A review on pharmacological options for the treatment of erectile dysfunction: state of the art and new strategies

INTRODUCTION

Erectile dysfunction (ED) affects between 12.9% and 28.1% of men worldwide, presenting a strong aged-correlated prevalence. Several pharmacological treatments are currently available for ED, which can be classified into oral, injection, and topical/intraurethral therapies.

AREAS COVERED

Extensive research on PubMed/MEDLINE until February 2023 was performed. For each of the aforementioned drug classes, available molecules, and formulations, their efficacy and most common adverse events as well as general guidelines on prescription were investigated and extensively described. A glimpse into future directions regarding ED pharmacotherapy is also present.

EXPERT OPINION

In recent years, there have been significant developments in pharmacological treatments for ED. It is essential for physicians to identify the best treatment option for patients based on their preferences and sexual habits. The treatment approach for ED has shifted from a sequential to a parallel paradigm, where all treatment options are available as first-line therapies. While there are promising regenerative therapies for ED, such as shockwaves and platelet-rich plasma injections, pharmacological treatment is still the most effective option for most patients.

Short- and long-term follow-up results of daily 5-mg tadalafil as a treatment for erectile dysfunction and premature ejaculation

Objective

To evaluate the safety and effectiveness of daily 5-mg tadalafil treatment for men who have erectile dysfunction (ED) and premature ejaculation (PE), and to assess the long-term follow-up for ED and PE improvement persistence years after the cessation of medication.

Patients and Methods

A prospective, single-blind, randomised study included 160 patients with ED and PE. All were evaluated using the International Index of Erectile Function (IIEF-5) questionnaire to evaluate ED and intravaginal ejaculatory latency time (IELT) for PE. Patients were subdivided into two equal groups. Group I (80 patients) treated with daily 5-mg tadalafil for 3 months, and Group II (80 patients) treated with a placebo for the same period. After 3 months of treatment and 2 years later after cessation of tadalafil, all patients were assessed for ED and PE.

Results

The mean (SD) IELT and IIEF-5 score pre-treatment were 37 (11.24) s and 13.2 (4.2) for Group I, while in Group II they were 35.98 (10.8) s and 13.12 (4.11), respectively. After 3 months of treatment, the mean (SD) IELT in Group I showed a highly significant improvement from 37 (11.24) s to 120.5 (47.37) s (P < 0.001) but Group II showed no significant improvement from baseline to [39.43 (13.6) s; P > 0.05]. For the IIEF-5 score, there was a highly significant improvement from baseline to 20.45 (4.5) in Group I (P < 0.001), while there was no significant difference in Group II from baseline to [15 (4.84); P > 0.05]. At 2 years after cessation of tadalafil, there was statistically significant improvement in the IELT and IIEF-5 from baseline to endpoint .

Conclusion

Oral daily 5-mg tadalafil was effective, tolerable, and safe treatment for patients with ED and PE. Long-term follow-up at 2 years confirmed the persistence of a significant improvement for both ED and PE.

Abbreviations: ED: erectile dysfunction; IIEF-5: five-item version of the International Index of Erectile Function questionnaire; IELT: intravaginal ejaculatory latency time; OAD: once-daily; PDE5i: phosphodiesterase-5 inhibitors; PE: premature ejaculation; PRN: pro re nata

Evaluation of the long-term safety and effectiveness of tadalafil once daily in Chinese men with erectile dysfunction: interim results of a multicenter, randomized, open-label trial

Once-daily tadalafil administration has been well established; however, studies about tadalafil once-daily treatment in the Chinese population are lacking. In this phase 4, postmarketing study, we ascertained the long-term safety and effectiveness of tadalafil 2.5 mg and 5.0 mg once daily in Chinese men with erectile dysfunction (n = 635). The primary endpoint of the study was safety at 12 months as assessed by the proportion of patients experiencing at least one treatment-emergent adverse event (serious or nonserious). The secondary endpoints included safety and effectiveness, measured by the International Index of Erectile Function-Erectile Function (IIEF-EF) domain scores. Similar adverse events to the known safety profile of tadalafil, such as nasopharyngitis, upper respiratory tract infection, headache, and dizziness, were detected. No new cardiovascular safety concerns were observed. After 3 months of treatment, significant increases in IIEF-EF domain scores were detected for both 2.5-mg (least squares [LS] mean change: 6.3; 95% confidence interval [CI]: 5.4–7.1; P < 0.001) and 5.0-mg (LS mean change: 7.4; 95% CI: 6.8–7.9; P < 0.001) tadalafil doses, and significance was maintained up to 12 months. In addition, approximately 40% of patients regained normal erectile function (IIEF-EF ≥26) following 1 year of tadalafil once-daily treatment. The findings in this study provide evidence for the extended effectiveness and tolerability of tadalafil, demonstrating no new safety concerns, in a Chinese population and make once-daily tadalafil administration a viable option for improving sexual performance and satisfaction in Chinese men with erectile dysfunction.

Erectile Dysfunction: A Primer for in Office Management

Introduction: Optimizing erectile dysfunction (ED) remains a clinically significant endeavor as insufficient outcomes from oral, injectable and even surgical approaches to treatment remain less than ideal. In this report, we integrate evolving knowledge and provide an algorithmic approach for the clinician to fine-tune management. Methods: We performed a PubMed and Medline search of Erectile Dysfunction treatment optimization, enhanced patient efficacy for ED, and why men fail ED treatment. All relevant papers for the past two decades were reviewed. Results: Establishing the goals and objectives of the patient and partner while providing detailed instructions for treatment can minimize failures and create an environment that allows treatment optimization. A thorough work-up may identify reversible or contributing causes. We identified several areas where treatment of ED could be optimized. These include; management of associated medical conditions, lifestyle improvements, PDE5 inhibitor prescription strategies, management of hypogonadism and the initiation of intracavernosal injection therapy (ICI). Conclusions: In our view, once a man presents for help to the clinician, use of the simple strategies identified in this review to optimize the tolerability, safety and effectiveness of the selected treatment should result in enhanced patient and partner satisfaction, with improved outcomes.

Low dose daily versus on-demand high dose tadalafil in diabetic patients with erectile and ejaculatory dysfunction

The aim was to compare the differences between daily 5 mg and on-demand 20 mg tadalafil use in diabetic patients with erectile dysfunction (ED), and the effects of two different tadalafil protocols on ejaculatory and lower urinary tract symptoms (LUTS). Of the 63 diabetic patients with ED, 31 were given 5 mg tadalafil once a day, and 32 were given 20 mg tadalafil on-demand four times a month over three months. Erectile function, erectile hardness, ejaculatory function, and LUTS were assessed at pretreatment, first- and third-month controls. Both tadalafil protocols increased International Index of Erectile Function (IIEF) scores in all patients under 65 years, whereas patients older than 65 years did not benefit. Ejaculatory function, the quality of the hardness of an erection, and LUTS improved in both groups in the study. Tadalafil improved sexual function with acceptable side effects in diabetic men with ED. Both protocols equally improved LUTS and the quality of the erection. Daily use of 5 mg of tadalafil significantly improved the quality of ejaculation and LUTS more than the on-demand use of 20 mg of tadalafil. It may be beneficial to give 5 mg tadalafil daily to patients over 65 years old who do not benefit from treatment with 20 mg of tadalafil or in patients who have LUTS over 65 years old.

Udenafil, a Phosphodiesterase 5 Inhibitor, Reduces Body Weight in High-Fat-Fed Mice

Purpose

High-fat (HF) feeding induces hypothalamic leptin resistance via the activation of toll-like receptor 4 (TLR4). TLR4 deficiency confers resistance to diet-induced obesity. Udenafil, an anti-impotence drug, inhibits TLR4 in airway epithelial cells in vitro. In this study, we evaluated whether udenafil suppressed the hypothalamic expression of TLR4 and reduced body weight.

Materials and Methods

The hypothalamic expression of TLR4, phosphodiesterase 5 (PDE5), nuclear factor-κB (NF-κB), and myeloid differentiation primary response gene 88 (Myd88) was analyzed by real-time polymerase chain reaction after treating mice for 2 days with udenafil (0, 12, 120, or 600 µg/d). Furthermore, the hypothalamic expression of TLR4, pro-opiomelanocortin (POMC), and neuropeptide Y (NPY) was analyzed after 9 days' treatment with udenafil and/or leptin. We also measured body weight and food intake following 9 days of udenafil and/or leptin treatment in control- and HF-fed mice.

Results

Udenafil suppressed hypothalamic TLR4 mRNA expression dose-dependently. The changes were associated with decreased PDE5, NF-κB, and Myd88 expression. Udenafil treatment for 9 days reduced body weight and caloric intake in HF-fed mice. This may have been associated with the suppression of NPY expression that was elevated by HF feeding. POMC expression was not affected by udenafil. However, udenafil did not augment the effects of leptin on the reduction of body weight and caloric intake in HF-fed mice.

Conclusions

These results suggested that udenafil reduced body weight by suppressing hypothalamic TLR4 mRNA expression in HF-fed mice and the combination effect of udenafil and leptin was additive rather than synergistic.

Efficacy of Continuous Dosing of Tadalafil Once Daily vs Tadalafil On Demand in Clinical Subgroups of Men With Erectile Dysfunction: A Descriptive Comparison Using the Integrated Tadalafil Databases

Introduction

Various factors play a role in the development of erectile dysfunction (ED).

Aim

To provide a descriptive comparison of erectile function response for tadalafil on-demand (PRN) and once-daily (OAD) dosing regimens in patients with common comorbid conditions, treatments, or risk factors that can be considered when treating ED.

Methods

In total, 17 PRN and 4 OAD placebo-controlled studies were included in the integrated database in these pooled analyses. Data were analyzed from patients treated with placebo, tadalafil 10 mg (low dose), and 20 mg (high dose) for the PRN studies and placebo, tadalafil 2.5 mg (low dose), and 5 mg (high dose) for the OAD studies.

Main Outcome Measures

The effects of tadalafil were measured using the International Index of Erectile Function administered from baseline to week 12. A descriptive comparison of the efficacy of tadalafil PRN vs OAD was examined in the clinical populations.

Results

Baseline characteristics of 4,354 men were comparable between the PRN and OAD groups, with differences seen only in the variables of race, body mass index (BMI) of at least 30 kg/m², and alcohol use. Tadalafil was efficacious at improving erectile function for all clinical populations, except for the low-dose OAD group, which demonstrated a weaker effect vs placebo than the high-dose OAD group, and the low- and high-dose PRN groups vs placebo for patients with BMI of at least 30 kg/m² for patients without a cardiovascular disorder, smokers, patients with ED duration shorter than 1 year, and patients without previous phosphodiesterase type 5 inhibitor use. Tadalafil was efficacious for patients with or without diabetes mellitus, arterial hypertension, hyperlipidemia, and alcohol use at baseline.

Conclusion

Tadalafil OAD and PRN regimens showed efficacy in patients with ED. No clinical populations of patients with ED seemed to benefit overwhelmingly from one dose regimen over the other.

A prospective longitudinal survey of erectile function status in symptomatic benign prostatic hyperplasia patients treated with dutasteride

We prospectively evaluated erectile function (EF) using the Sexual Health Inventory for Men (SHIM) and the erectile hardness score (EHS) as well as urinary statuses using the International Prostate Symptom Score (IPSS) and Overactive Bladder Symptom Score (OABSS) before and 3, 6, and 12 months after a daily treatment with 0.5 mg dutasteride (DUT). Significant improvements were observed in IPSS and OABSS in 98 patients with the DUT treatment, and the effects were similar between 28 patients with potency with baseline SHIM of 8 or greater and 70 severe erectile dysfunction (ED) patients at baseline. In the 28 patients with potency, significant decreases were observed in SHIM and EHS after 3, 6, and 12 months of the DUT treatment, with the severity of ED according to SHIM deteriorating in half of these patients after 12 months of the DUT treatment. Eighteen out of 28 patients (64.3%) with potency at baseline had awareness of the occurrence of ED before the DUT treatment, were younger, and had higher SHIM and EHS just before the DUT treatment than their counterparts. Regular assessments of EF may be needed, especially in younger patients and those with higher levels of EF before the administration of DUT.