Randomized, Multicenter Study to Assess the Effects of Different Doses of Sildenafil on Mortality in Adults With Pulmonary Arterial Hypertension.

BACKGROUND: Sildenafil, approved for pulmonary arterial hypertension (PAH), has a recommended adult dose of 20 mg TID, with a previously approved 5-mg TID dose by the US Food and Drug Administration. Safety concerns arose because of common off-label use of higher doses, particularly after pediatric data linked higher doses to increased mortality. To assess this, the Food and Drug Administration mandated a study evaluating the effects of various sildenafil doses on mortality in adults with PAH. METHODS: This randomized, double-blind study compared sildenafil at doses of 5, 20, or 80 mg TID in adults with PAH. The primary objective was noninferiority of 80 mg of sildenafil versus 5 mg for all-cause mortality. Secondary end points included time to clinical worsening and change in 6-minute walk distance at 6 months. Interim analyses were planned at 50% and 75% of the anticipated mortality events. Safety and tolerability were assessed in the intention-to-treat population. RESULTS: The study was halted after the first interim analysis, demonstrating noninferiority for 80 mg of sildenafil versus 5 mg. Of 385 patients enrolled across all dose groups, 78 died. The primary analysis showed a hazard ratio of 0.51 (99.7% CI, 0.22-1.21; P<0.001 for noninferiority) for overall survival comparing 80 mg of sildenafil with 5 mg. Time to clinical worsening favored 80 mg of sildenafil compared with 5 mg (hazard ratio, 0.44 [99.7% CI, 0.22-0.89]; P<0.001). Sildenafil at 80 mg improved 6-minute walk distance from baseline at 6 months compared with 5 mg (least square mean change, 18.9 m [95% CI, 2.99-34.86]; P=0.0201). No significant differences were found between 80 mg of sildenafil and 20 mg in mortality, clinical worsening, and 6-minute walk distance. Adverse event-related drug discontinuations were numerically higher with 80 mg of sildenafil. CONCLUSIONS: Sildenafil at 80 mg was noninferior to sildenafil at 5 mg when examining all-cause mortality in adults with PAH. Secondary efficacy end points favored 80 mg of sildenafil over 5 mg. On the basis of these findings, the Food and Drug Administration recently revoked the approval of 5 mg of sildenafil for adults with PAH, reinforced 20 mg TID as the recommended dose, and now allows dose titration up to 80 mg TID, if needed. REGISTRATION: URL: https://www.clinicaltrials.gov; Unique identifier: NCT02060487.

Maternal tadalafil treatment does not increase uterine artery blood flow or oxygen delivery in the pregnant ewe.

Increasing placental perfusion (PP) could improve outcomes of growth-restricted fetuses. One way of increasing PP may be by using phosphodiesterase (PDE)-5 inhibitors, which induce vasodilatation of vascular beds. We used a combination of clinically relevant magnetic resonance imaging (MRI) techniques to characterize the impact that tadalafil infusion has on maternal, placental and fetal circulations. At 116-117 days' gestational age (dGA; term, 150 days), pregnant ewes (n = 6) underwent fetal catheterization surgery. At 120-123 dGA ewes were anaesthetized and MRI scans were performed during three acquisition windows: a basal state and then ∼15-75 min (TAD 1) and ∼75-135 min (TAD 2) post maternal administration (24 mg; intravenous bolus) of tadalafil. Phase contrast MRI and T2 oximetry were used to measure blood flow and oxygen delivery. Placental diffusion and PP were assessed using the Diffusion-Relaxation Combined Imaging for Detailed Placental Evaluation-'DECIDE' technique. Uterine artery (UtA) blood flow when normalized to maternal left ventricular cardiac output (LVCO) was reduced in both TAD periods. DECIDE imaging found no impact of tadalafil on placental diffusivity or fetoplacental blood volume fraction. Maternal-placental blood volume fraction was increased in the TAD 2 period. Fetal D O 2 ${D_{{{\mathrm{O}}_2}}}$ and V ̇ O 2 ${\dot V_{{{\mathrm{O}}_2}}}$ were not affected by maternal tadalafil administration. Maternal tadalafil administration did not increase UtA blood flow and thus may not be an effective vasodilator at the level of the UtAs. The increased maternal-placental blood volume fraction may indicate local vasodilatation of the maternal intervillous space, which may have compensated for the reduced proportion of UtA D O 2 ${D_{{{\mathrm{O}}_2}}}$ .

Spontaneous erectile function recovery among young men with erectile dysfunction taking tadalafil 5 mg once a day.

BACKGROUND: Daily (once a day [OaD]) tadalafil intake is a valuable option for men favoring spontaneous over scheduled sexual intercourse. AIM: The study sought to assess the rate of and the clinical factors associated with spontaneous, medication-free erectile function (EF) recovery after discontinuation of tadalafil 5 mg OaD in a cohort of young men seeking first medical help for psychogenic erectile dysfunction (ED) as their primary complaint. METHODS: Data from 96 consecutive patients <50 years of age seeking first medical help for ED and prescribed tadalafil 5 mg OaD were analyzed. Patients completed the International Index of Erectile Function (IIEF) and underwent baseline penile color Doppler ultrasound. Follow-up involved clinical assessments or phone interviews. Spontaneous medication-free EF recovery was defined as IIEF EF domain score >22 after tadalafil discontinuation, prompting cessation of follow-up. Descriptive statistics compared tadalafil OaD responders and nonresponders. Cox regression hazard models explored the association between baseline characteristics and EF recovery risk post-drug discontinuation. Kaplan-Meier analyses estimated EF recovery probability over time. OUTCOMES: The primary outcome was EF recovery after discontinuation of tadalafil 5 mg OaD. RESULTS: Overall, median age was 39 (interquartile range [IQR], 32-45) years. Of all, 82 (85.4%) patients achieved EF recovery after tadalafil OaD discontinuation, while 14 (14.6%) patients were identified as nonresponders. Median tadalafil usage time (from beginning to discontinuation) was 3 (IQR, 2-11) months. The most common treatment-emergent adverse event was headache in 9 (9.4%) patients. Nonresponders were older (43 [IQR, 42-45] years vs 38 [IQR, 31-44] years; P = .03), had higher body mass index (25.5 [IQR, 23.4-29.9] kg/m2 vs 23.6 [IQR, 21.8-25.9] kg/m2; P = .04), and reported lower baseline IIEF EF domain scores (12 [IQR, 7-15] vs 15 [IQR, 10-22]; P = .02) than responders. Nonresponders and responders did not differ in terms of baseline ED severity, Charlson comorbidity index, smoking, alcohol consumption, regular physical exercise, and color Doppler ultrasound parameters. Upon Cox regression analysis, younger age (hazard ratio, 0.95; 95% confidence interval, 0.92-0.99; P = .01) was associated to EF recovery, after adjusting for baseline ED severity, body mass index, smoking, and Charlson comorbidity index ≥1. The Kaplan-Meier analysis displays the probability of EF recovery over time, indicating rates of 43%, 60%, and 72% at 3-, 6-, and 12-month follow-up intervals, respectively. CLINICAL IMPLICATIONS: Tadalafil 5 mg OaD is an effective short-term treatment for psychogenic ED, allowing its discontinuation after achieving a normal medication-free EF. STRENGTHS AND LIMITATIONS: The main limitations are the limited number of participants and the potential neglect of confounding factors. CONCLUSION: Almost 1 out of 2 young men with primary psychogenic ED who were prescribed with tadalafil 5 mg OaD recovered spontaneous medication-free EF after 3 months of treatment. Overall, the younger the patient was, the higher the chance there was of spontaneous EF recovery after drug discontinuation.

Safety of topical sildenafil cream, 3.6% in a randomized, placebo-controlled trial for the treatment of female sexual arousal disorder.

BACKGROUND: There are currently no Food and Drug Administration-approved treatments for female sexual arousal disorder (FSAD), which is physiologically analogous to male erectile dysfunction. AIMS: The study sought to test the systemic and local genital safety of topical sildenafil cream, 3.6% (sildenafil cream) among healthy premenopausal women with FSAD and their sexual partners over a 12-week treatment period. METHODS: This was a phase 2b, exploratory, randomized, placebo-controlled, double-blind study of sildenafil cream among healthy premenopausal women with FSAD. Safety was assessed by the frequency and incidence of treatment-emergent adverse events (TEAEs) among participants and their sexual partners. Participants recorded the incidence of TEAEs in a daily eDiary (electronic diary). Sexual partners were contacted within 72 hours of each sexual event in which investigational product was used. All participants used placebo cream for 1 month, during a single-blind run-in period, and then if eligible, were randomized 1:1 to sildenafil cream or placebo cream. Participants used their assigned investigational product over a 12-week double-blind dosing period. They attended monthly follow-up visits, in which their eDiary TEAE data were reviewed by the study staff and graded for severity and relationship to study product. OUTCOMES: The frequency and incidence of TEAEs among participants and their sexual partners. RESULTS: During the 12-week double-blind dosing period, there were 78 TEAEs reported by 29 of 99 sildenafil-assigned participants and 65 TEAEs reported by 28 of 94 placebo-assigned participants (P = .76). All TEAEs were mild or moderate in severity. The most common treatment-related TEAE among active and placebo-assigned participants was application site discomfort. There were no differences in the number of treatment-related TEAEs among sildenafil cream vs placebo cream users (P > .99). Four sildenafil cream participants and 3 placebo cream participants discontinued the study due to TEAEs involving application site discomfort (P > .99). There were 9 TEAEs reported by 7 of 91 sexual partners exposed to sildenafil cream vs 4 TEAEs reported by 4 of 84 sexual partners exposed to placebo cream (P = .54). CLINICAL IMPLICATIONS: These data support further clinical development of topical sildenafil cream for the treatment of FSAD. STRENGTHS AND LIMITATIONS: Safety was assessed among participants and their sexual partners after 1357 and 1160 sexual experiences in which sildenafil cream or placebo cream were used, respectively. The phase 2b study was powered for the primary objectives of efficacy, rather than safety. CONCLUSION: These data demonstrate that topically applied sildenafil cream was safe and well tolerated by exposed users and their sexual partners.

The effect of combination treatment with low-intensity shockwave therapy and daily tadalafil on severe erectile dysfunction: a double-blind, randomized, sham-controlled clinical trial.

BACKGROUND: Patients with severe erectile dysfunction (ED) remain the most challenging group in terms of available noninvasive treatment modalities. AIM: The study sought to assess the role of combination therapy with low-intensity shockwave therapy (LiST) and daily tadalafil 5 mg in a highly select group of patients with severe vasculogenic ED through a double-blind, randomized trial. METHODS: Forty-eight sexually active men were randomly assigned to 12 sessions of LiST 3 times weekly and tadalafil 5 mg once daily (n = 34) or sham therapy and tadalafil (n = 17) for 4 weeks. Patients were assessed at 1 and 3 months after completion of treatment. OUTCOMES: Improvement of erectile function was evaluated through the International Index of Erectile Function-Erectile Function domain (IIEF-EF) or 6-item IIEF and the Sexual Encounter Profile (SEP) diary. The primary outcome was the difference between the groups in the IIEF-EF at 3 months after completion of treatment. Secondary outcomes comprised (1) the difference between the groups in the IIEF-EF at 1 month after completion of treatment, (2) the difference between the groups in the "yes" responses to question 3 of the SEP diary at 1 and 3 months, and (3) the treatment-related adverse events. The number of patients attaining a minimal clinically important difference in the IIEF-EF (improvement of at least 7 points) was also assessed. RESULTS: After treatment, the absolute scores in the IIEF-EF were higher in patients receiving LiST and tadalafil vs sham therapy and tadalafil both at the 1-month (12.1 ± 2.4 vs 10.2 ± 1.7; P = .002) and at the 3-month (12.9 ± 2.1 vs 10.8 ± 1.8; P < .001) evaluation. Between the 2 groups, the proportion of "yes" responses to question 3 of the SEP diary was not statistically significant, whereas the number of patients attaining a minimal clinically important difference in the IIEF-EF was statistically significant only at the 3-month evaluation. No adverse events occurred. CLINICAL IMPLICATIONS: Application of LiST in patients with severe vasculogenic ED receiving daily dose tadalafil may further improve erectile function compared with tadalafil as a stand-alone treatment on the short term. STRENGTHS AND LIMITATIONS: Although we provided the first study in the field, severe vasculogenic ED was defined based on medical history and clinical examination and not based on penile ultrasound measures. CONCLUSION: The combination of 12 sessions LiST 3 times weekly and daily tadalafil for 4 weeks led to a 2-point difference in the IIEF-EF compared with sham therapy and daily tadalafil among patients with severe vasculogenic ED after 1 and 3 months from completion of treatment.

Prophylactic sildenafil to prevent bronchopulmonary dysplasia: A systematic review and meta-analysis.

BACKGROUND: Bronchopulmonary dysplasia (BPD) persists as one of the foremost factors contributing to mortality and morbidity in extremely preterm infants. The effectiveness of administering sildenafil early on to prevent BPD remains uncertain. The aim of this study was to investigate the efficacy and safety of prophylactically administered sildenafil during the early life stages of preterm infants to prevent mortality and BPD. METHODS: MEDLINE, Embase, Cochrane Central Register of Controlled Trials, Cumulative Index to Nursing and Allied Health Literature, and Ichushi were searched. Published randomized controlled trials (RCTs), non-RCTs, interrupted time series, cohort studies, case-control studies, and controlled before-and-after studies were included. Two reviewers independently screened the title, abstract, and full text, extracted data, assessed the risk of bias, and evaluated the certainty of evidence (CoE) following the Grading of Recommendations Assessment and Development and Evaluation approach. The random-effects model was used for a meta-analysis of RCTs. RESULTS: This review included three RCTs (162 infants). There were no significant differences between the prophylactic sildenafil and placebo groups in mortality (risk ratio [RR]: 1.32; 95% confidence interval [CI]: 0.16-10.75; very low CoE), BPD (RR: 1.20; 95% CI: 0.79-1.83; very low CoE), and all other outcome assessed (all with very low CoE). The sample sizes were less than the optimal sizes for all outcomes assessed, indicating the need for further trials. CONCLUSIONS: The prophylactic use of sildenafil in individuals at risk of BPD did not indicate any advantageous effects in terms of mortality, BPD, and other outcomes, or increased side effects.

Risk Reduction and Hemodynamics with Initial Combination Therapy in Pulmonary Arterial Hypertension.

Rationale: An initial oral combination of drugs is being recommended in pulmonary arterial hypertension (PAH), but the effects of this approach on risk reduction and pulmonary vascular resistance (PVR) are not known.Objectives: To test the hypothesis that a low-risk status would be determined by the reduction of PVR in patients with PAH treated upfront with a combination of oral drugs.Methods: The study enrolled 181 treatment-naive patients with PAH (81% idiopathic) with a follow-up right heart catheterization at 6 months (interquartile range, 144-363 d) after the initial combination of endothelin receptor antagonist + phosphodiesterase-5 inhibitor drugs and clinical evaluation and risk assessments by European guidelines and Registry to Evaluate Early and Long-Term PAH Disease Management scores.Measurements and Main Results: Initial combination therapy improved functional class and 6-minute-walk distance and decreased PVR by an average of 35% (median, 40%). One-third of the patients had a decrease in PVR <25%. This poor hemodynamic response was independently predicted by age, male sex, pulmonary artery pressure and cardiac index, and at echocardiography, a right/left ventricular surface area ratio of greater than 1 associated with low tricuspid annular plane systolic excursion of less than 18 mm. A low-risk status at 6 months was achieved or maintained in only 34.8% (Registry to Evaluate Early and Long-Term PAH Disease Management score) to 43.1% (European score) of the patients. Adding criteria of poor hemodynamic response improved prediction of a low-risk status.Conclusions: A majority of patients with PAH still insufficiently improved after 6 months of initial combinations of oral drugs is identifiable at initial evaluation by hemodynamic response criteria added to risk scores.

Positive Predictors for Response to Ambrisentan Combination Therapy in Pulmonary Arterial Hypertension.

The AMBITION study (NCT01178073) provided the first long-term clinical evidence for initial combination therapy with ambrisentan and tadalafil in patients with pulmonary arterial hypertension (PAH). Nevertheless, predictors of treatment response were not assessed.To identify predictors for response to initial combination therapy, we examined data from 302 patients with PAH (World Health Organization Functional Class II or III) who received initial combination therapy from the modified intention-to-treat population of the AMBITION study (n = 605). A responder was defined as not having undergone a clinical failure event. Univariate and multivariate analyses were performed. Multivariate logistic regression with interactive backward selection was used to assess the independent association of potential predictors with response.Treatment responders were younger, more often female, and less likely to have comorbidities or a requirement for oxygen therapy, compared with nonresponders. At multivariate analysis, female sex (odds ratio [OR] 2.67; 95% confidence interval [CI] 1.29, 5.52; P = 0.0081), longer 6-minute walk distance (OR 1.01; 95% CI 1.00, 1.01; P = 0.0039), lower baseline log N-terminal-prohormone of brain natriuretic peptide (OR 0.70; 95% CI 0.52, 0.94; P = 0.0190), and aldosterone antagonist use (OR 2.54; 95% CI 1.03, 6.26; P = 0.0436) independently predicted response to initial combination therapy.Besides demographic factors, the absence of comorbidities and less severe disease state, and the use of aldosterone antagonist therapy identified patients with PAH most likely to respond to initial combination therapy with ambrisentan and tadalafil. Further study to evaluate the role of aldosterone antagonist therapy in PAH is warranted.

Regimented Phosphodiesterase Type 5 Inhibitor Use Reduces Emergency Department Visits for Recurrent Ischemic Priapism.

PURPOSE: We evaluated the real-world effectiveness of regimented phosphodiesterase type 5 inhibitor dosing on recurrent ischemic priapism outcomes using emergency department visits as a proxy for therapeutic control of the disorder. MATERIALS AND METHODS: We performed a retrospective chart review of patients with recurrent ischemic priapism who were started on regimented phosphodiesterase type 5 inhibitor therapy from May 2006 to January 2020. We compared the number of emergency department visits per month during a 6-month period before treatment, during treatment and after treatment discontinuation. We extracted and categorized priapism outcomes such as priapism frequency and duration. RESULTS: Of 216 patients identified with all cause priapism 114 were diagnosed with recurrent ischemic priapism and 42 were initiated on regimented phosphodiesterase type 5 inhibitor therapy. Treatment effectiveness was analyzed for 24 evaluable patients. Priapism etiology was idiopathic in 12 patients (50%), sickle cell disease in 11 (46%) and drug-induced in 1 (4%). The median length of regimented phosphodiesterase type 5 inhibitor use was 3 months (IQR 2-7). Treatment decreased emergency department visits per month by 4.4-fold (p <0.001), priapism duration tiers (p <0.001) and priapism frequency tiers (p <0.001). Of 24 patients 22 (92%) reported improvement in priapism outcomes, 9 of whom reported resolution of recurrent ischemic priapism episodes. A subgroup analysis of 17 patients with recurrent ischemic priapism relapse after treatment discontinuation showed a significant increase in priapism duration (p <0.001) and frequency (p <0.001) but no significant change in emergency department visits per month (p=0.91). CONCLUSIONS: Regimented phosphodiesterase type 5 inhibitor therapy was an impactful treatment in managing recurrent ischemic priapism according to objective and subjective parameters. This study provides further support for the use of regimented phosphodiesterase type 5 inhibitor dosing as a preventive strategy for recurrent ischemic priapism.

Efficacy and safety of oral phosphodiesterase 5 inhibitors for erectile dysfunction: a network meta-analysis and multicriteria decision analysis.

PURPOSE: To quantitatively assess the benefit-risk ratio on the efficacy and safety of all phosphodiesterase type 5 inhibitors (PDE5i) in men with erectile dysfunction. METHODS: A systematic review with network meta-analysis, surface under the cumulative ranking analysis and stochastic multicriteria acceptability analyses were performed. Searches were conducted in Pubmed, Scopus, Web of Science without limits for time-frame or language. Randomized controlled trials evaluating the efficacy or safety of any PDE5i compared to a placebo or to other PDE5i in males with erectile disfunction were included. RESULTS: Overall, 184 articles representing 179 randomized controlled trials (50,620 patients) were included. All PDE5i were significantly more efficient than placebo. Sildenafil 25 mg was statistically superior to all interventions in enhancing IIEF (with a 98% probability of being the most effective treatment), followed by sildenafil 50 mg (80% of probability). Taladafil 10 mg and 20 mg also presented good profiles (73% and 76%, respectively). Avanafil and lodenafil were less effective interventions. Mirodenafil 150 mg was the treatment that caused more adverse events, especially flushing and headaches. Sildenafil 100 mg was more related to visual disorders, while vardenafil and udenafil were more prone to cause nasal congestion. CONCLUSION: Sildenafil at low doses and tadalafil should be the first therapeutic options. Avanafil, lodenafil and mirodenafil use are hardly justified given the lack of expressive efficacy or high rates of adverse events.

Dihydrotestosterone (DHT) rapidly increase after maximal aerobic exercise in healthy males: the lowering effect of phosphodiesterase's type 5 inhibitors on DHT response to exercise-related stress.

PURPOSE: Few data exist on dihydrotestosterone (DHT) adaptation to exercise-related stress. The aim of the study was to investigate on serum DHT and other androgens' responses to acute aerobic exercises, and to verify if a long-acting phosphodiesterase's type 5 inhibitors could influence these responses, as previously observed for salivary testosterone. METHODS: In a double-blind cross over study, 12 healthy trained male volunteers were submitted to both an acute sub-maximal and maximal exercise tests on cycle ergometer, after randomly receiving a two days placebo or tadalafil administration (20 mg, Cialis®, Ely-Lilly, Indianapolis, IN, USA). Blood sample collections were performed at different time points before and after exercise. Serum DHT, total testosterone (TT), dehydroepiandrosterone sulfate (DHEAS) and luteinizing hormone (LH), were assayed. RESULTS: Serum DHT increase in placebo treatment immediately post maximal aerobic exercise and return to basal values at 60 min of recovery whereas tadalafil administration significantly reduced the DHT increase after exercise. The values of areas under curves showed the increase of TT after acute sub-maximal and maximal exercise and of DHEAS only after acute maximal aerobic exercise independently from treatment. CONCLUSIONS: In addition to testosterone, also DHT plays an exercise-related adaptive role during high intensity aerobic exercise, but its rapid useful effects during exercise have to be determined. We hypothesized that the increased androgens secretion during exercise could be mainly related to steroidogenic enzymes modifications in peripheral tissues (i.e., muscles). Moreover, the blunting effect of tadalafil on DHT increase support a possible role of peripheral nitric oxide/GMPc related pathways in influencing physical-stress related DHT metabolism.

Whether Adding Vitamin D to Tadalafil 5 mg Treatment Is Useful in Patients with Erectile Dysfunction and Vitamin D Deficiency?

INTRODUCTION: Numerous factors such as endothelial disease and hormonal disorder cause the development of erectile dysfunction (ED). However, the relationship between vitamin D deficiency (VDD) and ED is unclear. Moreover, the benefit of vitamin D replacement on ED patients with VDD is uncertain. As far as we know, there is no study yet in the literature regarding the addition of vitamin D to phosphodiesterase type 5 inhibitors in the treatment of ED patients with VDD. In this study, we investigated whether adding vitamin D to daily tadalafil treatment would be beneficial in ED patients with VDD. METHODS: A total of 111 patients with VDD accompanying ED were retrospectively evaluated between January 2016 and December 2019. Patients were divided into 2 groups according to the treatment they received. Group 1 (n = 58) was treated with daily oral tadalafil 5 mg, while group 2 (n = 53) received oral tadalafil 5 mg and 4,000 IU vitamin D3. Total International Index of Erectile Function-15 (IIEF-15) scores and vitamin D levels of the groups were compared at the end of the study. RESULTS: The mean vitamin D level was increased statistically significant in group 2, but no difference was seen in group 1 (p < 0.001 and p > 0.05, respectively). There was a significant increase in median erectile function, orgasmic function, sexual desire, sexual satisfaction, and overall satisfaction scores in both groups (p < 0.001). However, the increase in median erectile function and sexual desire scores was significantly higher in group 2 compared to group 1 at the end of the study (p = 0.01 and p < 0.001, respectively). CONCLUSION: We found that adding vitamin D to 5 mg oral daily tadalafil treatment may have an additional positive effect on erectile function and sexual desire in ED patients with VDD.

Sensitive spectrophotometric determination of vardenafil HCl in pure and dosage forms.

OBJECTIVES: The present work aims to develop and validate a simple, rapid, cost-effective, sensitive and extractive spectrophotometric methods for the determination of phosphodiesterase type 5-inhibitor; vardenafil HCl (VARD) in pure and in dosage forms. METHODS: The developed methods are based on the formation of ion-pair complexes between vardenafil HCl and dyes, namely, bromocresol green (BCG), bromocresol purple (BCP), bromophenol blue (BPB), bromothymol blue (BTB) and eriochrom black T (EBT) in acidic buffer solutions. Different factors affecting the reactions between VARD and the dyes were studied and optimized. RESULTS: The formed complexes were extracted with methylene chloride and measured at 418, 410, 415, 417 and 520nm using BCG, BCP, BPB, BTB and EBT, respectively. The beer's law was obeyed in the ranges 1.0-10, 1.0-16, 0.5-8.0, 2.0-20 and 1.0-14µgmL-1 for BCG, BCP, BPB, BTB and EBT, respectively under the optimum conditions. The composition of the ion-pairs was found 1:1. The molar absorptivity's, Sandell's sensitivity, limits of detection and the limits of quantification were calculated. Other method validation parameters, such as accuracy, intra-day and inter-day precision, robustness, ruggedness and selectivity, have been evaluated. CONCLUSION: The proposed methods have been applied successfully for the analysis of vardenafil HCl in pure and dosage forms. The reliability of the methods was further ascertained by performing recovery studies using the standard addition method. Statistical comparison of the results with the reported method was performed by applying student's t- and F-tests and no significant statistical differences were obtained.

Treatment-related biomarkers in pulmonary hypertension patients on oral therapies.

BACKGROUND: Multiple classes of oral therapy are available for the treatment of pulmonary arterial hypertension (PAH), but there is little to guide clinicians in choosing a specific regimen or therapeutic class. We aimed to investigate whether treatment-relevant blood biomarkers can predict therapy response in prevalent PAH patients. METHODS: This prospective cohort study longitudinally assessed biomarkers along the endothelin-1 (ET-1) and nitric oxide (cGMP, ADMA, SDMA, nitrite, and S-nitrosohemoglobin) pathways along with the cGMP/NT-proBNP ratio over 12 months in patients with WHO Group 1 PAH on oral PAH-specific therapies. The relationship between biomarkers and 6MWD at the same and future visits was examined using mixed linear regression models adjusted for age. As cGMP can be elevated when NT-proBNP is elevated, we also tested the relationship between 6MWD and the cGMP/NT-pro BNP ratio. Patients with PAH with concomitant heart or lung disease or chronic thromboembolic pulmonary hypertension (CTEPH) were included in a sensitivity analysis. RESULTS: The study cohort included 58 patients with PAH treated with either an endothelin receptor antagonist (27.6%), phosphodiesterase-5 inhibitor (25.9%) or a combination of the two (43.1%). Among biomarkers along the current therapeutic pathways, ET-1 and the cGMP/NT-proBNP ratio associated with same visit 6MWD (p = 0.02 and p = 0.03 respectively), and ET-1 predicted future 6MWD (p = 0.02). ET-1 (p = 0.01) and cGMP/NT-proBNP ratio (p = 0.04) also predicted future 6MWD in the larger cohort (n = 108) of PAH patients with concomitant left heart disease (n = 17), lung disease (n = 20), or CTEPH (n = 13). Finally, in the larger cohort, SDMA associated with 6MWD at the same visit (p = 0.01) in all subgroups and ADMA associated with 6MWD in PAH patients with concomitant lung disease (p = 0.03) and PAH patients on ERA therapy (p = 0.01). CONCLUSIONS: ET-1, cGMP/NTproBNP ratio, and dimethylarginines ADMA and SDMA are mediators along pathways targeted by oral PAH therapies that associate with or predict 6MWD.

Sildenafil as a Rescue Agent Following Intestinal Ischemia and Reperfusion Injury.

BACKGROUND: Acute mesenteric ischemia carries a significant morbidity. Measures to improve blood flow parameters to the intestine may ameliorate the disease. Sildenafil, a phosphodiesterase 5 inhibitor, increases cyclic guanosine monophosphate and has been shown to prevent the effects of ischemia when given before injury. However, its effects as a rescue agent have not been established. We therefore hypothesized that sildenafil, when given as a rescue agent for intestinal ischemia, would improve mesenteric perfusion, limit intestinal epithelial injury, and decrease intestinal leukocyte chemoattractants. METHODS: Eight to 12 wk-old-male C57BL/6J mice underwent laparotomy and temporary occlusion of the superior mesenteric artery for 60 min. Following ischemia, reperfusion was permitted, and before closing the abdomen, sildenafil was injected intraperitoneally in a variety of concentrations. After 24 h, reperfusion was reassessed. Animals were euthanized and intestines evaluated for histologic injury and leukocyte chemoattractants. RESULTS: Postischemic administration of sildenafil did not improve mesenteric perfusion following intestinal ischemia and reperfusion injury. However, sildenafil did improve histologic injury scores in dose ranges of 0.01 to 10 mg/kg. No difference was noted in histological injury with 100 mg/kg dose, and all members of the 1000 mg/kg group died within 24 h of injury. Epithelial protection was not facilitated by the leukocyte chemoattractants Regulated on Activation, Normal T Cell Expressed, and Secreted, macrophage inflammatory protein 1 alpha, monocyte chemoattractant protein, neutrophil activating protein, or granulocyte colony stimulating factor. CONCLUSIONS: Administration of sildenafil following intestinal ischemia may limit intestinal mucosal injury but does not appear to alter mesenteric perfusion or leukocyte chemoattractant influx. TYPE: Basic science. LEVEL OF EVIDENCE: N/A.

Novel PDE5 inhibitors derived from rutaecarpine for the treatment of Alzheimer's disease.

A series of novel rutaecarpine derivatives were synthesized and subjected to pharmacological evaluation as PDE5 inhibitors. The structure-activity relationships were discussed and their binding conformation and simultaneous interaction mode were further clarified by the molecular docking studies. Among the 25 analogues, compound 8i exhibited most potent PDE5 inhibition with IC50 values about 0.086 µM. Moreover, it also produced good effects against scopolamine-induced cognitive impairment in vivo. These results might bring significant instruction for further development of potential PDE5 inhibitors derived from rutaecarpine as a good candidate drug for the treatment of Alzheimer's disease.

A Bayesian Network Meta-analysis of Add-on Drug Therapies Specific for Pulmonary Arterial Hypertension.

Background: Recently published meta-analyses did not discriminate between drug agents used for initial and sequential combination therapy. Objective: To assess the comparative efficacy of drugs specific for the treatment of pulmonary arterial hypertension (PAH) as add-on therapies based on 6-minute walk distance (6MWD), all-cause mortality, and discontinuation due to adverse events (AEs). Methods: EMBASE, PubMed, Cochrane Library, and ClinicalTrials.gov were searched until December 9, 2018, for the randomized, placebo-controlled clinical trials (RCTs) conducted on primarily adult patients diagnosed with PAH. Data extracted from applicable RCTs were as follows: for 6MWD mean change from baseline, the total number of patients, and the number of patients with events, per treatment. Network meta-analysis (NMA) was conducted in a Bayesian framework. Results: A total of 16 RCTs were eligible for analysis, with 4112 patients. Add-on therapy with tadalafil or inhaled treprostinil performed better than endothelin receptor antagonists alone [27 m; 95% credible interval (CrI): (11, 43); and 19 m; 95% CrI: (10, 27); respectively]. Add-on therapy with macitentan or bosentan performed better than phosphodiesterase type 5 inhibitors alone [26 m; 95% CrI: (6.4, 45); and 22 m; 95% CrI: (5.1, 38); respectively]. Differences in all-cause mortality and discontinuation due to AEs were nonsignificant. Conclusion and Relevance: Our NMA evaluated efficacy and safety of add-on therapies in patients with PAH. None of the previous meta-analyses evaluated RCTs focusing solely on patients pretreated with another PAH-specific drug therapy. Our results support guideline recommendations on combination therapy in PAH patients and add the quantitative perspective on which sequential therapy demonstrated the greatest effect size.

Effect of sildenafil on maternal hemodynamics in pregnancies complicated by severe early-onset fetal growth restriction: planned subgroup analysis from a multicenter randomized placebo-controlled double-blind trial.

OBJECTIVES: Fetal growth restriction (FGR) is associated with maternal cardiovascular changes. Sildenafil, a phosphodiesterase type-5 inhibitor, potentiates the actions of nitric oxide, and it has been suggested that it alters maternal hemodynamics, potentially improving placental perfusion. Recently, the Dutch STRIDER trial was stopped prematurely owing to excess neonatal mortality secondary to pulmonary hypertension. The main aim of this study was to investigate the effect of sildenafil on maternal hemodynamics in pregnancies with severe early-onset FGR. METHODS: This was a cardiovascular substudy within a UK multicenter, placebo-controlled trial, in which 135 women with a singleton pregnancy and severe early-onset FGR (defined as a combination of estimated fetal weight or abdominal circumference below the 10th centile and absent/reversed end-diastolic flow in the umbilical artery on Doppler velocimetry, diagnosed between 22 + 0 and 29 + 6 weeks' gestation) were assigned randomly to receive either 25 mg sildenafil three times daily or placebo until 32 + 0 weeks' gestation or delivery. Maternal blood pressure (BP), heart rate (HR), augmentation index, pulse wave velocity (PWV), cardiac output, stroke volume (SV) and total peripheral resistance were recorded before randomization, 1-2 h and 48-72 h post-randomization, and 24-48 h postnatally. For continuous data, analysis was performed using repeated measures ANOVA methods including terms for timepoint, treatment allocation and their interaction. RESULTS: Included were 134 women assigned randomly to sildenafil (n = 69) or placebo (n = 65) who had maternal BP and HR recorded at baseline. At 1-2 h post-randomization, compared with baseline values, sildenafil increased maternal HR by 4 bpm more than did placebo (mean difference, 5.00 bpm (95% CI, 1.00-12.00 bpm) vs 1.25 bpm (95% CI, -5.38 to 7.88 bpm); P = 0.004) and reduced systolic BP by 1 mmHg more (mean difference, -4.13 mmHg (95% CI, -9.94 to 1.44 mmHg) vs -2.75 mmHg (95% CI, -7.50 to 5.25 mmHg); P = 0.048). Even after adjusting for maternal mean arterial pressure, sildenafil reduced aortic PWV by 0.60 m/s more than did placebo (mean difference, -0.90 m/s (95% CI, -1.31 to -0.51 m/s) vs -0.26 m/s (95% CI, -0.75 to 0.59 m/s); P = 0.001). Sildenafil was associated with a non-significantly greater decrease in SV index after 1-2 h post-randomization than was placebo (mean difference, -5.50 mL/m2 (95% CI, -11.00 to -0.50 mL/m2 ) vs 0.00 mL/m2 (95% CI, -5.00 to 4.00 mL/m2 ); P = 0.056). CONCLUSIONS: Sildenafil in a dose of 25 mg three times daily increases HR, reduces BP and reduces arterial stiffness in pregnancies complicated by severe early-onset FGR. These changes are short term, modest and consistent with the anticipated vasodilatory effect. They have no short- or long-term clinical impact on the mother. Copyright © 2019 ISUOG. Published by John Wiley & Sons Ltd.

Pharmacokinetic modeling of intravenous sildenafil in newborns with congenital diaphragmatic hernia.

PURPOSE: We developed a pharmacokinetic model of intravenous sildenafil in newborns with congenital diaphragmatic hernia (CDH) to achieve a target plasma concentration of over 50 µg/l. METHODS: Twenty-three CDH newborns with pulmonary hypertension (64 blood samples) received intravenous sildenafil. Patients received a loading dose of 0.35 mg/kg (IQR 0.16 mg/kg) for 3 h, followed by a continuous infusion of 1.5 mg/kg/day (IQR 0.1 mg/kg/day). For model development, non-linear mixed modeling was used. Inter-individual variability (IIV) and inter-occasion variability were tested. Demographic and laboratory parameters were evaluated as covariates. Normalized prediction distribution errors (NPDE) and visual predictive check (VPC) were used for model validation. RESULTS: A two-compartment disposition model of sildenafil and a one-compartment disposition model of desmethyl sildenafil (DMS) was observed with IIV in sildenafil and DMS clearance and volume of distribution of sildenafil. NPDE and VPC revealed adequate predictability. Only postnatal age increased sildenafil clearance. This was partly compensated by a higher DMS concentration, which also has a therapeutic effect. In this small group of patients, sildenafil was tolerated well. CONCLUSIONS: This model for sildenafil in CDH patients shows that concentration-targeted sildenafil dosing of 0.4 mg/kg in 3 h, followed by 1.6 mg/kg/day continuous infusion achieves appropriate sildenafil plasma levels.

Intravenous sildenafil citrate and post-cardiac surgery acute kidney injury: a double-blind, randomised, placebo-controlled trial.

BACKGROUND: This study assessed whether i.v. sildenafil citrate prevented acute kidney injury in at-risk patients undergoing cardiac surgery with cardiopulmonary bypass. METHODS: In a double-blind RCT, adults at increased risk of acute kidney injury undergoing cardiac surgery in a single UK tertiary centre were randomised to receive sildenafil citrate 12.5 mg kg-1 i.v. over 150 min or dextrose 5% at the commencement of surgery. The primary outcome was serum creatinine measured at six post-randomisation time points. The primary analysis used a linear mixed-effects model adjusted for the stratification variables, baseline estimated glomerular filtration rate, and surgical procedure. Secondary outcomes considered clinical events and potential disease mechanisms. Effect estimates were expressed as mean differences (MDs) or odds ratios with 95% confidence intervals. RESULTS: The analysis population comprised eligible randomised patients that underwent valve surgery or combined coronary artery bypass graft and valve surgery, with cardiopulmonary bypass, between May 2015 and June 2018. There were 60 subjects in the sildenafil group and 69 in the placebo control group. The difference between groups in creatinine concentration was not statistically significant (MD: 0.88 µmol L-1 [-5.82, 7.59]). There was a statistically significant increase in multiple organ dysfunction scores in the sildenafil group (MD: 0.54 [0.02, 1.07]; P=0.044). Secondary outcomes, and biomarkers of kidney injury, endothelial function, and inflammatory cell activation, were not significantly different between the groups. CONCLUSIONS: These results do not support the use of i.v. sildenafil citrate for kidney protection in adult cardiac surgery. CLINICAL TRIAL REGISTRATION: ISRCTN18386427.