Sildenafil Vs. Tadalafil for The Treatment of Benign Prostatic Hyperplasia: A Single-arm Self-controlled Clinical Trial.

PURPOSE: To compare the efficacy and adverse events of sildenafil monotherapy for benign prostatic hyperplasia (BPH) with its FDA-approved counterpart, tadalafil. MATERIALS AND METHODS: In this single-arm self-controlled clinical trial, 33 patients were enrolled. All patients underwent a 6-week treatment with sildenafil, followed by a 4-week washout period and finally a 6-week treatment with tadalafil. Patients were examined on each appointment and post-void residual (PVR) urine, International Prostate Symptom Score (IPSS) and Quality of life index (IPSS-QoL index) were recorded subsequently. Efficacy of each drug regimen was then evaluated by comparing these outcome parameters. RESULTS: Both sildenafil and tadalafil were shown to improve PVR (both p < .001), IPSS (both p < .001) and IPSS- QoL index (both p < .001) significantly. Sildenafil was more effective than tadalafil in reducing PVR (mean difference (95%CI) = 9.91% (4.11, 15.72), p < .001) and ameliorating IPSS-QoL index (mean difference (95%CI) = 19.3% (4.47, 34.41), p = .027). Moreover, although not significant, sildenafil reduced IPSS more than tadalafil (mean difference (95%CI) = 3.33% (-0.22, 6.87), p = .065). Concurrent erectile dysfunction did not affect responsiveness to therapy with either sildenafil or tadalafil but age was inversely related to post-treatment IPSS in both sildenafil (B = 0.21 (0.04, 0.37), p = .015) and tadalafil (B = 0.14 (0.02, 0.26), p = .021) regimens with a more prominent role in responsiveness to sildenafil (ß = 0.31) compared to tadalafil (ß = 0.19). CONCLUSION: Considering the significantly better improvement of PVR and IPSS-Qol index with sildenafil, this drug can be nominated as a suitable alternative for tadalafil as a BPH treatment, especially in younger patients who don't have any contraindications.

Combined Intravenous Sildenafil and L-Arginine Administration in a Porcine Animal Model: Hemodynamic Safety Profile and Effects on Coronary Blood Flow.

BACKGROUND: Endothelial dysfunction in the nitric oxide-cyclic guanosine monophosphate pathway is a potential contributor to perioperative myocardial ischemia. The nitric oxide precursor, L-arginine, and the cyclic guanosine monophosphate degradation blocker, sildenafil, have vasodilatory effects under high dosage. OBJECTIVE: This study examined the hemodynamic safety and effect profiles of the combined administration of L-arginine and sildenafil using an in-vivo pig model. METHODS: Hemodynamic safety including mean arterial pressure, central venous pressure, heart rate, coronary vascular resistance, and systemic vascular resistance, as well as effect profiles including cardiac output and left anterior descending blood flow were measured in ten female swine after administrations of L-arginine, sildenafil, as well as combined L-arginine and sildenafil. Measurements were compared using repeated-measures analysis of variance and linear mixed models. RESULTS: The combination of L-arginine and sildenafil produced a significant dose-dependent increase in left anterior descending flow and cardiac output. In contrast, mean arterial pressure, heart rate, central venous pressure, coronary vascular resistance, and systemic vascular resistance did not show any significant changes. No significant change in serum osmolality was observed after administrations of L-arginine. CONCLUSIONS: The combined intravenous administration of sildenafil and L-arginine in a porcine animal model was safe, well tolerated, and had at least additive effects on left anterior descending artery blood flow. Simultaneous application of both drugs might have dose-sparing effects leading to desired coronary effects at lower and safer sildenafil and L-arginine plasma concentrations. Hyperosmolality was only a minor factor in L-arginine hemodynamic effects.

Addition of sildenafil citrate for treatment of severe intrauterine growth restriction: a double blind randomized placebo controlled trial.

Background: Severe intrauterine growth restriction complicates approximately 0.4% of the pregnancies. It increases the risk of perinatal morbidity and mortality.Subjects and methods: A double blind placebo controlled trial was conducted in Beni Suef University hospitals during 2017. It included 46 pregnant women with severe intrauterine growth restriction. Women were randomly allocated into two groups each included 23 patients. Intervention group received sildenafil citrate 20 mg orally three times a day, in addition to fish oil and zinc supplementation. Control group received tablets similar to sildenafil and the same treatment as intervention group. Primary outcomes included improvement in umbilical and middle cerebral arteries pulsatility indices and abdominal circumference.Results: Umbilical and middle cerebral arteries Doppler indices showed significant difference between groups after intake of sildenafil. Umbilical artery pulsatility index decreased significantly (p value = .001) while middle cerebral artery pulsatility index increased significantly in intervention group (p value0.001). Moreover, abdominal circumference growth velocity improved after two weeks of sildenafil intake (p value = .001).Conclusions: Sildenafil citrate may improve uteroplacental and fetal cerebral perfusion in pregnancies complicated by severe intrauterine growth restriction. It also improves abdominal circumference growth velocity. A wide scale randomized trials are needed for evaluation of neonatal and long term morbidity and mortality outcomes of pregnancies treated by sildenafil citrate.

A Case of Hepatotoxicity Induced by Adulterated "Tiger King", a Chinese Herbal Medicine Containing Sildenafil.

Detection of Phosphodiesterase Type 5 (PDE-5) inhibitors and their analogues in "100% natural" or "herbal" supplements have been described in numerous reports. However, few reports have been published in relation to actual harm caused by counterfeit erectile dysfunction herbal supplements. We describe a case of a 65-year old male admitted to a tertiary hospital with acute liver toxicity, possibly induced by adulterated "Chinese herbal" supplement "Tiger King" for sexual enhancement. Chemical analysis of the tablets discovered the presence of therapeutic doses of sildenafil with no other herbal components. Other medications were excluded as potential causes of the hepatic impairment. According to the Naranjo adverse drug reaction scale and the Roussel Uclaf Causality Assessment Method (RUCAM) the probability of association of Hepatotoxicity with Sildenafil was "possible" and "probable" respectively (Naranjo score of 4, RUCAM score of 7). Within three days of admission, the patient's clinical status and liver function improved without any specific treatment. His liver function tests normalized 30 days post discharge. Further pharmacovigilance actions should be taken by regulatory authorities and pharmaceutical companies in order to determine the relation between sildenafil and hepatotoxicity. This case emphasizes the importance of raising public awareness on the potential dangers of "Tiger king" in particular, and other counterfeit medications or herbal supplements of unknown origin.

PDE-5 inhibitors: clinical points.

Erectile dysfunction is usually of vascular origin and is frequently encountered in men with cardiovascular disease. The introduction of phosphodiesterase-5 inhibitors has revolutionized the management of patients with erectile dysfunction. Currently available phosphodiesterase-5 inhibitors have distinct pharmacokinetic and pharmacodynamic properties, thus permitting for tailoring sexual therapy according to patient characteristics and needs. Phosphodiesterase-5 inhibitors possess vasorelaxing properties and exert systemic hemodynamic effects, which need to be taken into account when other cardiovascular drugs are co-administered. Special caution is needed with alpha-blockers, while the co-administration with nitrates is contra-indicated due to the risk of life-threatening hypotension. This review presents the advent of sexual therapy, describes the mechanism of action and the specific characteristics of commercially available phosphodiesterase-5 inhibitors, summarizes the efficacy and safety of these drugs with special emphasis on the cardiovascular system, and discusses the clinical criteria used for the selection of each drug for the individual patient.