The iSEARCH randomised controlled trial protocol: a pragmatic Australian phase III clinical trial of intrapartum sildenafil citrate to improve outcomes potentially related to intrapartum hypoxia.

INTRODUCTION: We showed in a phase II randomised controlled trial (RCT) that oral sildenafil citrate in term labour halved operative birth for fetal distress. We outline the protocol for a phase III RCT (can intrapartum SildEnafil safely Avert the Risks of Contraction-induced Hypoxia? (iSEARCH)) of 3200 women in Australia to assess if sildenafil citrate reduces adverse perinatal outcomes related to intrapartum hypoxia. METHODS AND ANALYSIS: iSEARCH will enrol 3200 Australian women in term labour to determine whether up to three 50 mg oral doses of sildenafil citrate versus placebo reduce the relative risk of a primary composite end point of 10 perinatal outcomes potentially related to intrapartum hypoxia by 35% (from 7% to 4.55%). Secondary aims are to evaluate reductions in the relative risk of emergency caesarean section or instrumental vaginal birth for fetal distress by 25% (from 20% to 15%) and in healthcare costs. To detect a 35% reduction in the primary outcome for an alpha of 0.05 and power of 80% with 10% dropout in each arm requires 3200 women (1600 in each arm). This sample size will also yield >90% power to detect a 25% reduction for the secondary outcome of any operative birth (caesarean section or instrumental vaginal birth) for fetal distress. ETHICS AND DISSEMINATION: Ethical approval for the iSEARCH RCT was granted by the Hunter New England Human Research Ethics Committee (ref no: 2020/ETH02791). Results will be disseminated through websites, peer-reviewed publications, scientific meetings and social media, news outlets, television and radio. TRIAL REGISTRATION NUMBER: ACTRN12621000231842.

RidStress 2 randomised controlled trial protocol: an Australian phase III clinical trial of intrapartum sildenafil citrate or placebo to reduce emergency caesarean birth for fetal distress in women with small or suboptimally grown infants at term (≥37 weeks).

INTRODUCTION: Small for gestational age (SGA) infants are at increased risk of fetal distress in labour requiring emergency operative birth (by caesarean section (CS), vacuum or forceps). We have previously shown that maternal oral sildenafil citrate (SC) in labour halves the need for operative birth for suspected fetal distress in women with appropriately grown term infants. METHODS AND ANALYSIS: RidStress 2 is a phase III randomised, double-blinded, placebo-controlled trial of 660 women with an SGA or suboptimally grown fetus (estimated fetal weight or abdominal circumference<10th centile for gestational age) planning a vaginal birth at term. The trial will determine whether oral intrapartum SC (50 mg eight hourly) reduces the relative risk of emergency CS for fetal distress compared with placebo. The primary outcome is CS for fetal distress, and the secondary outcomes are any operative birth for fetal distress, cost-effectiveness of SC treatment and 2-year childhood neurodevelopmental outcomes. To detect a 33% reduction in the primary outcome from 30% to 20% for an alpha of 0.05 and power of 80% with 10% dropout, requires approximately 660 women (330 in each arm). This sample size will also yield >90% power to detect a similar reduction for the secondary outcome of any operative birth (CS or instrumental vaginal birth) for fetal distress. ETHICS AND DISSEMINATION: Ethics approval was granted by the Mater Misericordiae Limited Human Research Ethics Committee (EC00332) on 11 September 2020. We plan to disseminate the results of this randomised controlled trial through presentations at scientific meetings and peer-reviewed journals, adhering to all relevant reporting guidelines. TRIAL REGISTRATION NUMBER: RidStress 2 is registered with the Australian New Zealand Clinical Trials Registry (ACTRN12621000354886, 29/03/2021) and the Therapeutic Goods Association of Australia (date registered: 16 March 2021).

Sildenafil's effectiveness in the primary coronary slow flow phenomenon: a pilot randomised controlled clinical trial.

BACKGROUND: On the one hand, the primary coronary slow flow phenomenon (CSFP) can cause recurrence of chest pain, prompting medical examinations and further healthcare costs, while on the other hand, it can lead to myocardial infarction, ventricular arrhythmia and sudden cardiac death. Nevertheless, there is not any agreement on the optimal treatment for primary CSFP, so we decided to examine the effectiveness of sildenafil in this context. METHODS: This pilot study is a 12-week, triple-blind, randomised, placebo-controlled trial for receiving either 50 mg daily oral sildenafil or placebo. Twenty eligible patients aged 30-70 years from a tertiary hospital in Yazd were randomly allocated in a 1:1 ratio to two groups. The primary outcomes were the alterations in functional capacity (metabolic equivalents, METs), Duke treadmill score (DTS) and angina severity (Canadian Cardiovascular Society (CCS) class). The study protocol registration code is IRCT20220223054103N1. RESULTS: The angina severity in the Sildenafil group improved, with all receivers achieving a state of being asymptomatic during regular physical activity (CCS I). Whereas just 40% of the recipients in the placebo group achieved the same level of improvement (p=0.011). Mean METs at baseline were 9.9 (SD: 3.1) and at week 12 were 13.1 (SD: 3.3) for sildenafil and 9.56 (SD: 2.1) and 9.63 (SD: 2.4) for placebo (difference favouring sildenafil with a median increase of 3.1 (IQR: 1.1 to 4.1, p=0.008)). Median DTS scores at baseline were 3 (IQR: 0 to 9) and at week 12 were 9.5 (IQR: 7.75 to 15) for sildenafil and 7 (IQR: -1.5 to 9.25) and 8 (IQR: 1.5 to 11.25) for placebo (difference favouring sildenafil with a median increase of 5.5 (IQR: 1 to 9.2, p=0.01)). CONCLUSIONS: We suggest that a daily low dose of sildenafil could be a valuable therapeutic option for primary CSFP. TRIAL REGISTRATION NUMBER: IRCT20220223054103N1.

Improvement of Bioavailability of Sildenafil Citrate Through Taste Masked Orodispersible Film for Pulmonary Hypertension Management.

The oral bioavailability of sildenafil citrate is approximately 43%, primarily limited by the low aqueous solubility and first-pass effect. Considering the drug properties and biopharmaceutical considerations, this study aimed to develop an immediate release, taste masked orodispersible film (ODF) of sildenafil citrate for the efficient management of pulmonary arterial hypertension (PAH). The optimization was done by applying 32 full-factorial design. The drug-loaded film was prepared and evaluated for the physical and mechanical parameters like; thickness, disintegration time, tensile strength, elongation, swelling index, content uniformity, disintegration and in vitro drug release in pH 6.2 stimulated salivary fluid. The FTIR and DSC data proved excellent compatibility between the drug and polymers used. The time taken for disintegration by the optimized film was about 62.66 s, while the drug release was observed ~ 96% in 10 min. Pharmacokinetic studies exhibited better sildenafil plasma level (p < 0.05) and Cmax (p < 0.001) of orally disintegrating film which is significantly higher than the oral drug solution. The AUC0-8 (24874.425 ± 1234.45 ng. h/mL) in the oromucosal application was 1.2-fold more (p < 0.0001) than the control. The presence of sweetening and flavoring agents in the formulation masked the drug bitterness, resulting in a higher intake of the formulation in rats compared to the unmasked drug solution, as observed with in vivo taste masking studies. The importance of ODF as a feasible, effective, and optimal approach for delivering sildenafil citrate via oromucosal administration for the treatment of PAH was successfully highlighted by these results.

Comparisons and correlations of 1-month recall vs 24-hour recall in patient-reported outcomes of an exploratory, phase 2b, randomized, double-blind, placebo-controlled clinical trial of sildenafil cream, 3.6% for the treatment of female sexual arousal disorder.

BACKGROUND: Efficacy assessments in clinical trials of treatments for female sexual arousal disorder (FSAD) and other female sexual dysfunction (FSD) diagnoses rely on various patient-reported outcomes (PROs). AIMS: We sought to compare 1-month recall PRO measures among participants enrolled in a clinical trial who provided these data without (test population) vs with (control population) use of an at-home, 24-hour recall electronic diary (eDiary), capturing similar data. METHODS: Preplanned subset analysis as performed during a phase 2b, exploratory, randomized, placebo-controlled, double-blind study of sildenafil cream, 3.6% (sildenafil cream) among healthy premenopausal women with FSAD. Preliminary product efficacy was assessed via 1-month recall and 24-hour recall questionnaires. A subset of the participants, the Evaluation of Recall Subset [ERS] provided PROs via the 1-month recall instruments but did not provide data via the 24-hour recall eDiary. OUTCOMES: Responses to the 1-month recall instruments were compared among ERS (test) vs non-ERS (control) participants. Among the non-ERS population, correlations between 1-month and 24-hour recall endpoints were calculated. RESULTS: There were no significant differences in the study co-primary 1-month recall efficacy endpoints, the Arousal Sensation (AS) domain of the 28-item Sexual Function Questionnaire (SFQ28) and the Female Sexual Distress Scale - Desire, Arousal, Orgasm question 14, among ERS vs non-ERS participants during the initial 1-month no-drug run-in period or the 1-month single-blind placebo run-in period (P values > .47). Scores on these 1-month recall PROs continued to be similar after randomization for sildenafil cream (P values > .30) and placebo cream (P values > .20) assigned ERS and non-ERS participants during the 3-month double-blind dosing period. There were strong correlations between the SFQ28 AS and eDiary AS scores during the no-drug run-in (R = 0.79, P < .01) and the single-blind run-in (R = 0.73 P < .001). During the double-blind dosing period, the SFQ28 AS score continued to be highly correlated with the eDiary AS score among sildenafil cream users (R = 0.83; P < .001) and placebo cream users (R = 0.8; 2 P < .001). CLINICAL IMPLICATIONS: There was no evidence that 1-month recall PRO instruments introduce recall bias; assessing arousal sensations with 24-hour vs 1-month PRO instruments is similar and either method could be used to assess efficacy depending on study objectives. STRENGTHS AND LIMITATIONS: This preplanned subset analysis compared efficacy of PROs based on recall duration. While the subset was preplanned, the study was powered to detect significant differences in the primary efficacy objectives, not among this subset analyses. CONCLUSION: These data will be used in planning future efficacy assessments of sildenafil cream for FSAD. CLINICAL TRIAL REGISTRATION: This clinical trial was registered with ClinicalTrials.gov, NCT04948151.

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.

Safety assessment of sildenafil use in neonates: a real-world data analysis based on the FDA adverse event reporting system (FAERS).

BACKGROUND: The safety of neonatal sildenafil use remains uncertain. This study aimed to investigate adverse events (AEs) associated with sildenafil use in neonates. RESEARCH DESIGN AND METHODS: We collected data on AEs associated with sildenafil use in neonates from the US Food and Drug Administration Adverse Event Reporting System database, spanning from its inception of the database in 2004 to 2023. Disproportionality measures were employed to analyze the correlation between AEs and sildenafil. RESULTS: Sildenafil was identified as the primary suspect drug in 75 AE reports, involving 214 AEs. Three system organ classes, namely, eye disorders, hepatobiliary disorders, and vascular disorders were associated with sildenafil use. Six preferred terms, namely, flushing, retinopathy of prematurity, hyperbilirubinemia, pulmonary hemorrhage, hypotension, and diarrhea were associated with sildenafil use. Notably, hyperbilirubinemia and pulmonary hemorrhage were previously unreported AEs associated with sildenafil use. CONCLUSION: The results highlight the ongoing uncertainty surrounding the safety of neonatal sildenafil use and provide vital support for risk monitoring and identification in neonates receiving sildenafil. Additionally, the study underscores the need for continuous safety surveillance in neonates treated with sildenafil and suggests further exploration of the precise causal relationships between AEs and sildenafil.

Preliminary Efficacy of Topical Sildenafil Cream for the Treatment of Female Sexual Arousal Disorder: A Randomized Controlled Trial.

OBJECTIVE: To assess the efficacy of topical sildenafil cream, 3.6% among healthy premenopausal women with female sexual arousal disorder. METHODS: We conducted a phase 2b, exploratory, randomized, placebo-controlled, double-blind study of sildenafil cream. Coprimary efficacy endpoints were the change from baseline to week 12 in the Arousal Sensation domain of the SFQ28 (Sexual Function Questionnaire) and question 14 of the FSDS-DAO (Female Sexual Distress Scale-Desire, Arousal, Orgasm). RESULTS: Two hundred women with female sexual arousal disorder were randomized to sildenafil cream (n=101) or placebo cream (n=99). A total of 174 participants completed the study (sildenafil 90, placebo 84). Among the intention-to-treat (ITT) population, which included women with only female sexual arousal disorder and those with female sexual arousal disorder with concomitant sexual dysfunction diagnoses or genital pain, although the sildenafil cream group demonstrated greater improvement in the SFQ28 Arousal Sensation domain scores, there were no statistically significant differences between sildenafil and placebo cream users in the coprimary and secondary efficacy endpoints. An exploratory post hoc subset of the ITT population with an enrollment diagnosis of female sexual arousal disorder with or without concomitant decreased desire randomized to sildenafil cream reported significant increases in their SFQ28 Arousal Sensation domain score (least squares mean 2.03 [SE 0.62]) compared with placebo cream (least squares mean 0.08 [SE 0.71], P =.04). This subset achieved a larger mean improvement in the SFQ28 Desire and Orgasm domain scores. This subset population also had significantly reduced sexual distress and interpersonal difficulties with sildenafil cream use as measured by FSDS-DAO questions 3, 5, and 10 (all P ≤.04). CONCLUSION: Topical sildenafil cream improved outcomes among women with female sexual arousal disorder, most significantly in those who did not have concomitant orgasmic dysfunction. In particular, in an exploratory analysis of a subset of women with female sexual arousal disorder with or without concomitant decreased desire, topical sildenafil cream increased sexual arousal sensation, desire, and orgasm and reduced sexual distress. CLINICAL TRIAL REGISTRATION: ClinicalTrials.gov , NCT04948151.

Neurodevelopmental outcomes at 2 years in children who received sildenafil therapy in utero: The STRIDER randomised controlled trial.

OBJECTIVE: Severe early-onset fetal growth restriction (FGR) causes stillbirth, neonatal death and neurodevelopmental impairment. Poor maternal spiral artery remodelling maintains vasoactive responsiveness but is susceptible to treatment with sildenafil, a phosphodiesterase type 5 (PDE5) inhibitor, which may improve perinatal outcomes. DESIGN: Superiority, double-blind randomised controlled trial. SETTING: A total of 20 UK fetal medicine units. POPULATION: Pregnancies affected by FGR, defined as an abdominal circumference below the tenth centile with absent end-diastolic flow in the umbilical artery between 22+0 and 29+6 weeks of gestation. METHODS: Treatment with sildenafil (25 mg three times/day) or placebo until delivery or 32 weeks of gestation. MAIN OUTCOME MEASURES: All infants alive at hospital discharge were assessed for cardiovascular function and cognitive, speech/language and neuromotor impairment at 2 years of age. The primary outcome was survival without cerebral palsy or neurosensory impairment, or a Bayley-III composite score of >85. RESULTS: In total, 135 women were randomised between November 2014 and July 2016 (70 to sildenafil and 65 to placebo). We previously published that there was no improvement in time to delivery or perinatal outcomes with sildenafil. In all, 75 babies (55.5%) were discharged alive, with 61 infants eligible for follow-up (32 sildenafil and 29 placebo). One infant died (placebo), three mothers declined and ten mothers were uncontactable. There was no difference in neurodevelopment or blood pressure following treatment with sildenafil. Infants who received sildenafil had a larger head circumference at 2 years of age (median difference 49.2 cm, IQR 46.4-50.3, vs 47.2 cm, 95% CI 44.7-48.9 cm). CONCLUSIONS: Sildenafil therapy did not prolong pregnancy or improve perinatal outcomes and did not improve infant neurodevelopment in FGR survivors. Therefore, sildenafil should not be prescribed for this condition.

Bosentan monohydrate and sildenafil base as two companions in enabling formulations.

HYPOTHESIS: Sildenafil base and bosentan monohydrate are co-administered in a chronic therapy of pulmonary arterial hypertension (PAH). Both drugs are poorly soluble in water, and their bioavailability is limited to ca. 50 %. Since bosentan is a weak acid, whereas sildenafil is a weak base, we assumed that their co-amorphization could: (i) improve their solubility in the gastrointestinal fluids, (ii) enable to reach supersaturation and (iii) ensure stabilization of supersaturated solutions. If successful, this could accelerate the development of new fixed-dose combination drugs. EXPERIMENTS: The co-amorphous formulations were prepared using high energy ball milling. Their solid state properties were assessed using XRD, DSC, FT-MIR, and dielectric spectroscopy. Particle size distribution and surface wetting were also analyzed. Polarizing optical microscopy and scanning electron microscopy were applied to assess the microstructure of these powders. A new HPLC-DAD method was developed for a simultaneous quantification of both drugs. FINDINGS: It was shown that binary formulations in which bosentan was molecularly dispersed in sildenafil base (Tg = 64-78 °C) could be manufactured in the high energy ball milling process. When the sildenafil load was below 50 wt. %, the formulations showed the greatest thermal stability and formed long-lasting bosentan supersaturation in PBS.

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.

Off-target effect of high-dose sildenafil on adenosine 5'- diphosphate and collagen-induced platelet activation through mitogen-activated protein kinase pathway in treated BALB/C mice and in vitro experiments: A preliminary study.

ABSTRACT: Sildenafil, a common over-the-counter pill often self-administered at high doses for erectile dysfunction, has been reported to rarely cause prothrombotic events and sudden cardiac death in a few case reports. Therefore, we investigated the in vitro and in vivo effect of sildenafil treatment and dosage on platelet activation and mitogen-activated protein kinase (MAPK) phosphorylation. BALB/C mice were segregated into four groups, each having four mice each (control, low [3.25 mg/kg], medium [6.5 mg/kg], and high [13 mg/kg] sildenafil), and after the treatment, blood was drawn from each mouse and washed platelets prepared. Washed platelets were incubated with CD41 PE-Cy7 and Phospho-p38 MAPK PE antibodies and analyzed using a flow cytometer for platelet activation and adenosine 5'- diphosphate (ADP)/collagen-induced MAPK phosphorylation. Washed platelets obtained from the venous blood of 18 human volunteers, were incubated with PAC-1 FITC and Phospho-p38 MAPK PE antibodies, and platelet activation (ADP and collagen), followed by flow cytometry analysis. There was a significant increase in both platelet activation as well as MAPK phosphorylation in the presence of collagen in the high-dose (13 mg/kg) sildenafil group (P = 0.000774). Further, increased platelet activation was observed in samples that were treated with high-dose sildenafil as compared to the untreated samples (P < 0.00001). These studies show the risk of prothrombotic episodes in patients on high-dose sildenafil (100 mg), in those with even mild endothelial dysfunction due to ADP, and collagen-induced platelet activation through MAPK phosphorylation, which was not seen in the low-and intermediate-dose cohorts.

Differences in ocular adverse events associated with phosphodiesterase-5 inhibitors: a real-world pharmacovigilance study.

OBJECTIVE: Our study aims to characterize the ocular safety profiles of phosphodiesterase type 5 (PDE5) inhibitors and explore the differences among different PDE5 inhibitors. METHODS: We analyzed reports on ocular adverse events associated with sildenafil, vardenafil and tadalafil submitted to the FDA Adverse Event Reporting System (FAERS) database from the first quarter of 2004 to the first quarter of 2023. Disproportionality analysis was conducted to evaluate reporting risk profiles. RESULTS: Among 61,211 reports qualifying for analysis, 5,127 involved sildenafil, 832 vardenafil, and 3,733 tadalafil. All PDE5 inhibitors showed increased reporting odds ratios (ROR) for ocular adverse events, with vardenafil highest (ROR 4.47) followed by sildenafil and tadalafil. Key ocular adverse events included cyanopsia, optic ischemic neuropathy, visual field defects, unilateral blindness and blindness. Sildenafil showed the highest disproportionality for cyanopsia (ROR 1148.11) while vardenafil and tadalafil showed the highest disproportionality for optic ischemic neuropathy. Time-to-onset analysis also revealed significant differences, with sildenafil having a later median time-to-onset compared to vardenafil and tadalafil. CONCLUSIONS: This comprehensive pharmacovigilance study reveals distinct patterns of ocular adverse events associated with PDE5 inhibitors. These findings contribute to a better understanding of the safety profiles of PDE5 inhibitors and may guide healthcare professionals in clinical decision-making.

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.

Effect of topical sildenafil on wound healing and oxidative stress in rats.

BACKGROUND: In this study, the effects of topical sildenafil applications on oxidative damage levels and antioxidative metabolism and their contribution to wound healing and treatment were investigated. MATERIALS AND METHODS: A total of 24 healthy male rats aged 16-18 weeks, each weighing 200-250 g, were randomly divided into three groups: Group A received a saline solution, Group B received an epithelializing cream, and Group C received sildenafil cream. Following skin preparation and anesthesia, 6 mm diameter punch biopsies created wounds on the rats' backs. The treatment protocol involved daily topical dressing for seven days, after which tissue and blood samples were collected for analysis. Tissue samples underwent histopathological examination, while malondialdehyde (MDA) levels, superoxide dismutase (SOD), glutathione peroxidase (GPx), and catalase activities in wound tissue and blood samples were measured. RESULTS: The wound surface area created by the punch decreased in all groups by the end of the seventh day; However, the degree of wound healing differed in favor of the sildenafil cream group. Histopathologically, according to Greenhalgh's Modified Wound Healing Scoring System, all findings were graded. In the Anova test, the differences between glutathione peroxidase, catalase, and malondialdehyde levels in the serum and tissue of rats was statistically significant (P < 0.05), whereas superoxide dismutase levels were not statistically significant (P > 0.05). In the Bonferroni test, the serum CAT levels between groups A and C (P = 0.003), between groups B and C (P = 0.035), and the serum MDA levels between groups A and B (P = 0.018) and between groups A and C (P = 0.001) were found to be significant statistically. By the way, the results between tissue CAT levels in the B and C groups (P = 0.020) and between tissue GPx levels (P = 0.001) in all groups were also significant statistically. CONCLUSIONS: The study findings indicated that topical application of sildenafil led to noteworthy alterations in serum and tissue antioxidative metabolism as well as oxidative damage levels among rats with induced wounds. Sildenafil may be useful in wound treatment; it has been concluded that it is capable of directing new studies to be carried out.

Perioperative sildenafil therapy in pulmonary hypertension associated with congenital cardiac disease: An updated meta-analysis.

To provide an updated meta-analysis to evaluate the efficacy and safety of sildenafil on pediatric patients with pulmonary hypertension (PH) associated with congenital heart disease (CHD). To assess the efficacy and safety of sildenafil, five outcomes, time duration of post-operative need for mechanical ventilation, time duration of post-operative ICU stay, length of hospitalization (LOH), the incidence of mortalities and pulmonary arterial pressure to aortic pressure ratio (PAP/AoP) were regarded as primary efficacy outcomes. Standardized mean difference (SMD) was calculated for continuous data. In comparison to the control group (CG), there was a significant decrease in the time duration of ICU stay in the sildenafil group (SG) (SMD = -0.61 [95% CI -1.17, 0.04]; P < 0.01, I2 = 85%). Length of hospitalization was assessed in the sildenafil and control groups (SMD = -0.18 [95% CI -0.67, 0.31] P = 0.05, I2 = 62%). However, there was no significant difference seen in mortality rates between the SG and CG (SMD = 0.53 [ 95% CI 0.13, 2.17] p = 0.61, I2 = 0%), in the time duration of postoperative mechanical ventilation between the SG and CG (SMD = -0.23 [95% CI -0.49, 0.03] p = 0.29, I2 = 19%), or PAP/AoP ratio between the SG and CG (SMD = -0.42 [95% CI -1.35, 0.51] P < 0.01, I2 = 90%). Based on our analysis, sildenafil has little to no effect in reducing postoperative morbidity and mortality due to PH in infants and children with CHD.

Intra-Amniotic Sildenafil and Rosiglitazone Late in Gestation Ameliorate the Pulmonary Hypertension Phenotype in Congenital Diaphragmatic Hernia.

BACKGROUND: Pulmonary hypertension remains difficult to manage in congenital diaphragmatic hernia (CDH). Prenatal therapy may ameliorate postnatal pulmonary hypertension. We hypothesized that intra-amniotic (IA) injection of either sildenafil, a phosphodiesterase 5 inhibitor, or rosiglitazone, a PPAR-γ agonist, or both late in gestation would decrease the detrimental pulmonary vascular remodeling seen in CDH and improve peripheral pulmonary blood flow. METHODS: Pregnant rats were gavaged with nitrogen on embryonic day (E) 9.5 to induce fetal CDH. Sildenafil and/or rosiglitazone were administered to each fetus via an intra-amniotic injection after laparotomy on the pregnant dam at E19.5, and fetuses delivered at E21.5. Efficacy measures were gross necropsy, histology, peripheral blood flow assessment using intra-cardiac injection of a vascular tracer after delivery, and protein expression analysis. RESULTS: Intra-amniotic injections did not affect fetal survival, the incidence of CDH, or lung weight-to-body weight ratio in CDH fetuses. IA sildenafil injection decreased pulmonary vascular muscularization, and rosiglitazone produced an increase in peripheral pulmonary blood flow distribution. The combination of sildenafil and rosiglitazone decreased pulmonary artery smooth muscle cell proliferation. These intra-amniotic treatments did not show any negative effects in either CDH fetuses or control fetuses. CONCLUSION: IA injection of sildenafil and rosiglitazone late in gestation ameliorates the pulmonary hypertensive phenotype of CDH and may have utility in clinical translation. LEVEL OF EVIDENCE: Not applicable.

Efficient administration of a combination of nifedipine and sildenafil citrate versus only nifedipine on clinical outcomes in women with threatened preterm labor: a systematic review and meta-analysis.

BACKGROUND: Preterm labor (PTL) is a common and serious pregnancy disorder that can cause long-term neurological issues in the infant. There are conflicting studies concerning whether sildenafil citrate (SC) reduces preterm labor complications. Therefore, the meta-analysis aimed to examine the clinical outcomes in women with threatened PTL who received nifedipine plus SC therapy versus only nifedipine. METHODS: For the original articles, six databases were searched using relevant keywords without restriction on time or language until January 13, 2024. The Cochrane risk-of-bias tool for randomized trials (RoB) and the Risk of Bias Assessment Tool for Nonrandomized Studies (RoBANS) were both used to assess the risk of bias in randomized and non-randomized studies, and GRADE determined the quality of our evidence. Meta-analysis of all data was carried out using Review Manager (RevMan) version 5.1. RESULTS: Seven studies with mixed quality were included in the meta-analysis. The study found that combining nifedipine and SC resulted in more prolongation of pregnancy (MD = 6.99, 95% CI: 5.32, 8.65, p < 0.00001), a lower rate of delivery in the 1st to 3rd days after hospitalization (RR = 0.62, 95% CI: 0.50, 0.76, p < 0.00001), a higher birth weight (252.48 g vs. nifedipine alone, p = 0.02), and the risk ratio of admission to the neonatal intensive care unit (NICU) was significantly lower (RR = 0.62, 95% CI: 0.50, 0.76, p < 0.00001) compared to nifidepine alone. The evidence was high for prolongation of pregnancy, delivery rate 24-72 h after admission, and NICU admission, but low for newborn birth weight. CONCLUSIONS: Given the effectiveness of SC plus nifedipine in increased prolongation of pregnancy and birth weight, lower delivery in the 1st to 3rd days after hospitalization, and NICU admission, Gynecologists and obstetricians are suggested to consider this strategy for PTL management, although additional article rigor is required to improve the quality of the evidence.