Side-effect profile of sildenafil citrate (Viagra) in clinical practice

Drug Self-Aggregation into Nano-Entities Has the Potential to Induce Immune Responses

The free-state solution behaviors of small molecules profoundly affect their respective properties. It is becoming more obvious that compounds can adopt a three-phase equilibrium when placed in an aqueous solution, among soluble-lone molecule form, self-assembled aggregate form (nano-entities), and solid precipitate form. Recently, correlations have emerged between the existence of self-assemblies into drug nano-entities and unintended side effects. This report describes our pilot study involving a selection of drugs and dyes to explore if there may be a correlation between the existence of drug nano-entities and immune responses. We first implement practical strategies for detecting the drug self-assemblies using a combination of nuclear magnetic resonance (NMR), dynamic light scattering (DLS), transmission electron microscopy (TEM), and confocal microscopy. We then used enzyme-linked immunosorbent assays (ELISA) to monitor the modulation of immune responses on two cellular models, murine macrophage and human neutrophils, upon exposure to the drugs and dyes. The results suggest that exposure to some aggregates correlated with an increase in IL-8 and TNF-α in these model systems. Given this pilot study, further correlations merit pursuing on a larger scale given the importance and potential impact of drug-induced immune-related side effects.

Combinatory Approaches Targeting Cognitive Impairments and Memory Enhancement: A Review

The objective of this paper is to look at how natural medicines can improve cognition and memory when used with sildenafil, a popular erectile dysfunction medicine that also has nootropic properties. Newer treatment strategies to treat the early stages of these diseases need to be developed. Multiple factors lead to complex pathophysiological conditions, which are responsible for various long-term complications. In this review, a combination of treatments targeting these pathologies is discussed. These combinations may help manage early and later phases of cognitive impairments. The purpose of this article is to discuss a link between these pathologies and a combinational approach with the objective of considering newer therapeutic strategies in the treatment of cognitive impairments. The natural drugs and their ingredients play a major role in the management of disease progression. Additionally, their combination with sildenafil allows for more efficacy and better response. Studies showing the effectiveness of natural drugs and sildenafil are mentioned, and how these combinations could be beneficial for the treatment of cognitive impairments and amnesia are summarised. Furthermore, preclinical and clinical trials are required to explore the medicinal potential of these drug combinations.

Analyzing the Clinical Efficacy of a Type 5 Phosphodiesterase Inhibitor Combined With Ziyin Baihuo Granules in the Treatment of Erectile Dysfunction

The study explored the clinical efficacy of a type 5 phosphodiesterase inhibitor (PDE5i) combined with Ziyin Baihuo granules in the treatment of patients suffering from erectile dysfunction (ED) with yin deficiency and fire-hyperactivity syndrome. A total of 163 patients with erectile dysfunction were divided into observation and control groups. The observation group took tadalafil (Cialis) and Ziyin Baihuo granules orally, and the control group took only tadalafil orally, for 12 weeks. An additional 40 healthy people were selected as a normal group for comparison of the sex hormone levels before and after treatment of the participants in the erectile dysfunction group. After treatment, the symptoms of dry throat and tongue, tidal fever and night sweats, liking cold and avoiding heat, and waist pain showed significant improvement in the observation group (p < .05). Compared with before treatment, the clinical indexes of erectile function in the control group and the observation group were improved after treatment (p < .05). After treatment, Ziyin Baihuo granules combined with tadalafil restored the abnormal indexes of blood (p < .05) in the observation group. Our research shows that PDE5i combined with Ziyin Baihuo granules could effectively improve erectile function.

The effect of dobutamine on ocular blood flow of healthy adults: A 3D pseudocontinuous aterial spin labelling study

Purpose: Ocular blood flow (OBF) is an important risk factor for incidence, prevalence and progression of some ocular disorders. To date, there are very limited therapeutic options to increase OBF. This study investigated the effect of dobutamine on OBF of heathy adults using 3D pseudocontinuous arterial spin labelling (3D-pcASL), and explored the risk factors associated with OBF.

Methods: Forty-three healthy participants (86 eyes) were given an intravenous injection of dobutamine. We measured OBF using 3D-pcASL with a 3.0T- MRI scanner, OBF values were independently obtained by two doctors from the OBF map. We also collected physiological parameters using a vital signs monitor. The OBF and physiological parameters in the in the period before and after dobutamine injection states were obtained.

Results: OBF increased significantly after dobutamine injection using paired t test method (from 22.43 ± 9.87 to 47.73 ± 14.02 ml/min/100g, p &lt; 0.001). Age, heart rate and systolic blood pressure were the main risk factors affecting OBF using logistic regression analysis (all p values &lt; 0.05).

Conclusion: To the best of our knowledge, this is the first study observing the effect of dobutamine on OBF. Our findings indicated that intravenously injected dobutamine increased OBF, making it a possible option to counteract ocular vascular ischaemia in the future.

Evaluating the quality of asynchronously- versus synchronously-delivered virtual care: Differences in rates of reported medication side effects among patients with erectile dysfunction on a direct-to-consumer telehealth platform

Background

Asynchronous health care encounters are becoming an increasingly mainstream form of telehealth. While synchronous phone or video visits have become more widely accepted, US policymakers and other key health care stakeholders have been hesitant to fully embrace asynchronous diagnosis and treatment. This is particularly true in the context of direct-to-consumer (DTC) platforms, where encounters are patient-initiated and there is no preestablished relationship with a provider. This hesitation is compounded by limited research comparing outcomes between asynchronous and synchronous care, especially in the DTC context.

Objective

The purpose of this study was to explore whether asynchronous care leads to different patient outcomes in the form of medication-related adverse events when compared to synchronous virtual care.

Methods

Using 10,000 randomly sampled patient records from a prominent US-based DTC platform, we analyzed the rates of patient-reported side effects from commonly prescribed erectile dysfunction medications and compared these rates across modalities of treatment.

Results

Asynchronous care resulted in lower but nonsignificant differences in the rates of the reported drug-related side effects compared to synchronous treatment.

Conclusions

In some circumstances, such as treatment for erectile dysfunction, asynchronous care can offer the same level of safety in prescribing when compared to synchronous care. More research is needed to evaluate the safety of asynchronous care across a wider set of conditions and measures.

Eco-friendly stability-indicating RP-HPTLC method for sildenafil analysis, characterization and biological evaluation of its oxidized stress degradation product

A feasible and cost effective reverse-phase high-performance thin layer chromatography (RP-HPTLC) based method was developed for the quantification of sildenafil (SLD) using eco-friendly EtOH:H2O (9.5:0.5 v/v) as mobile phase. SLD was subjected to stress conditions according to the International Conference on Harmonization (ICH) guidelines. The drug undergoes significant structural changes under oxidative stress condition to the N-oxide derivative. The oxidation product Sildenafil N-oxide (SDL N-oxide) designated in the European Pharmacopeia (EP) as impurity B was characterized utilizing 1D- and 2D-NMR as well as High Resolution Electrospray Ionization Mass Spectroscopy. The aphrodisiac potency of SDL N-oxide in comparison with SLD was evaluated in vivo using rats as experimental animal model. The evaluation based on the following parameters: mount, intromission and ejaculation latencies (ML, IL and EL, respectively), mounting and intromission frequencies (MF and IF, respectively), and postejaculatory interval (PEI). SLD N-oxide expressed similar aphrodisiac effect to SLD but with less potency. Molecular docking of SDL N-oxide along with the parent drug SLD, indicated a strong binding affinity and similar binding pattern within the active site of phosphodiesterase 5 (PDE5). However, the docking score of SLD N-oxide was slightly lower as compared to SLD in agreement with the biological study findings.

Medicinal plants as a potential source of Phosphodiesterase-5 inhibitors: A review

ETHNOPHARMACOLOGICAL RELEVANCE

The prevalence and distress caused by erectile dysfunction (ED) to both male and female partners are increasing at a steady rate. ED has now become the most treated sexual disorder for men among young and old age groups due to varying physical and psychological factors. The treatment with synthetic Phosphodiesterase-5 (PDE5) inhibitors are cost-effective but due to adverse effects such as priapism, loss of vision, heart attack and syncope, the daily life patterns of these patients are distressed and hence the need for alternative medicaments or sources are of utmost important. Therefore, the exploration of medicinal plants as PDE5 inhibitors will be worthwhile in tackling the problems as many plant extracts and fractions have been long used as aphrodisiacs and sexual stimulants which may be found to be active against PDE5 enzyme.

AIM OF THE STUDY

To provide a review on the different medicinal herbs traditionally used as natural aphrodisiacs, libido or sexual enhancers which are proven for their PDE5 inhibitory effect.

MATERIALS AND METHODS

Ethnobotanical and scientific information was procured, reviewed and compiled from the literature search of electronic databases and search engines.

RESULTS

A total of 97 medicinal plants exhibiting PDE5 inhibitory effect are reviewed in this paper which is supported by preclinical experimental evidence. Among them, 77 plants have been selected according to their traditional and ethnobotanical uses as aphrodisiacs and the rest are screened according to their effectiveness against predisposing factors responsible for ED and sexual dysfunction such as diabetes and hypertension or due to the presence of phytochemicals having structural similarity towards the identified natural PDE5 inhibitors. In addition, sixteen alkaloids, sixty-one phenolics and eight polycyclic aromatic hydrocarbons have been isolated or identified from active extracts or fractions that are exhibiting PDE5 inhibitory activity. Among them, isoflavones and biflavones are the major active constituents responsible for action, where the presence of prenyl group for isoflavones; and the methoxy group at C-5 position of flavones are considered essential for the inhibitory effect. However, the prenylated flavonol glycoside, Icariin and Icariside II isolated from Epimedium brevicornum Maxim (hory goat weed) are the most effective inhibitor, till date from natural sources. Traditional medicines or formulations containing extracts of Ginkgo biloba L., Kaempferia parviflora Wall. ex Baker, Clerodendrum colebrookianum Walp., Eurycoma longifolia Jack and Vitis vinifera L. are also found to be inhibitors of PDE5 enzyme.

CONCLUSION

The review suggests and supports the rational use of traditional medicines that can be further studied for the development of potential PDE5 inhibitors. Many traditional medicines are still used in various regions of Africa, Asia and South America that are poorly characterized and experimented. Despite the availability of a vast majority of traditional formulations as aphrodisiacs or sexual stimulants, there exists a need for systemic evaluation on the efficacy as well as the mechanism of action of the herbal constituents for the identification of novel chemical moieties that can be further developed for maximum efficacy.

Erectile dysfunction after robotic radical prostatectomy: Real-life impact of vacuum erection device clinic

Introduction:

Post-radical prostatectomy erectile dysfunction (post-RPED) is a common and potentially devastating complication. The role of PDE5-inhibitors (PDE5-Is) in post-RPED is controversial and invasive pharmacological treatments are associated with poor long-term compliance. Vacuum erection devices (VEDs) are a non-pharmacological alternative. Little data regarding VED efficacy and associated patient satisfaction in post-RPED exists. This study aimed to investigate the outcomes of VED therapy in a post-robot assisted radical prostatectomy (post-RARP) population.

Methods:

All men who underwent RARP at a single centre between February 2015 and October 2017 attended a nurse-led holistic-needs-assessment (HNA) appointment at 10 weeks post-RARP. All men identifying ED as a concern at HNA were offered dedicated nurse-led post-RPED clinic and VED clinic appointments. A cross-sectional survey of patient reported outcomes in these men was performed.

Results:

In total 137/539 (25%) men reported ED as a concern at HNA. All 137 men attended the VED clinic, 124/137 (90%) responded to the survey. Commonest reason for choosing VED therapy was for combined psychological, penetration and lengthening purposes (48%). Median time from RARP to VED clinic and from VED clinic to survey was 122 days (range 56–595) and 462 days (range 66–932) respectively. At survey 88/124(70.9%) reported continued use of VED, 69/88 (78%) of this group perceived VED treatment to be successful. Of those who had stopped using VED, 7/36 (19%) felt it had been successful. Key reasons for discontinuation were either because men felt it ineffective (13/36 (37%)) or disliked the device (10/36 (29%)).

Conclusion:

VED therapy is an effective treatment for men with post-RARP ED that is well tolerated with good short- to medium-term compliance. Up to two-thirds of men may find overall satisfaction with their post-RPED after VED therapy. Level of Evidence: 3

Therapeutic Potential of Phosphodiesterase Inhibitors against Neurodegeneration: The Perspective of the Medicinal Chemist

Increasing human life expectancy prompts the development of novel remedies for cognitive decline: 44 million people worldwide are affected by dementia, and this number is predicted to triple by 2050. Acetylcholinesterase and N-methyl-d-aspartate receptors represent the targets of currently available drugs for Alzheimer’s disease, which are characterized by limited efficacy. Thus, the search for therapeutic agents with alternative or combined mechanisms of action is wide open. Since variations in 3′,5′-cyclic adenosine monophosphate, 3′,5′-cyclic guanosine monophosphate, and/or nitric oxide levels interfere with downstream pathways involved in memory processes, evidence supporting the potential of phosphodiesterase (PDE) inhibitors in contrasting neurodegeneration should be critically considered. For the preparation of this Review, more than 140 scientific papers were retrieved by searching PubMed and Scopus databases. A systematic approach was adopted when overviewing the different PDE isoforms, taking into account details on brain localization, downstream molecular mechanisms, and inhibitors currently under study, according to available in vitro and in vivo data. In the context of drug repurposing, a section focusing on PDE5 was introduced. Original computational studies were performed to rationalize the emerging evidence that suggests the role of PDE5 inhibitors as multi-target agents against neurodegeneration. Moreover, since such compounds must cross the blood–brain barrier and reach inhibitory concentrations in the central nervous system to exert their therapeutic activity, physicochemical parameters were analyzed and discussed. Taken together, literature and computational data suggest that some PDE5 inhibitors, such as tadalafil, represent promising candidates.

In vitro fertilization add-ons for the endometrium: it doesn't add-up

The probability of live birth from an in vitro fertilization (IVF) cycle is modest. Many additional treatments (add-ons) are available which promise to improve the success of IVF. This review summarizes the current evidence for common IVF add-ons which are suggested to improve endometrial receptivity. Systematic reviews of randomized controlled trials and individual trials were included. Five add-ons were included: immune therapies, endometrial scratching, endometrial receptivity array, uterine artery vasodilation, and human chorionic gonadotropin instillation. The results suggest there is no robust evidence that these add-ons are effective or safe. Many IVF add-ons are costly, consuming precious resources which may be better spent on evidence-based treatments or further IVF. Large randomized controlled trials and appropriate safety assessment should be mandatory before the introduction of IVF add-ons into routine practice.

At-line LC-QTOF-MS micro-fractionation of Derris scandens (Roxb.) Benth, coupled to radioassay for the early identification of PDE5A1 inhibitors

INTRODUCTION

Chromatographic techniques coupled with bioassays are popularly used for the detection of bioactive compounds in natural products. In this study phytochemicals responsible for showing Phosphodiesterase type 5 (PDE5) inhibitory activity in Derris scandens were studied using at-line method.

OBJECTIVE

The objective of this study was to develop an at-line liquid chromatography quadrupole time-of-flight mass spectrometry (LC-QTOF-MS) micro-fractionation method for rapid separation and identification of PDE5A1 inhibitors in 95% ethanolic extract of D. scandens.

METHODOLOGY

Initially, the correlation between LC-MS and PDE5A1 inhibitory activity was studied using three concentrations of 1:1 mixture of sildenafil and derrisisoflavone A; PDE5A1 inhibitors. The mixture was separated by high-performance liquid chromatography (HPLC) column and the eluent was split into two flows in the ratio of 1:9. The major part was collected in a 96-well plate, in each well consecutively every 30 s. The minor part was fed into an electrospray ionisation (ESI)-QTOF-MS system. After subsequent solvent removal, the collected micro-fractions were subjected to radioassay to determine PDE5A1 inhibition.

RESULTS

The result showed, PDE5A1 inhibitory activities of the micro-fractions were observed in a dose response manner and found to be in agreement with an off-line study. Similarly, 95% ethanolic extract of D. scandens was subjected to the at-line LC-QTOF-MS micro-fractionation developed, resulting in separation and tentative identification of 25 compounds with PDE5A1 inhibitory activity. Most of the compounds contained prenylated isoflavone skeleton. Additionally, the active micro-fractions also showed selectivity on PDE5A1 over PDE6 and PDE1B.

CONCLUSION

Our results demonstrated that the at-line coupled LC-QTOF-MS micro-fractionation with PDE5A1 inhibitory assay is a valuable tool for identifying PDE5A1 inhibitors from complex extracts.

Effect of amlodipine on blood flow of preovulatory follicle in women with clomiphene resistant polycystic ovaries: a randomized controlled trial

OBJECTIVE

To detect whether amlodipine could increase pre-ovulatory follicular blood flow, thus enhancing ovulation and creating a better chance of conception in women with PCOS.

METHODS

165 women were screened of which 124 were qualified and women were equally randomized to 62 receiving clomiphene citrate and amlodipine and 62 receiving clomiphene citrate and placebo. The primary outcome was to detect if amlodipine can improve pre-ovulatory follicle blood flow studied by colour and power Doppler Pulsatility index of ovarian arteries, with drug administration. The secondary outcomes were endometrial thickness and clinical pregnancy.

RESULTS

The mean value of the ovarian arteries Pulsatility Index was significantly lower in the amlodipine group when compared to those of the placebo group (1.36 and 1.82, respectively, with P value 0.002). Mean endometrial thickness, for all women in both groups, on the day of detecting a mature follicle was significantly higher in the amlodipine group compared to the placebo group (8.99 and 7.0, respectively, with P value 0.003), and clinical pregnancy increased from 11% to 37% in the amlodipine group compared to the placebo group.

CONCLUSION

Amlodipine improves ovarian blood flow and increases the chances of conception.

TRIAL REGISTRATION

Pan African Clinical Trial Registry (http://www.pactr.org). Trial No: PAC TR201708002485292.

Subarachnoid haemorrhage following first use of Sildenafil

Level of evidence: Not applicable for this case report.

Effects of sildenafil and calcitonin gene-related peptide on brainstem glutamate levels: a pharmacological proton magnetic resonance spectroscopy study at 3.0 T

BACKGROUND

Studies involving human pharmacological migraine models have predominantly focused on the vasoactive effects of headache-inducing drugs, including sildenafil and calcitonin gene-related peptide (CGRP). However, the role of possible glutamate level changes in the brainstem and thalamus is of emerging interest in the field of migraine research bringing forth the need for a novel, validated method to study the biochemical effects in these areas.

METHODS

We applied an optimized in vivo human pharmacological proton (¹H) magnetic resonance spectroscopy (MRS) protocol (PRESS, repetition time 3000 ms, echo time 37.6-38.3 ms) at 3.0 T in combination with sildenafil and CGRP in a double-blind, placebo-controlled, randomized, double-dummy, three-way cross-over design. Seventeen healthy participants were scanned with the ¹H-MRS protocol at baseline and twice (at 40 min and 140 min) after drug administration to investigate the sildenafil- and CGRP-induced glutamate changes in both brainstem and thalamus.

RESULTS

The glutamate levels increased transiently in the brainstem at 40-70 min after sildenafil administration compared to placebo (5.6%, P = 0.039). We found no sildenafil-induced glutamate changes in the thalamus, and no CGRP-induced glutamate changes in the brainstem or thalamus compared to placebo. Both sildenafil and CGRP induced headache in 53%-62% of participants. We found no interaction in the glutamate levels in the brainstem or thalamus between participants who developed sildenafil and/or CGRP-induced headache as compared to participants who did not.

CONCLUSIONS

The transient sildenafil-induced glutamate change in the brainstem possibly reflects increased excitability of the brainstem neurons. CGRP did not induce brainstem or thalamic glutamate changes, suggesting that it rather exerts its headache-inducing effects on the peripheral trigeminal pain pathways.

Audiometry results and TEOAE and DPOAE amplitudes in men taking a phosphodiesterase type 5 inhibitor for erectile dysfunction

We conducted a prospective study of transient evoked otoacoustic emissions (TEOAEs) and distortion-product otoacoustic emissions (DPOAEs) in men who were taking an oral phosphodiesterase type 5 (PDE5) inhibitor for erectile dysfunction. Our study group was made up of 30 men (60 ears), aged 34 to 60 years (mean: 50.9). They were randomly divided into three groups; 10 men were given sildenafil (Viagra) at 50 mg twice a week, 10 were given tadalafil (Cialis) at 20 mg twice a week, and 10 were given vardenafil (Levitra) at 20 mg twice a week. All patients took their drug for 3 weeks, for a total of 6 tablets for each patient. Audiometric tests and TEOAE and DPOAE measurements were performed before and after treatment. Post-treatment audiometry demonstrated improvement in hearing in all three groups. However, post-treatment TEOAE amplitudes and DPOAE amplitudes differed among the three groups; they were significantly higher in the sildenafil group at 1.0 kHz and the same in the tadalafil group; in the vardenafil group, the DPOAE amplitude was significantly lower at 3.0 kHz while there was no change in the TEOAE amplitude. We speculate that the possible mechanism for these findings is that PDE5 inhibitors block degradation of cyclic guanosine monophosphate (cGMP) and induce dilation of the cochlear microcirculation, resulting in an increase in cochlear blood flow. We also believe that the decrease in DPOAE amplitudes at 3.0 kHz seen in the vardenafil group may be related to an accumulation of nitric oxide/cGMP complex, which is toxic to the cochlea; however, since there was no change in TEOAE amplitude in the vardenafil group, this influence may be minimal. Further studies are needed to obtain a more comprehensive assessment of the effects of PDE5 inhibitors on hearing with the use of higher doses and longer durations of therapy.

The Magic Pill: The Branding of Impotence and the Positioning of Viagra as Its Solution through Edutainment

Product placement can be presented through edutainment. A drug such as Viagra is introduced or impotence is branded in movies and TV series in different ways to raise awareness of impotence disorder and Viagra as a solution. This study aims to analyze strategies of framing and branding Viagra and impotence disorder, based on a qualitative method analysis of 40 movies and TV series. Findings show that Viagra is shown as not only for older men but also for young and healthy men. Out of 40 movies and TV series in the study sample, in 14 (32.5%), the age of the target audience ranged from 20 to 40 years, in 12 (31.6%) movies and series, the age of the target audience was over 40, and in 12 (31.6%) movies and series, the target audience was very old (over 70). Viagra is shown as not only treating impotence but is presented as a wonder drug that provides a solution for psychological and social needs. The movies show usage instructions, side effects, and risks, and how to store the drug. We recommend that the viewing audience be educated for critical viewing of movies/series in order to empower viewers and give them tools for their decision-making processes concerning their health.

Physicians' response to sexual dysfunction presented by a younger vs. An older adult

AIM

The aim of this study is to determine whether physicians have an age bias regarding sexual dysfunction presented by older vs. younger patients in terms of attributed diagnosis, etiology, proposed treatment and perceived prognosis.

METHOD

An on-line survey consisting of one of two, randomly administered, case vignettes, which differed only by the age of the patient (28 or 78). In both cases, the patient was described as suffering from occasional erectile dysfunction with a clear psychosocial indication. A total of 236 physicians responded to the survey. Overall, 110 physicians received an "old" vignette and 126 physicians received a "young" vignette.

RESULTS

Even though both cases presented with a clear psychosocial etiology, the "older" vignette was more likely to be diagnosed with erectile dysfunction whereas the "younger" vignette was more likely to be diagnosed with performance anxiety. The "older" vignette's dysfunction was more likely to be attributed to hormonal changes, health problems and decreased sexual desire. Physicians were more likely to recommend testosterone replacement therapy (TRT) and PDE5 inhibitors (PDE5i; such as Sildenafil; Vardenafil; Tadalafil) as well as a referral to urology to the "older" vignette. In contrast, the "younger" vignette was more often referred to a sexologist and received a more positive prognosis than the older patient.

CONCLUSIONS

This study demonstrates an age bias among physicians regarding sexuality in later life. Of particular note is the tendency to prescribe PDE5i to the older patient, despite the clear psychosocial indication presented in the case vignette. Copyright © 2016 John Wiley & Sons, Ltd.

Daily use of sildenafil 50mg at night effectively ameliorates nocturia in patients with lower urinary tract symptoms associated with benign prostatic hyperplasia: an exploratory multicenter, double-blind, randomized, placebo-controlled study

PURPOSE

To compare the efficacy and safety of sildenafil 25 mg qd, 25 mg bid or 50 mg qd - on treating lower urinary tract symptoms with benign prostatic hyperplasia (LUTS/BPH).

MATERIALS AND METHODS

Men aged > 45 years with LUTS/BPH were randomly assigned to receive sildenafil 25 mg qd (n = 42), bid (n = 41), 50 mg qd (n = 38) or placebo (n = 41) for 8 weeks. Changes from baseline in International Prostate Symptom Score (I-PSS), maximum urinary flow rate (Qmax) and postvoid residual urine volume (PVR) were assessed at week 4 and week 8.

RESULTS

Sildenafil 25 mg qd (-7.3 ± 5.8) and 25 mg bid (-7.0 ± 5.7) exhibited significant improvements of I-PSS compared to placebo (-5.2 ± 6.4) (p = 0.020, 0.025, respectively). In particular, voiding domain was more affected than storage domain. Only sildenafil 50 mg qd improved nocturia significantly (versus placebo, p = 0.027). Quality of life score was improved in all treatment groups. Q_max and PVR did not change significantly in all groups. All regimens were well tolerated.

CONCLUSIONS

Sildenafil 25 mg qd, 25 mg bid and 50 mg qd are safe and effective to improve LUTS/BPH in long term, along with coexisting ED. In particular, nocturia is most well-controlled by 50 mg qd.

Functional and Structural Evaluation of Sildenafil in a Rat Model of Acute Retinal Ischemia/Reperfusion Injury

PURPOSE

Retinal ischemia is a common cause of visual impairment and blindness. Sildenafil, a PDE5 inhibitor which inhibits cGMP degradation and in turn prolongs the effect of nitric oxide, has been shown to be protective in a number of ischemia/reperfusion (I/R) injuries, as well as in neuronal damage. We hypothesized that treatment with sildenafil might be neuroprotective in a model of acute retinal I/R injury.

METHODS

Anterior chamber cannulation was performed to induce unilateral I/R injury in 38 Lewis rats. Animals received intraperitoneal injections of sildenafil (0.5 and 1 mg/kg once a day, for a period of 7 and 18 days, respectively), or saline. Electroretinography recordings, retinal ganglion cell (RGC) counts following retrograde labeling with fluorogold, histopathology, and immunohistochemistry (IHC) using antibodies against PDE5, NOS2, caspase-3, caspase-9, and Bcl-2 were conducted.

RESULTS

No significant differences in electroretinography, RGC counts, or retinal morphometry were observed between experimental eyes of sildenafil- and saline-treated animals. A tendency toward less necrosis in histopathology, and a slight trend toward lower PDE5, NOS2, and caspase-9 and higher Bcl-2 IHC scores were evident in experimental retinas of sildenafil-treated animals.

CONCLUSIONS

Electroretinography, RGC counts, and retinal morphometry failed to show any neuroprotective effect of sildenafil in acute retinal I/R injury in rats. A slight positive effect of sildenafil was qualitatively indicated by histopathology and IHC.

Review on a Traditional Herbal Medicine, Eurycoma longifolia Jack (Tongkat Ali): Its Traditional Uses, Chemistry, Evidence-Based Pharmacology and Toxicology

Eurycoma longifolia Jack (known as tongkat ali), a popular traditional herbal medicine, is a flowering plant of the family Simaroubaceae, native to Indonesia, Malaysia, Vietnam and also Cambodia, Myanmar, Laos and Thailand. E. longifolia, is one of the well-known folk medicines for aphrodisiac effects as well as intermittent fever (malaria) in Asia. Decoctions of E. longifolia leaves are used for washing itches, while its fruits are used in curing dysentery. Its bark is mostly used as a vermifuge, while the taproots are used to treat high blood pressure, and the root bark is used for the treatment of diarrhea and fever. Mostly, the roots extract of E. longifolia are used as folk medicine for sexual dysfunction, aging, malaria, cancer, diabetes, anxiety, aches, constipation, exercise recovery, fever, increased energy, increased strength, leukemia, osteoporosis, stress, syphilis and glandular swelling. The roots are also used as an aphrodisiac, antibiotic, appetite stimulant and health supplement. The plant is reported to be rich in various classes of bioactive compounds such as quassinoids, canthin-6-one alkaloids, β-carboline alkaloids, triterpene tirucallane type, squalene derivatives and biphenyl neolignan, eurycolactone, laurycolactone, and eurycomalactone, and bioactive steroids. Among these phytoconstituents, quassinoids account for a major portion of the E. longifolia root phytochemicals. An acute toxicity study has found that the oral Lethal Dose 50 (LD50) of the alcoholic extract of E. longifolia in mice is between 1500-2000 mg/kg, while the oral LD50 of the aqueous extract form is more than 3000 mg/kg. Liver and renal function tests showed no adverse changes at normal daily dose and chronic use of E. longifolia. Based on established literature on health benefits of E. longifolia, it is important to focus attention on its more active constituents and the constituents' identification, determination, further development and most importantly, the standardization. Besides the available data, more evidence is required regarding its therapeutic efficacy and safety, so it can be considered a rich herbal source of new drug candidates. It is very important to conserve this valuable medicinal plant for the health benefit of future generations.

Comparison of Prostaglandin E1 and Sildenafil Citrate Administration on Skin Flap Survival in Rats

Background

Alprostadil and sildenafil are known vasodilators used independently to improve flap survival in animal models. In this study, we investigate whether these agents act synergistically to decrease flap necrosis in rat models.

Methods

After acclimation period, 4 groups of 10 male white rats were given a modified McFarlane skin flap. The postoperative treatment included saline control (Group A), sildenafil citrate-only (Group B), alprostadil-only (Group C), and both sildenafil and alprostadil (Group D). The flaps were observed on postoperative days 1, 3, 5 and 7. The animals were euthenized on postoperative day 7, and the flaps were evaluated for inflammation and neovascularization.

Results

At each observation, the mean necrotic index was significantly lower for all three treatment groups (Groups A, B, C) and was the lowest for the combined treatment group. On histologic evaluations, combined treatment was associated with decreased inflammation and increased capillary vessel formation, when compared with control group.

Conclusion

Both sildenafil-only and alprostadil treatments were independently associated with increased flap survival rate. Sildenafil citrate and alprostadil had a synergistic effect in increasing flap survival rate.

Comparison of the Effects of Elaeagnus angustifolia Flower Capsule and Sildenafil Citrate Tablet on Anxiety Resulting From Sexual Dysfunction in Women Referring to the Selected Clinics of Shiraz University of Medical Sciences

Dissatisfaction from sexual relationships can result in deprivation as well as problems, such as depression, anxiety, and destruction of family’s mental health. One hundred twenty-five women (18 to 40 years) who suffered from hypoactive sexual desire disorder were divided into Elaeagnus angustifolia flower (4.5 g g daily for 35 days), sildenafil citrate tablet (50 mg for 4 weeks), and control groups. The study data were collected using the Female Sexual Function Index and Spielberger’s questionnaire and measurement of thyroid-stimulating hormone and prolactin hormone. In the Elaeagnus angustifolia group, the mean score of state and trait anxiety decreased after the intervention. In the sildenafil citrate group also, the mean score of state anxiety decreased from 22.15 ± 4.98 to 20.1 ± 5.15 ( P = .001) and that of trait anxiety decreased from 23.07 ± 4.44 to 21.55 ± 4.82 ( P = .002) after the intervention. Consumption of sildenafil citrate tablet was effective in reduction of the mean score of anxiety resulting from sexual dysfunction.

The effect of sildenafil on fascia-wrapped diced cartilage grafts

OBJECTIVES/HYPOTHESIS

Diced cartilage grafts are frequently used, especially in rhinoplasty. The effect of sildenafil on the viability of diced cartilage grafts was investigated in this study.

STUDY DESIGN

Animal experiment.

METHODS

An approximate 2 × 2-cm cartilage graft was taken from the ears of 14 New Zealand rabbits, diced to approximately 1-mm(3) dimensions, then wrapped in muscle fascia taken from the right rear leg. These were then weighed and placed in prepared cavities on the backs of the rabbits. The animals were separated into two groups, and although no procedure was applied to the control group, a daily dose of 10 mg/kg sildenafil was administered orally to the sildenafil group. After 3 months, the rabbits were sacrificed and the grafts were removed, weighed, and examined histopathologically.

RESULTS

No statistically significant difference was observed between groups with respect to graft weight. Histopathologically, graft tissue viability was 85% in the sildenafil group and 41.43% in the control group, which was determined to be statistically significant. A lower resorption rate and higher basophilia rate was observed in the sildenafil group (P < .05) compared with the control group. No statistically significant differences were determined between the groups with respect to calcification, bone metaplasia, inflammation, or fibrosis.

CONCLUSIONS

Independent of surgical technique, sildenafil may be clinically useful as a medical agent to enhance graft viability.

LEVEL OF EVIDENCE

NA

Meta-analysis of clinical efficacy of sildenafil, a phosphodiesterase type-5 inhibitor on high altitude hypoxia and its complications

OBJECTIVE

High altitude illness can be life-threatening if left untreated. Acute mountain sickness and high altitude pulmonary hypertension are two syndromes of high altitude illness. Recent clinical studies showed the beneficial effects of phosphodiesterase type 5 (PDE-5) inhibitors on the treatment of pulmonary hypertension. In this report, we performed a meta-analysis to evaluate the clinical efficacy of PDE-5 inhibitors on high altitude hypoxia and its complications.

METHODS

Randomized controlled trials evaluating the efficacy of PDE-5 inhibitor in the setting of high altitude were identified by searching Cochrane Central Register of Controlled Trials (September 2013), PubMed (from 1990 to September 2013), and EMBASE (from 1990 to September 2013). Extracted outcomes from selected studies for meta-analysis included arterial oxygen saturation, pulmonary artery systolic pressure, heart rate, and Lake Louise Consensus AMS symptom score. Weighted mean differences with 95% confidence intervals were presented for the continuous outcomes.

RESULTS

Five clinical trials that met the selection criteria were identified for the meta-analysis. All of these studies used sildenafil as the PDE-5 inhibitor. A total of 60 subjects received sildenafil, and 72 subjects were given placebo. In accordance with previous report, short-term treatment with sildenafil (1-2 days) significantly reduced pulmonary artery systolic pressure at rest (MD -4.53; 95% CI -6.72, -2.34; p<0.0001). However, treatment with sildenafil (1-2 days) did not improve oxygen saturation after exposure to high altitude (MD 0.07; 95% CI -1.26, 1.41; p=0.91). Moreover, no significant difference was observed in heart rate between sildenafil and placebo-treated group (MD 6.95; 95% CI -3.53, 17.43; p=0.19). AMS score did not improve after treatment at different time points.

CONCLUSION

Short-term treatment with sildenafil can attenuate the altitude-induced high pulmonary systolic arterial pressure, but has no significant beneficial effects on arterial oxygen saturation, heart rate, and acute mountain sickness.

Yonkenafil: a novel phosphodiesterase type 5 inhibitor induces neuronal network potentiation by a cGMP-dependent Nogo-R axis in acute experimental stroke

Yonkenafil is a novel phosphodiesterase type 5 (PDE5) inhibitor. Here we evaluated the effect of yonkenafil on ischemic injury and its possible mechanism of action. Male Sprague-Dawley rats underwent middle cerebral artery occlusion, followed by intraperitoneal or intravenous treatment with yonkenafil starting 2h later. Behavioral tests were carried out on day 1 or day 7 after reperfusion. Nissl staining, Fluoro-Jade B staining and electron microscopy studies were carried out 24h post-stroke, together with an analysis of infarct volume and severity of edema. Levels of cGMP-dependent Nogo-66 receptor (Nogo-R) pathway components, hsp70, apaf-1, caspase-3, caspase-9, synaptophysin, PSD-95/neuronal nitric oxide synthases (nNOS), brain-derived neurotrophic factor (BDNF)/tropomyosin-related kinase B (TrkB) and nerve growth factor (NGF)/tropomyosin-related kinase A (TrkA) were also measured after 24h. Yonkenafil markedly inhibited infarction and edema, even when administration was delayed until 4h after stroke onset. This protection was associated with an improvement in neurological function and was sustained for 7d. Yonkenafil enlarged the range of penumbra, reduced ischemic cell apoptosis and the loss of neurons, and modulated the expression of proteins in the Nogo-R pathway. Moreover, yonkenafil protected the structure of synapses and increased the expression of synaptophysin, BDNF/TrkB and NGF/TrkA. In conclusion, yonkenafil protects neuronal networks from injury after stroke.

Sildenafil can induce the onset of a cluster headache bout

About 25% of patients who are prescribed sildenafil, the phosphodiesterase type 5 (PDE-5) inhibitor, for erectile dysfunction (ED) experience headaches. These migraine effects are well-described, including cluster headaches. We report the case of a man who experienced a cluster headache attack following each of 2 sildenafil doses. His symptoms were resolved by adding naproxen to his treatment regimen and changing his ED treatment from 50 mg of sildenafil to 5 mg of vardenafil. To our knowledge, no study has reported cluster headaches triggered by the less commonly used PDE-5 inhibitors, namely vardenafil and tadalafil. Urologists should be cautious in prescribing sildenafil to patients with ED and with a history of cluster headaches. In these patients, they should consider prescribing low-dose vardenafil or tadalafil instead. Failure to recognize sildenafil risks could result in unnecessary headache bouts in patients with a history of cluster headaches.

Effects of Korean ginseng berry extract on sexual function in men with erectile dysfunction: a multicenter, placebo-controlled, double-blind clinical study

Ginseng is beneficial for many aspects of human physiology, including sexual function. In this study, we have evaluated the efficacy and safety of an extract of ginseng berry, which has a ginsenoside profile distinct from other parts of the plant, on sexual function in men with erectile dysfunction. In all, 119 men with mild-to-moderate ED participated in a multicenter, randomized, double-blind, parallel, placebo-controlled clinical study. They were administered 4 tablets of either standardized Korean ginseng berry (SKGB, 350 mg ginseng berry extract per tablet), or placebo, daily, for 8 weeks. Efficacy was assessed with the International Index of Erectile Function (IIEF)-15 and premature ejaculation diagnostic tool (PEDT) at the end of the 4th and 8th week. We observed that the total and each of the individual domain scores of IIEF-15 increased from 40.95 ± 7.05 to 46.19 ± 12.69 significantly in the SKGB by the 8th week (P<0.05). The erectile function domain of IIEF changed slightly from 17.17 ± 2.57 to 18.59 ± 5.99 in the SKGB group by the 8th week (P<0.05). In addition, PEDT scores significantly improved from 9.14 ± 4.57 to 7.97 ± 4.4 and 7.53 ± 4.26 in the SKGB group after 4 and 8 weeks of treatment (P<0.05). Safety markers including hormone and lipid in the blood were assessed at the end of the 4th and 8th week and they remained unchanged. Oral administration of the SKGB extract improved all domains of sexual function. It can be used as an alternative medicine to improve sexual life in men with sexual dysfunction.

Influence of sildenafil on the anticonvulsant action of selected antiepileptic drugs against pentylenetetrazole-induced clonic seizures in mice

The aim of the present study was to investigate the effect of sildenafil, a selective phosphodiesterase 5 (PDE5) inhibitor, on threshold for clonic seizures in mice. In addition, the effects of sildenafil on the anticonvulsant activity of selected antiepileptic drugs (AEDs), i.e., clonazepam (CZP), valproate (VPA), phenobarbital (PB), ethosuximide (ETS) and tiagabine (TGB), were also evaluated. The subcutaneous pentylenetetrazole (PTZ) test was used to determine the effects of sildenafil on convulsive susceptibility and the anticonvulsant activity of the studied AEDs in mice, while the acute side effects of sildenafil and its combinations with the studied AEDs were evaluated in the chimney test, step-through passive-avoidance task and grip-strength test in mice. Total brain concentrations of AEDs were also determined. Sildenafil (5–40 mg/kg) did not influence the threshold for PTZ-induced clonic seizures in mice, but increased the anticonvulsant activity of ETS in this test without any significant changes in the total brain concentration. The activity of the remaining AEDs was not significantly changed by sildenafil. Neither sildenafil alone nor its combinations with the studied AEDs produced any changes in the motor coordination, long-term memory and muscular strength in mice. Co-administration of sildenafil with ETS in male epileptic patients with co-existing erectile dysfunctions might lead to the pharmacodynamic interactions that may be beneficial for the patients. Combinations of sildenafil with CZP, VPA, PB and TGB appear to be neutral in terms of their influence on seizures.

Histopathologic results of long-term sildenafil administration on rat inner ear

OBJECTIVES

Sildenafil, a selective inhibitor of phosphodiesterase type 5, is widely used for the treatment of erectile dysfunction. Although cochlear effects of phosphodiesterase type 5 inhibitors remain still unclear because of inadequate data, some evidence that recently emerged indicates that these medications may be responsible for hearing impairment. In the present study, we aimed to examine the histopathologic effects of long-term sildenafil use on the cochlea in a rat model.

METHODS

The study was performed with adult male Wistar albino rats. The control group was fed on standard laboratory diet. The study group was applied orally with sildenafil therapy, 1.5 mg/kg once a day for 45 days. Rats were anesthetized and decapitated. Each temporal bone was dissected, and the cochleas were removed en bloc. The inner-ear biopsy specimens were examined histologically with hematoxylin and eosin and caspase 3 immunoreaction under light microscopy.

RESULTS

Hematoxylin and eosin staining showed no distinctive difference between the control group and the sildenafil group. With immunohistochemical examination, caspase 3 immunoreactivity was observed in the sildenafil group. In the control group, caspase 3 immunoreactivity was not observed.

CONCLUSIONS

The caspase 3 immunoreactivity in the sildenafil group was strongly associated with an increase in apoptotic events in the cochlea. Long-term use of sildenafil can cause hearing impairment through increased apoptosis.

Eurycoma longifolia: Medicinal Plant in the Prevention and Treatment of Male Osteoporosis due to Androgen Deficiency

Osteoporosis in elderly men is now becoming an alarming health issue due to its relation with a higher mortality rate compared to osteoporosis in women. Androgen deficiency (hypogonadism) is one of the major factors of male osteoporosis and it can be treated with testosterone replacement therapy (TRT). However, one medicinal plant, Eurycoma longifolia Jack (EL), can be used as an alternative treatment to prevent and treat male osteoporosis without causing the side effects associated with TRT. EL exerts proandrogenic effects that enhance testosterone level, as well as stimulate osteoblast proliferation and osteoclast apoptosis. This will maintain bone remodelling activity and reduce bone loss. Phytochemical components of EL may also prevent osteoporosis via its antioxidative property. Hence, EL has the potential as a complementary treatment for male osteoporosis.

Effects of sildenafil on pentylenetetrazol-induced convulsions in mice and amygdala-kindled seizures in rats

Sildenafil is the first marketed phosphodiesterase 5 inhibitor for the treatment of erectile dysfunction and recently, for pulmonary hypertension. While the treatment was found to be highly effective, several adverse effects are associated with this compound. Among numerous central nervous system-related untoward effects, proconvulsant activity was reported. The purpose of this study was to assess the effect of sildenafil on seizure threshold in rodents. Two seizure models/tests were used: the timed intravenous (iv) pentylenetetrazol (PTZ) infusion test in mice and the amygdala-kindling model in rats. Sildenafil was administered intraperitoneally 30 min before induction of seizures. In the iv PTZ paradigm, the first myoclonic twitch, generalized clonus with loss of the righting reflex, and forelimb tonus were recorded. In the amygdala-kindling model in rats, the following parameters were analyzed: threshold for induction of epileptiform discharges in the stimulated amygdala (afterdischarge threshold, ADT), seizure severity, seizure duration, and afterdischarge duration. Sildenafil (dosage range of 5-40 mg/kg) did not significantly affect the threshold for myoclonic twitches in the timed iv PTZ infusion test in mice but significantly decreased the threshold for clonic seizures at a dose of 20 mg/kg. Sildenafil at all doses tested neither significantly influenced the focal seizure threshold in the amygdala-kindling model of epilepsy in rats nor influenced seizure severity. Sildenafil significantly shortened afterdischarge duration and seizure duration recorded at the ADT current, indicative of a weak anticonvulsant activity. Our results show that sildenafil may have both pro- and anticonvulsant activity, which depends on the experimental model of epilepsy, on animal species and the dose of sildenafil. Based on these data and in view of the clinical observations, sildenafil should be used in patients suffering from epilepsy with caution and only based on a careful individual risk/benefit evaluation.

Effect of sildenafil on the anticonvulsant action of classical and second-generation antiepileptic drugs in maximal electroshock-induced seizures in mice

PURPOSE

The goal of the present study was to evaluate the effects of sildenafil on the threshold for electrically induced seizures in mice. In addition, interactions between sildenafil and classical and second-generation antiepileptic drugs (AEDs), that is, carbamazepine (CBZ), phenobarbital (PB), phenytoin (PHT), valproate (VPA), lamotrigine (LTG), topiramate (TPM), and oxcarbazepine (OXC) were evaluated.

METHODS

Two electroconvulsive tests were used: maximal electroshock seizure threshold (MEST) and maximal electroshock seizure (MES) tests in mice. Acute adverse effects of the studied combinations were investigated in the chimney test, step-through passive avoidance task, and grip-strength test. Total brain and free plasma concentrations of AEDs were also determined.

RESULTS

Sildenafil raised the threshold for electroconvulsions in a dose-dependent manner. It also increased the anticonvulsant activity of CBZ, VPA, and TPM in the MES test, whereas the activity of the remaining AEDs was not significantly changed. Sildenafil increased total brain and free (protein unbound) plasma CBZ concentrations and total brain VPA concentration. Neither sildenafil nor its coadministration with the studied AEDs affected motor coordination and long-term memory in mice. Interestingly, sildenafil dose-dependently enhanced the skeletal muscle strength in mice, although combinations of sildenafil with AEDs were ineffective in this respect.

CONCLUSIONS

Sildenafil significantly raised the threshold for electroconvulsions in mice without any impairment of motor performance and long-term memory, but it enhanced muscle strength. Treatment of patients on CBZ or VPA with sildenafil may not be recommended due to pharmacokinetic interactions. Coadministration of sildenafil with other AEDs, especially with TPM, seems to be a reasonable choice.

A review of the herbal phosphodiesterase inhibitors; future perspective of new drugs

Phosphodiesterase inhibitors (PDEIs) are a class of drugs that are widely used because of their various pharmacological properties including cardiotonic, vasodilator, smooth muscle relaxant, antidepressant, antithrombotic, bronchodilator, antiinflammatory and enhancer of cognitive function. In the recent years, interest in drugs of plant origin has been progressively increased. Some pharmacologically active substances that come from plants demonstrate PDEI activity. They mainly belong to alkaloids, flavonoids, and saponins. In this review, studies on herbal PDEI were reviewed and their possible therapeutic applications were discussed. Screening plants for PDE inhibitory activity may help to develop standardized phytotherapeutic products or find new sources for new lead structures with PDEI pharmacological activity. The studies discussed in this paper are mainly in vitro and for more reasonable and conclusive results, it is required to conduct in vivo and finally human and clinical tests.

Pharmacogenetics and pharmacogenomics of sexual dysfunction: current status, gaps and potential applications

Although treatment of different types of sexual dysfunction has improved in the past decade with the introduction of phosphodiesterase type 5 inhibitors and selective serotonin reuptake inhibitors, response rates to these targeted therapies are variable. There are a number of studies in the published literature that provide proof-of-concept that genetic variation contributes to the variable response. Pharmacogenomics will most likely be one part of our therapeutic armamentarium in the future and will provide a stronger scientific basis for optimizing drug therapy on the basis of each patient’s genetic constitution. This article will review English language medical literature on the state-of-the-art genetic polymorphisms of drug targets, transporters and signaling molecules as well as pharmacogenetic studies of sexual dysfunction and suggested possible applications. Collectively, the data demonstrate that pharmacogenomics in the field of sexual medicine is still in its infancy. More research will provide further intriguing new discoveries in years to come.

Effect of phosphodiesterase-5 inhibitor on hearing

Objective:

Following a report of sudden hearing loss in a patient taking phosphodiesterase type 5 inhibitor, and a Food and Drug Administration announcement concerning this class of drugs, a study was planned to investigate if ototoxicity occurs in patients using phosphodiesterase 5 inhibitor for erectile dysfunction.

Methods:

Eighteen patients with erectile dysfunction who had been using phosphodiesterase 5 inhibitor were included in the study. Audiometric tests were performed on all patients, between the frequencies 250 and 16 000 Hz, before and 1, 5 and 72 hours after drug ingestion.

Results:

Four patients showed a unilateral threshold decrease compatible with ototoxicity criteria; this change was reversible. A statistically significant difference in pre- versus post-drug hearing thresholds was observed in the right ear at 10 000 Hz (p = 0.008). There were no statistically significant hearing threshold differences at any other frequencies (p > 0.05).

Conclusion:

Although temporary ototoxicity was noted in four patients, we could not find any permanent, deleterious effect of phosphodiesterase type 5 inhibitor on hearing thresholds.

Effect of sildenafil citrate on interleukin-1beta-induced nitric oxide synthesis and iNOS expression in SW982 cells

The purpose of this study was to identify the effect of sildenafil citrate on IL-1beta-induced nitric oxide (NO) synthesis and iNOS expression in human synovial sarcoma SW982 cells. IL-1? stimulated the cells to generate NO in both dose- and time-dependent manners. The IL-1beta-induced NO synthesis was inhibited by guanylate cyclase (GC) inhibitor, LY83583. When the cells were treated with 8-bromo-cGMP, a hydrolyzable analog of cGMP, NO synthesis was increased upto 5-fold without IL-1beta treatment suggesting that cGMP is an essential component for increasing the NO synthesis. Synoviocytes and chondrocytes contain strong cGMP phosphodiesterase (PDE) activity, which has biochemical features of PDE5. When SW982 cells were pretreated with sildenafil citrate (Viagra), a PDE5 specific inhibitor, sildenafil citrate significantly inhibited IL-1beta-induced NO synthesis and iNOS expressions. From this result, we noticed that PDE5 activity is required for IL-1?-induced NO synthesis and iNOS expressions in human synovial sarcoma cells, and sildenafil citrate may be able to suppress an inflammatory reaction of synovium through inhibition of NO synthesis and iNOS expression by cytokines.

Effects of phosphodiesterase-5 inhibitors on sperm parameters and fertilizing capacity

The aim of this review study is to elucidate the effects that phosphodiesterase 5 (PDE5) inhibitors exert on spermatozoa motility, capacitation process and on their ability to fertilize the oocyte. Second messenger systems such as the cAMP/adenylate cyclase (AC) system and the cGMP/guanylate cyclase (GC) system appear to regulate sperm functions. Increased levels of intracytosolic cAMP result in an enhancement of sperm motility and viability. The stimulation of GC by low doses of nitric oxide (NO) leads to an improvement or maintenance of sperm motility, whereas higher concentrations have an adverse effect on sperm parameters. Several in vivo and in vitro studies have been carried out in order to examine whether PDE5 inhibitors affect positively or negatively sperm parameters and sperm fertilizing capacity. The results of these studies are controversial. Some of these studies demonstrate no significant effects of PDE5 inhibitors on the motility, viability, and morphology of spermatozoa collected from men that have been treated with PDE5 inhibitors. On the other hand, several studies demonstrate a positive effect of PDE5 inhibitors on sperm motility both in vivo and in vitro. In vitro studies of sildenafil citrate demonstrate a stimulatory effect on sperm motility with an increase in intracellular cAMP suggesting an inhibitory action of sildenafil citrate on a PDE isoform other than the PDE5. On the other hand, tadalafil's actions appear to be associated with the inhibitory effect of this compound on PDE11. In vivo studies in men treated with vardenafil in a daily basis demonstrated a significantly larger total number of spermatozoa per ejaculate, quantitative sperm motility, and qualitative sperm motility; it has been suggested that vardenafil administration enhances the secretory function of the prostate and subsequently increases the qualitative and quantitative motility of spermatozoa. The effect that PDE5 inhibitors exert on sperm parameters may lead to the improvement of the outcome of assisted reproductive technology (ART) programs. In the future PDE5 inhibitors might serve as adjunct therapeutical agents for the alleviation of male infertility.

Sildenafil in the treatment of erectile dysfunction: an overview of the clinical evidence

Erectile dysfunction (ED) is a highly prevalent disease associated with aging as well as with several risk factors including hypertension, heart disease, obesity, dyslipidemia, diabetes, hypogonadism, drugs-related, and pelvic surgery. Many of these factors are components of the metabolic syndrome, a multiplex risk factor for cardiovascular disease (CVD). ED shares common risk factors with CVD. Endothelial dysfunction seems to be the early underlying pathophysiology across both conditions. The efficacy, tolerability and cardiovascular safety of sildenafil has been evaluated in numerous large, randomized, double-blind, placebo-controlled clinical studies in the broad population of men with ED including men with several co-morbid conditions. Sildenafil is effective in several specific patient populations including the difficult-to-treat subpopulations such as diabetes mellitus and after radical prostatectomy. It is associated with rapid onset of action – within 14 minutes for some men – and an extended duration of action for up to 12 hours. Sildenafil improves quality of life and satisfaction for treated men and is well tolerated with a favorable safety profile. New data suggest that sildenafil has beneficial effects in several chronic conditions. It has been approved for the treatment of idiopathic pulmonary hypertension. Numerous articles have suggested that it improves endothelial function and a possible role on premature ejaculation or treatment of lower urinary tract symptoms has been suggested.

Nasal congestion after visual sexual stimulation with and without sildenafil (Viagra): a randomized placebo-controlled study

Sildenafil (Viagra) is a selective phosphodiesterase type 5 inhibitor (PDE5-I) approved for treatment of erectile dysfunction. Although relatively well-tolerated, sildenafil is associated with undesired effects including headache, flushing, dyspepsia, nasal congestion, and visual disturbances. In the present study we explored the impact of sildenafil on nasal airway parameters in young potent men. Eleven men (age 26.0 +/- 1.8 years) with normal BMI (25.7 +/- 0.5) and without nasal respiratory disorders were enrolled in a double-blind, crossover study. All men underwent evaluation of systolic (SBP) and diastolic blood pressure (DBP), heart rate (HR), SpO2%, acoustic rhinometry, and nasal endoscopy before and after placebo or sildenafil (50 mg) plus visual sexual stimulation (VSS). Nasal examination was performed using 0 degrees rigid telescopes, 4 mm in diameter. A Student's t test was used for direct comparisons, while the Kruskal-Wallis test (K-W) was utilized for multiple comparisons. After administration of sildenafil plus VSS, the minimum cross sectional area (MCA) was significantly lower that observed with either placebo (P = 0.03) or sildenafil alone (P = 0.003). However, the post-stimulation values did not demonstrate any significant differences among the different treatment arms (P = 0.48; DF = 2; K-W test). In contrast, endonasal volume (VOL) was significantly lower after sildenafil + VSS (P = 0.01), but not after placebo + VSS (P = 0.18). None of the other parameters monitored showed any significant variations. Rhinoscopy showed a characteristic increase of the volume of the inferior turbinates, with subjective differences between placebo and sildenafil. These preliminary results suggest that sildenafil reduces nasal volume, and that sexual stimulation may decrease nasal airflow by itself.

Repeated intracorporeal self-injection: effect on peak systolic velocity and cavernosal artery diameter

This work is aimed at evaluating the effect of repeated intracavernosal injection (ICI) self-injection on the peak systolic velocity (PSV) and the diameter of cavernosal arteries. Sixty erectile dysfunction (ED) patients who were positive responders for ICI therapy were studied. Pharmacopenile duplex ultrasonography (PPDU) was carried out before starting ICI and after 10 doses of home therapy in an open-label uncontrolled study. There was significant increase in the cavernosal artery diameter and their PSV before and after injection. Cavernosal arteries diameter before injection in both right and left sides was 0.64+/-0.13 and 0.63+/-0.12 mm at the start and became 0.81+/-0.22 and 0.79+/-0.22 mm respectively at the end with significant differences (P<0.001). Cavernosal arteries diameter after injection in both right and left sides was 1.10+/-0.18 and 1.09+/-0.19 mm at the start and became 1.34+/-0.39 and 1.27+/-0.33 mm respectively at the end with significant differences (P<0.001). PSV at the start was 33.77+/-13.26 and 32.33+/-8.09 cm/s on both right and left sides and became 44.4+/-1.19 and 46.1+/-5.86 cm/s respectively at the end with significant differences (P<0.001). It is concluded that repeated ICI improves arterial erectile response with associated increase in PSV and cavernosal artery diameters.