmaceutical treatment. The search was conducted from January 2000 to January 2023. Six main drug classes can be administered, either as monotherapy or in combination. Furthermore, the authors provide current direction of research on future medications, which focuses on a more etiological interference to the BPH pathophysiological mechanism.

EXPERT OPINION

The available medications represent an effective first-line step of BPH/LUTS therapy. Currently, the administration of BPH medications is tailored to patient/disease characteristics and entails long-time adherence to therapy. The emergence of new surgical modalities, which combine significantly lower morbidity compared to standard procedures and more durable effects than the available medications, seems to challenge the current treatment algorithm. More direct comparisons and the increasing experience with these surgical modalities will delineate the switch points between various therapy levels along the BPH management sequence.

A Review on the Pharmacological Importance of PDE5 and Its Inhibition to Manage Biomedical Conditions

Phosphodiesterase type 5 (PDE5) is a cyclic GMP (cGMP) specific protein. It hydrolyzes the phosphodiesterase linkage and catalyzes the conversion of cGMP to 5’ GMP, which controls different physiological activities of the body. PDE5 is associated with biomedical conditions like neurological disorders, pulmonary arterial hypertension, cardiomyopathy, cancer, erectile dysfunction, and lower urinary tract syndrome. Inhibition of PDE5 has now been proven pharmaceutically effective in a variety of therapeutic conditions. Avanafil, tadalafil, sildenafil, and vardenafil are the most commonly used PDE5 inhibitors (PDE5i) today which are often used for the management of erectile dysfunction, lower urinary tract syndromes, malignancy, and pulmonary arterial hypertension. However, these synthetic PDE5i come with a slew of negative effects. Some of the most common side effects include mild headaches, flushing, dyspepsia, altered color vision, back discomfort, priapism, melanoma, hypotension and dizziness, non-arteritic anterior ischemic optic neuropathy (NAION), and hearing loss. In light of the potential negative effects of this class of medications, there is a lot of room for new, selective PDE5 inhibitors to be discovered. We have found 25 plant botanical compounds effectively inhibiting PDE5 which might be useful in treating a variety of disorders with minimal or no adverse effects.

Phosphodiesterase as a Target for Cognition Enhancement in Schizophrenia

Schizophrenia is a severe mental disorder that affects more than 1% of the population worldwide. Dopamine system dysfunction and alterations in glutamatergic neurotransmission are strongly implicated in the aetiology of schizophrenia. To date, antipsychotic drugs are the only available treatment for the symptoms of schizophrenia. These medications, which act as D2-receptor antagonist, adequately address the positive symptoms of the disease, but they fail to improve the negative symptoms and cognitive impairment. In schizophrenia, cognitive impairment is a core feature of the disorder. Therefore, the treatment of cognitive impairment and the other symptoms related to schizophrenia remains a significant unmet medical need. Currently, phosphodiesterases (PDEs) are considered the best drug target for the treatment of schizophrenia since many PDE subfamilies are abundant in the brain regions that are relevant to cognition. Thus, this review aims to illustrate the mechanism of PDEs in treating the symptoms of schizophrenia and summarises the encouraging results of PDE inhibitors as anti-schizophrenic drugs in preclinical and clinical studies.

Scar-modulating agents post urethroplasty: Could phosphodiesterase-5 inhibitors be the answer?

Background:

Phosphodiesterase enzyme inhibitors (PDEIs) are most commonly prescribed by urologists for the treatment of erectile dysfunction. They are also gaining popularity as a treatment for lower urinary tract symptoms, based on their effect on smooth muscles – either vascular smooth muscles or smooth muscles in the urinary tract. For vascular smooth muscles, they cause vasodilation, enhanced microcirculatory haemodynamics through inhibition of platelet aggregation and adhesion, induction of apoptosis of adhesion fibroblasts and a reduction in the scarring process.

Methodology:

We reviewed articles published in English and indexed in the PubMed, Embase and Google Scholar databases, and consulted textbooks. Key search terms used were: urethral stricture, anti-fibrotic, scar-modulating agent, PDEIs, urethral scarring and urethroplasty. We created a synopsis of relevant articles, including original research studies and reviews. Level of evidence: Not applicable.

Management of benign prostate hyperplasia (BPH) by combinatorial approach using alpha-1-adrenergic antagonists and 5-alpha-reductase inhibitors

Currently, the main available treatments for benign prostate hyperplasia (BPH) are alpha-1 adrenergic receptor antagonists (ARAs), 5-alpha reductase inhibitors (5-αRI), anticholinergics, and Phosphodiesterase-5 inhibitors. Recent studies support the combined therapy approach using ARAs with 5-αRI for lower urinary tract symptoms (LUTS) in BPH patients at risk of clinical progression. We aimed to review BPH management in select group of randomized controlled trials by combination therapy with ARAs and 5-αRIs compared to monotherapy with either drug with respect to the safety and efficacy. A total of 6 randomized controlled trials (RCTs) involving comparison of combination therapy with monotherapy using ARAs and 5-αRIs were retrieved from PubMed Central and reviewed for international prostate symptom score (IPSS), quality of life (QoL), post-residual urinary flow rate (PUF), and clinical progression. The results significantly favour the treatment group that received the combination therapy in comparison with the groups receiving monotherapy. However, outcome with regard to prostate volume showed insignificant improvement when the combination therapy is compared with 5- αRIs alone, rather than ARAs. In conclusion, combination therapy using ARAs and 5-αRI is better than monotherapy in the patients of BPH. Fixed dose combination (FDC), a type of combination, is also cost-effective and its side-effects profile resembles to that of monotherapy.

Patient characteristics and treatment patterns for patients with benign prostatic hyperplasia, erectile dysfunction or co-occurring benign prostatic hyperplasia and erectile dysfunction in general practices in the UK: a retrospective observational study

AIMS

The aim of this study was to assess patient characteristics, medication treatment patterns and healthcare resource utilization among men with existing erectile dysfunction (ED) or benign prostatic hyperplasia (BPH), who are newly diagnosed with the second condition (BPH or ED) compared with those with only one condition.

METHODS

This retrospective cohort study utilized the Clinical Practice Research Datalink. Males, aged 40 years or older, newly diagnosed with ED or symptomatic BPH between 1 June 2010 and 31 May 2011, were selected. Patient demographics, existing comorbidities and baseline medication use were analysed. Treatments initiated for the incident condition and treatment patterns were reported at 6, 12, 18 and 24-months postdiagnosis. Referrals to urologists and visits to general practitioners were reported around diagnosis and during follow-up.

RESULTS

This study included 11,501 incident patients with BPH, of which 23% had a prior ED diagnosis and 9,734 incident patients with ED, of which 17% had a prior BPH diagnosis. The average age at diagnosis of BPH was similar across both cohorts. Among incident patients with ED, those with prior diagnosis of BPH were diagnosed at an older average age (65 ± 9.2 years) compared to those without BPH (57 ± 9.1 years). The majority of patients in both incident BPH cohorts (62.9-65.5%) were prescribed alpha-blockers as initial treatment. The majority of patients in both incident ED cohorts (49.6-51.6%) were prescribed sildenafil as initial treatment followed by tadalafil (24.3-26.0%). At 12 months, 50% of incident patients with BPH and 80% of patients with ED had discontinued the therapy initiated.

CONCLUSION

This study found that in the UK, patients with co-occurring BPH and ED when newly diagnosed with the second condition initiated the same treatments as those without prior ED or BPH. During the first year, treatment patterns including discontinuation were comparable in the groups with one of the conditions and co-occurring BPH and ED.

Cross-sectional and longitudinal associations of sexual function with lower urinary tract symptoms in men with benign prostatic hyperplasia

PURPOSE

We examine the cross-sectional associations between baseline characteristics and sexual function and the longitudinal associations between change in lower urinary tract symptoms and change in sexual function among men with benign prostatic hyperplasia.

MATERIALS AND METHODS

We studied lower urinary tract symptoms assessed by the AUA-SI and sexual function determined by the BMSFI in men enrolled in the MTOPS study. The cross-sectional cohort included 2,916 men who completed the BMSFI at baseline. The longitudinal cohort included 672 men who were randomized to placebo and had completed the BMSFI at baseline and at least once during a 4-year followup. Multiple adjusted linear modeling for each domain of the BMSFI was performed to assess associations of sexual function with lower urinary tract symptoms.

RESULTS

After adjustment for baseline demographic and clinical characteristics, increased age, less education, obesity and severe lower urinary tract symptoms were each significantly associated with poorer sexual drive, erectile function, ejaculatory function, sexual problem assessment and overall satisfaction in the cross-sectional cohort. However, none of these baseline characteristics predicted change in sexual function in the longitudinal cohort. Decline in sexual function in all sexual function domains associated with worsening of lower urinary tract symptoms in this group was small.

CONCLUSIONS

Increased age, less education, obesity and more severe lower urinary tract symptoms were individually associated cross-sectionally, but not longitudinally, with poorer sexual function in men with lower urinary tract symptoms/benign prostatic hyperplasia. The decline in sexual function associated with worsening of lower urinary tract symptoms in men assigned to placebo was small.

Effect of chronic Sildenafil treatment on the prostate of C57Bl/6 mice

Sildenafil is a potent and selective inhibitor of phosphodiesterase-5 (PDE5) and is considered first-line therapy for erectile dysfunction. Nowadays, Sildenafil is used extensively throughout the world on patients with pulmonary hypertension. However, few studies have evaluated the possible side effects of chronic Sildenafil treatment on the male reproductive system, specifically in the prostate. In the present study, it was demonstrated via morphological and ultrastructural analysis that chronic treatment with Sildenafil induced an enhancement of the glandular activity of the prostate. In addition, mice treated with Sildenafil showed a significant increase in testosterone serum levels. However, no statistically significant differences were observed in nitric oxide serum levels, or in sGC, eNOS, PSA and TGF-β prostatic expression. In conclusion, the present study suggests that chronic use of Sildenafil does not cause evident prostatic damage, and therefore, can be used pharmacologically to treat a variety of disorders.

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.

Effectiveness of tadalafil 5 mg once daily in the treatment of men with lower urinary tract symptoms suggestive to benign prostatic hyperplasia with or without erectile dysfunction: results from naturalistic observational TadaLutsEd study

INTRODUCTION

Naturalistic clinical trials provide data on the effectiveness of drugs in nonexperimental and everyday situations and are extremely helpful for decision-making purposes and for confirming experimental findings in clinical trials. No data have been published from naturalistic studies performed in patients with lower urinary tract symptoms suggestive of benign prostatic hyperplasia (LUTS/BPH) with or without erectile dysfunction (ED) and treated with phosphodiesterase type 5 inhibitors.

AIM

The aim of this study (TadaLutsEd Study) was to assess, in the context of medical practice, the effectiveness of tadalafil 5 mg once daily in patients with LUTS/BPH with or without erectile dysfunction.

METHODS

The study was a 6-week uncontrolled, prospective, open-label, multicentric, observational study. The patient population involved sexually active males aged ≥ 50 years, diagnosed with LUTS/BPH with or without concomitant ED, and treated with tadalafil 5 mg daily in accordance with standard urological practice.

MAIN OUTCOME MEASURES

Effectiveness was assessed through the self-administered International Prostate Symptom Score (IPSS) questionnaire; quality of life was evaluated through the IPSS quality of life section (IPSS-QoL). The patients were also evaluated with the International Index of Erectile Function (IIEF-5). Adverse events were recorded. Statistical analyses using paired data samples was applied (Wilcoxon signed-ranks test).

RESULTS

Sixty-two patients (mean age 62.2 years) completed the treatment, of whom 85.5% showed improvement in their urinary symptoms. Pre- and post-treatment differences in the IPSS, IPSS-QoL, and IIEF-5 scores were statistically significant at 4.4, 1, and 5.4 points, respectively (P < 0.0001). Tadalafil was well tolerated, and adverse events were mild, with a discontinuation rate of 1.6%.

CONCLUSION

According to study results, the use of tadalafil 5 mg once daily in a nonselected patient population with LUTS/BPH with or without ED led to improvements in terms of symptoms and quality of life and exhibited a safety profile similar to that obtained in controlled tadalafil clinical trials.