Tadalafil for the treatment of benign prostatic hyperplasia

Introduction: In men, lower urinary tract symptoms (LUTS) are primarily attributed to benign prostatic hyperplasia (BPH). Therapeutic options are targeted to relax prostate smooth muscle and/or reduce prostate enlargement.

Areas covered: This article reviews the major preclinical and clinical data on PDE5 inhibitors with a specific focus on tadalafil. It includes details of the role of the nitric oxide (NO)-cyclic guanosine monophosphate (cGMP) – PDE5 pathway in the LUT organs (bladder and prostate) in addition to the available data on tadalafil in patients with LUTS secondary to BPH with or without erectile dysfunction (ED).

Expert opinion: Preclinical and clinical data have clearly demonstrated that PDE5 inhibitors induce bladder and prostate relaxation, which contributes to the improvement seen in storage symptoms in both animal models of bladder and prostate hypercontractility. Tadalafil is effective both as a monotherapy and add-on therapy in patients with LUTS secondary to BPH. Furthermore, as LUTS-BPH and ED are urological disorders that commonly coexist in aging men, tadalafil is more advantageous than α1-adrenoceptors and should be used as the first option. Tadalafil is a safe and tolerable therapy and unlike α1- adrenoceptors and 5-alpha reductase inhibitors, which can cause sexual dysfunctions, tadalafil improves sexual function.     

Neuroprotective effects of tadalafil on gerbil dopaminergic neurons following cerebral ischemia

Impairment of dopamine function, which is known to have major effects on behaviors and cognition, is one of the main problems associated with cerebral ischemia. Tadalafil, a long-acting phosphodiesterase type-5 inhibitor, is known to ameliorate neurologic impairment induced by brain injury, but not in dopaminergic regions. We investigated the neuroprotective effects of treatment with tadalafil on cyclic guanosine monophosphate level and dopamine function following cerebral ischemia. Forty adult Mongolian gerbils were randomly and evenly divided into five groups (n = 8 in each group): Sham-operation group, cerebral ischemia-induced and 0, 0.1, 1, and 10 mg/kg tadalafil-treated groups, respectively. Tadalafil dissolved in distilled water was administered orally for 7 consecutive days, starting 1 day after surgery. Cyclic guanosine monophosphate assay and immunohistochemistry were performed for thyrosine hydroxylase expression and western blot analysis for dopamine D₂ receptor expression. A decrease in cyclic guanosine monophosphate level following cerebral ischemia was found with an increase in thyrosine hydroxylase activity and a decrease in dopamine D₂ receptor expression in the striatum and substantia nigra region. However, treatment with tadalafil increased cyclic guanosine monophosphate expression, suppressed thyrosine hydroxylase expression and increased dopamine D₂ receptor expression in the striatum and substantia nigra region in a dose-dependent manner. Tadalafil might ameliorate cerebral ischemia-induced dopaminergic neuron injury. Therefore, tadalafil has the potential as a new neuroprotective treatment strategy for cerebral ischemic injury.     

Role of Serum High-Sensitivity C-Reactive Protein as a Predictor of Therapeutic Response to Tadalafil in Patients With Erectile Dysfunction: A Prospective Observational Study

IntroductionHigh-sensitivity C-reactive protein (hs-CRP), a marker of inflammation, is known to be elevated in patients with erectile dysfunction (ED). However, its role in predicting therapeutic response to phosphodiesterase-5 inhibitors is incompletely understood.AimThe aim of this study was to understand the relationship among hs-CRP, mechanism of ED, and therapeutic response of ED to tadalafil, a phosphodiesterase-5 inhibitor.MethodsA total of 282 men (mean age 36.6 ± 12.0 years) with ED were included. All subjects underwent detailed evaluation, including estimation of a 6-item abbreviated version of the International Index of Erectile Function (IIEF-6) score, penile Doppler studies, and measurement of hs-CRP. IIEF-6 scoring and hs-CRP measurement were repeated after 6 weeks of tadalafil therapy (10 mg/day). The patients were categorized into vasculogenic and nonvasculogenic ED groups based on penile Doppler findings.Main Outcome MeasureThe main outcome measure was the therapeutic response to tadalafil, in relation to the mechanism of ED and hs-CRP levels.ResultsVasculogenic ED was much less common (23.8% of the subjects) than non-vasculogenic ED. Subjects with vasculogenic ED were older, had higher prevalence of cardiovascular risk factors, had more severe (mean IIEF-6 score 9.2 ± 4.6 vs 14.8 ± 4.7; P < .001) and longer duration ED, and responded less favorably to therapy (response rate 10.4% vs 75.0%; P < .001). Those showing improvement with tadalafil had lower hs-CRP at baseline (median 1.5 mg/L [interquartile range 0.9?2.3] vs 2.0 mg/L [interquartile range 1.1?3.1; P = .034]) and had proportionately greater reduction in its level. However, on multivariate analysis, only shorter duration of ED (P = .008), non-vasculogenic origin (P = .025), and higher IIEF-6 score at baseline (P = .013) were independent predictors of response to treatment.Clinical ImplicationsSerum hs-CRP is elevated in patients who are less likely to respond to vasodilator therapy but does not have an independent predictive value for this purpose.Strengths & LimitationsThis is the largest study to evaluate the relationship among the mechanism of ED, serum hs-CRP level, and therapeutic response of ED to tadalafil. All patients underwent a penile Doppler study to characterize the type of ED. The limitations were nonrandomized nature of the study and nearly 22% dropout rate.ConclusionSerum hs-CRP level is higher in vasculogenic ED compared with non-vasculogenic ED, and is associated with poorer response to tadalafil therapy. However, this association is not independent of underlying risk factors and mechanism of ED.Jamaluddin, Bansal M, Srivastava GK, et al. Role of Serum High-Sensitivity C-Reactive Protein as a Predictor of Therapeutic Response to Tadalafil in Patients With Erectile Dysfunction: A Prospective Observational Study. J Sex Med 2019;16:1912–1921.     

Physicochemical properties of tadalafil solid dispersions – Impact of polymer on the apparent solubility and dissolution rate of tadalafil

To improve solubility of tadalafil (Td), a poorly soluble drug substance (3 μg/ml) belonging to the II class of the Biopharmaceutical Classification System, its six different solid dispersions (1:1, w/w) in the following polymers: HPMC, MC, PVP, PVP-VA, Kollicoat IR and Soluplus were successfully produced by freeze-drying. Scanning electron microscopy showed a morphological structure of solid dispersions typical of lyophilisates. Apparent solubility and intrinsic dissolution rate studies revealed the greatest, a 16-fold, increase in drug solubility (50 μg/ml) and a significant, 20-fold, dissolution rate enhancement for the Td/PVP-VA solid dispersion in comparison with crystalline Td. However, the longest duration of the supersaturation state in water (27 μg/ml) over 24 h was observed for the Td solid dispersion in HPMC. The improved dissolution of Td from Td/PVP-VA was confirmed in the standard dissolution test of capsules filled with solid dispersions. Powder X-ray diffraction and thermal analysis showed the amorphous nature of these binary systems and indicated the existence of dispersion at the molecular level and its supersaturated character, respectively. Nevertheless, as evidenced by film casting, the greatest ability to dissolve Td in polymer was determined for PVP-VA. The crystallization tendency of Td dispersed in Kollicoat IR could be explained by the low T_g (113 °C) of the solid dispersion and the highest difference in Hansen solubility parameters (6.8 MPa^0.5) between Td and the polymer, although this relationship was not satisfied for the partially crystalline dispersion in PVP. Similarly, no correlation was found between the strength of hydrogen bonds investigated using infrared spectroscopy and the physical stability of solid dispersions or the level of supersaturation in aqueous solution.     

Inhibitory effects of sildenafil and tadalafil on inflammation,oxidative stress and nitrosative stress in animal model of bronchial asthma

BackgroundCyclic neucleotides are involved in many cellular functions including smooth muscle relaxation, inflammation, and signal transduction. Sildenafil and tadalafil are phosphodiesterase-5 (PDE-5) inhibitors which prevent the degradation of cyclic neucleotide i.e. guanosine 3′,5′ cyclic monophosphate (cGMP) and increase the levels of cGMP. In this study sildenafil and tadalafil were evaluated for their anti-inflammatory, anti-oxidative and anti-nitrosative stress potential in animal model of bronchial asthma.MethodsWistar rats were sensitized with 10 mg intraperitoneal (ip) ovalbumin adsorbed to 10 μg of aluminum hydroxide on day 0. Animals were given sildenafil (1 and 3 mg/kg ip) and tadalafil (1 and 3 mg/kg ip) from day 1 to day 14. Also, on day 14 animals were challenged with ovalbumin (1 mg ip). After 24 h, samples were collected to analyze interleukin-4 (IL-4) and tumour necrosis factor-α (TNF-α), in serum and bronchoalveolar lavage fluid (BALF). The oxidative stress markers malondialdehyde (MDA), reduced glutathione (GSH) and nitric oxide metabolites (NO_x) were also measured in serum.ResultsPre-treatment with sildenafil (1 and 3 mg/kg ip) and tadalafil (1 and 3 mg/kg ip) significantly reduced the levels of pro-inflammatory cytokines IL-4 and TNF-α in rat serum and BALF. In addition, pre-treatment with both the drugs decreased the levels of MDA and NO_x and increased the levels of GSH in serum.ConclusionsSildenafil and tadalafil decreased pro-inflammatory cytokines in serum and BALF. Both drugs inhibit oxidative and nitrosative stress in animal model of bronchial asthma and could have a therapeutic potential in bronchial asthma.     

液相色谱-质谱联用同时测定西洋参制剂中人参皂苷Rg1、Re、Rb1及抗疲劳类非法添加含量

目的 建立同时测定西洋参制剂中人参皂苷Rg1、Re、Rb1及抗疲劳类非法添加含量的液相色谱-质谱联用方法.方法采用Agilent ZORBAX SB-C18色谱柱（3.0mm×150mm,3.5μm）,流动相A为含0.1%乙酸的20mmol·L-1乙酸铵溶液,流动相B为甲醇∶乙腈（3：2）的混合溶液,采用线性梯度洗脱;流速为200μL·min-1,柱温35℃.质谱条件采用电喷雾离子化（ESI）方式,正负离子模式,以多级反应监控（MRM）模式对西地那非、伐地那非、他达拉非、人参皂苷Rg1、Re和Rb1进行含量测定.结果 西地那非、伐地那非、他达拉非、人参皂苷Rg1、Re和Rb1分别在2.99～59.85,0.43～8.60,3.32～66.42,3.16～63.29,2.63～52.68,4.15～82.93μg·mL-1浓度范围内与峰面积呈良好线性关系.西洋参制剂中西地那非、伐地那非、他达拉非、人参皂苷Rg1、Re和Rb1的平均加样回收率均介于92.9%～103.3%之间.结论 本法简单、快速、灵敏、准确,可用于西洋参制剂中西地那非、伐地那非、他达拉非、人参皂苷Rg1、人参皂苷Re和Rb1含量测定,为该药的质量控制提供依据.     

他达拉非不同治疗方案对手淫取精困难患者的临床研究

目的比较他达拉非不同治疗方案对手淫取精困难患者的临床效果。方法选取本中心2012年1月~2013年5月收治的取精困难患者48例,将患者分为A、B组,每组各24例。A组患者取卵前1个月每日给予5 mg他达拉非,B组患者取卵日给予20 mg他达拉非。两组患者在取卵前1个月均配合手淫取精训练。比较两组患者取卵当日的取精成功率。结果 A组成功取精17例,取精成功率为70.83%,B组成功取精10例,取精成功率为41.67%,两组比较,差异有统计学意义（P=0.042）。结论对于取精困难患者,长期小剂量他达拉非治疗联合手淫取精训练可有效提高其取卵当日的取精成功率。     

他达拉非联合复方玄驹胶囊对56例早泄合并ED患者的临床观察

目的:观察他达拉非联合复方玄驹胶囊对早泄合并ED患者的临床疗效。方法:将来我院男科门诊就诊的106例被确诊为早泄合并ED的患者,分成治疗组和对照组两组。治疗组56例患者给予每晚口服他达拉非5mg,同时联合复方玄驹胶囊3粒/次,3次/d,连续1个月;对照组50例患者仅给予口服复方玄驹胶囊3粒/次,3次/d,连续1个月。结果:106例患者均完成了本次临床研究,所有患者治疗1个月后,治疗组患者的阴道内射精潜伏时间(IELT)平均可延长至2.01min;对照组患者的IELT也可平均延长1.07min,两组患者经治后,IELT与治疗前相比较均有显著性的差异(P0.01),且治疗组与对照组相比较差异也有统计学意义(P0.05);两组无论是患者本人还是其伴侣性生活满意度均较治疗前显著提高(P0.01),治疗组与对照组之间差异有统计学意义(P0.05)。结论:他达拉非联合复方玄驹胶囊能提高早泄合并ED患者及其性伴侣的性生活满意度,延长患者的阴道射精潜伏时间,对早泄合并ED患者有较好的疗效。     

低剂量他达拉非联合普适泰治疗慢性前列腺炎伴性功能障碍的临床研究

目的:观察低剂量他达拉非联合普适泰治疗慢性前列腺炎伴性功能障碍的临床疗效和安全性。方法:102例诊断为慢性前列腺炎伴性功能障碍(均为勃起功能障碍合并早泄,其中还合并有射精痛23例)患者,服用他达拉非5mg,隔日1次;普适泰74mg,每日2次。共治疗12周。比较治疗前、后国际勃起功能指数-5(IIEF-5)评分、阴道内射精潜伏期以及射精痛的改善情况。结果:经过12周的治疗,勃起功能改善者89例,改善率87.3%;早泄改善者70例,有效率为68.6%;射精痛改善者15例(65.2%)。不良反应共有6例(5.9%),均为轻度或中度,未经处理即自行缓解。结论:低剂量他达拉非联合普适泰能安全、有效地改善慢性前列腺炎患者性功能,提高患者性生活质量。     

An evaluation of semen characteristics in men 45 years of age or older after daily dosing with tadalafil 20mg: results of a multicenter, randomized, double-blind, placebo-controlled, 9-month study

OBJECTIVES: Assess the effects on spermatogenesis of daily tadalafil 20mg over three spermatogenesis cycles in men >or= 45 yr. METHODS: In this double-blind, placebo-controlled, noninferiority study, healthy men (or with mild erectile dysfunction) were randomized to receive tadalafil 20mg (n=125) or placebo (n=128) for 9 mo followed by a 6-mo, treatment-free period. Semen and serum samples were provided at baseline and every 10-12 wk. The primary outcome was the proportion of subjects with >or= 50% reduction in sperm concentration at end point. Secondary outcomes included sperm concentration, number per ejaculate, motility and morphology; serum concentrations of testosterone, luteinizing and follicle-stimulating hormones; and tolerability. RESULTS: Of 253 men enrolled, 191 (75%) completed treatment phase: 2 of 96 (2.1%, placebo) and 12 of 95 (12.6%, tadalafil) subjects had >or= 50% reduction in sperm concentration. Tadalafil was noninferior to placebo because the upper 95% confidence interval for the difference in proportions of tadalafil and placebo subjects with a >or= 50% reduction in sperm concentration was 17.5%, significantly less than the prespecified noninferiority margin of 20% (p=0.015). Ninety-four percent (179 of 191) of men completed the 6-mo, treatment-free period: Baseline sperm concentration levels were restored in 8 of 12 (tadalafil) and 1 of 2 (placebo) men. There were no significant differences between groups in secondary end points. Common treatment-emergent adverse events were headache, back pain, dyspepsia, gastroesophageal reflux disease, and myalgia. Twelve (9.6%) tadalafil and seven (5.5%) placebo subjects discontinued because of adverse events. CONCLUSIONS: This study demonstrated no deleterious effects of 9 mo of daily tadalafil 20mg on spermatogenesis or hormones related to testicular function in men >or= 45 yr.