Acute electroretinographic changes during Sildenafil Citrate (Viagra) treatment for Erectile Dysfunction.

The authors describe their findings on 12 subjects who were treated with 50 mg of Sildenafil Citrate (Viagra) and underwent ERG measurements prior to and 1 hour after ingestion. The Naka-Rushton equation was used to describe the b-wave luminance-response function of the scotopic ERG. Statistically significant differences were noted in the Vmax and K values.Sildenafil Citrate (Viagra) ingestion resulted in an increase in Vmax (higher rod response to light stimuli) and a decrease in K (higher sensitivity)

Sildenafil for selective serotonin reuptake inhibitor-induced Erectile Dysfunction in elderly male depressed patients.

Treatment with antidepressants, especially agents with potent serotonergic effects, is frequently associated with sexual side effects. In the present study, we examined the efficacy of sildenafil, a potent phosphodiesterase inhibitor, in the treatment of elderly men (n = 10; 70-81 years) with Erectile Dysfunction induced by antidepressant treatment for major depressive disorder. Eligible subjects were instructed to addSildenafil Citrate (Viagra) (25-50 mg/day) to their current drug treatment. Clinical assessment of erectile function was performed at beginning of treatment withSildenafil Citrate (Viagra) and at follow up, 4 weeks later. All patients reported an improvement of their erectile capacity, and in 7 out of 10 subjects, erectile function returned to a normal level.Sildenafil Citrate (Viagra) appears to be a safe and well-tolerated agent in elderly subjects. We noted side effects in 2 patients (flashes), but the side-effects were bothersome only to one patient (headache). It appears thatSildenafil Citrate (Viagra) coadministration improves Erectile Dysfunction associated with selective serotonin reuptake inhibitor ongoing treatment in elderly patients

Stimulation of the nitric oxide-guanosine 3', 5'-cyclic monophosphate pathway by sildenafil: effect on rectal muscle tone, distensibility, and perception in health and in irritable bowel syndrome.

OBJECTIVES: Nitric oxide, a neurotransmitter in the noncholinergic, nonadrenergic nervous system, is a mediator of relaxation of GI smooth muscle and of visceral nociception mainly studied in vitro.Sildenafil Citrate (Viagra) stimulates the nitric oxide guanosine 3', 5'-cyclic monophosphate (NO-cGMP) pathway through inhibition of phosphodiesterase 5. The aims of this study were to evaluate in vivo the effect of stimulation of the NO-cGMP pathway on rectal tone, distensibility, and perception in healthy individuals and in patients with irritable bowel syndrome (IBS). METHODS: In eight healthy subjects and four patients with IBS rectal tone, distensibility and perception thresholds were measured with an electronic barostat both before and 60 min after administration ofSildenafil Citrate (Viagra) (50 mg p.o.). Perception was scored on a graded scale of 0-6. At the end of a distension series an anatomic questionnaire was filled out by the subjects. RESULTS:Sildenafil Citrate (Viagra) significantly reduced rectal tone in healthy subjects (intrabag volume predrug: 145.5 +/- 18.7 ml vs postdrug: 164.4 +/- 16.9 ml, p = 0.01) and IBS (111.3 +/- 25.2 ml vs 136.5 +/- 33.3 ml; p = 0.01) but did not alter rectal compliance (healthy subjects: 5.8 +/- 0.4 vs 6.3 +/- 0.6 ml/mm Hg, p > 0.05; IBS subjects: 6.1 +/- 0.6 vs 7.1 +/- 1.0 ml/mm Hg, p > 0.05). Intrabag pressure and rectal wall tension to reach perception thresholds for initial sensation, sensation of stool, and urgency were not altered by sildenafil. However, intrabag volumes to reach these thresholds were significantly increased bySildenafil Citrate (Viagra) both in healthy subjects and in patients with IBS. Viscerosomatic referral was unchanged. CONCLUSIONS: Stimulation of the NO-cGMP pathway decreases rectal tone but does not influence rectal distensibility. Relaxation of the rectum is accompanied by an increase in rectal volumes to reach perception thresholds in healthy subjects and in patients with IBS, but no direct effect on rectal perception can be demonstrated

Erectile function after brachytherapy with external beam radiation for prostate cancer.

The effect of therapeutic modalities on sexual potency is an important consideration for patients choosing a treatment for prostate cancer. We assessed erectile function after iridium-192 (1r-192) high-dose rate (HDR) brachytherapy with external beam radiation therapy (EBRT), and examined the efficacy ofSildenafil Citrate (Viagra) after this treatment. Forty-two prostate cancer patients (T1c to T3bN0M0) were treated with 22Gy HDR brachytherapy with 36.8Gy EBRT without neoadjuvant hormone therapy. Erectile function was assessed using a 5-item version of the International Index of Erectile Function questionnaire (IIEF-5), pre, 3 and 12 months after treatment, Potency was defined as an IIEF-5 score > or = 11. Ten patients with potency before HDR brachytherapy with EBRT with or without neoadjuvant hormone therapy requestedSildenafil Citrate (Viagra) 3 months after treatment. The mean IIEF-5 score of all patients was 10.5 +/- 8.5, 4.5 +/- 5.3 (p < 0.001), and 3.8 +/- 4.7 (p < 0.001), pre, 3 and 12 months after treatment, respectively. Seventeen (40.4%) patients were potent before treatment. The mean IIEF-5 score of those patients was 15.8 +/- 3.2, 9.6 +/- 5.1 (p = 0.04), and 11.3 +/- 6.1 (p = 0.06), pre, 3 and 12 months after treatment, respectively. Ten of 17 (58.8%) patients maintained their potency 12 months after treatment. In 10 patients with potency before treatment who were treated with sildenafil, the mean IIEF-5 score increased from 6.2 +/- 3.5 at 3 months to 13.6 +/- 5.1 (p < 0.001) at 12 months after treatment. Eight of 10 (80%) patients treated withSildenafil Citrate (Viagra) had recovered 12 months after treatment. HDR brachytherapy with EBRT can be performed with favorable results for maintaining potency

Identification system forSildenafil Citrate (Viagra) in health foods

A substantially available identification system forSildenafil Citrate (Viagra) in health foods was established using 3 different analytical methods; i.e. TLC, preparative TLC/MS and HPLC/photo-diode array.Sildenafil Citrate (Viagra) in health foods was extracted with ethyl acetate under alkaline conditions as sample solutions for TLC and preparative TLC, and also extracted with 50% methanol and then diluted with solution of HPLC mobile phase for HPLC. The sample solution for TLC was applied to Silica gel 60 F254 plates with chloroform/methanol/28% ammonia (90:1:5, under layer) as mobile phase. Spots were located under UV radiation at 254 nm and 366 nm, and spraying dragendorff reagent. The conditions for preparative TLC were the same as these of TLC method, and samples abtained from preparative TLC were determined by MS with APCI interface, under both positive and negative modes. The HPLC analysis was carried out on a column of Cosmosil 5C18-AR (4.6 mm x 150 mm, 5 microns) with 0.05 mol/l phosphate buffer pH 3.0/acetonitrile(73:27) as mobile phase and the eluate was monitored by a photo-diode array detector. The quantitative analysis was available, when the peak of this sample on HPLC was detected at 290 nm. When this system was applied to commercial health foods,Sildenafil Citrate (Viagra) was identified and their contents were 25 mg-45 mg/tablet or bottle. These contents nearly correspond to that in Viagra, 25 mg, 50 mg/tablet. Therefore, there is a fear of side effects for Sildenafil, when it is taken as health foods

Systemic and splanchnic haemodynamic effects ofSildenafil Citrate (Viagra) in an in vivo animal model of cirrhosis support for a risk in cirrhotic patients.

OBJECTIVES:Sildenafil Citrate (Viagra) is a selective inhibitor of the cGMP-specific phosphodiesterase type V (PDE-V) in the corpus cavernosum. PDE-V is also present in the mesenteric artery. Cirrhosis is complicated by a splanchnic vasodilation attributed to a local overproduction of nitric oxide (NO). AsSildenafil Citrate (Viagra) potentiates the effects of NO, it may further decrease mesenteric vascular tone and increase portal venous blood flow. The aim is to evaluate the effects ofSildenafil Citrate (Viagra) on the systemic and splanchnic haemodynamics in an experimental model of cirrhosis. METHODS: Secondary biliary cirrhosis was induced in male Wistar rats by common bile duct ligation (CBDL, n=8); control rats were sham-operated (sham, n=7). The mean arterial pressure (MAP), portal venous pressure (PVP) and arterial mesenteric blood flow (MBF) were measured after intramesenteric (0.01-10 mg/kg) and after intravenous (i.v.) (0.01-10 mg/kg) administration of sildenafil. RESULTS: Baseline PVP was significantly higher in CBDL than in sham rats, whereas baseline MAP tended to be lower and MBF tended to be higher in CBDL compared with sham rats. Both intramesenteric and i.v. injection ofSildenafil Citrate (Viagra) significantly decreased MAP and increased MBF and PVP in a dose-dependent way. The decrease in MAP was significantly less important in CBDL than in sham rats. The increase in MBF was importantly lower in CBDL than in sham rats. PVP tended to increase more significantly in sham rats than in CBDL. CONCLUSION:Sildenafil Citrate (Viagra) increases MBF and PVP and induces systemic hypotension. The effects are less pronounced in cirrhosis, suggesting vascular hyporesponsiveness to sildenafil. Although the rise in PVP in cirrhotic animals is smaller than in controls, it may present a risk for haemorrhagic complications. Further studies are necessary before prescribingSildenafil Citrate (Viagra) to patients with cirrhosis

Sildenafil Citrate (Viagra) augments sodium nitroprusside-induced but not nitroglycerin-induced hypotension in dogs.

We investigated whether Sildenafil Citrate (Viagra) may reduce the dose of nitrovasodilators to induce deliberate hypotension. Ten mongrel dogs were acutely instrumented with a femoral artery catheter and a pulmonary artery catheter. Sodium nitroprusside (SNP; 1-16 microg. kg(-1). min(-1)) or nitroglycerin (NTG; 2-32 microg. kg(-1). min(-1)) was IV given to induce hypotension. The study consisted of two occasions, in a random order, in each animal: one withSildenafil Citrate (Viagra) pretreatment (1 mg/kg IV followed by 0.3 mg. kg(-1). h(-1)) and the other without to serve as a control. Hemodynamic variables were continuously monitored. Plasma cyclic guanosine monophosphate (cGMP) concentrations were measured by radioimmunoassay. Both SNP and NTG produced dose-dependent decreases in mean arterial blood pressure without affecting the heart rate in the presence as well as in the absence of sildenafil. Systemic vascular resistance index and mean pulmonary arterial pressure were also decreased. The magnitude of mean arterial blood pressure and systemic vascular resistance index reductions caused by SNP was augmented by sildenafil, whereas that caused by NTG was not affected. Neither SNP nor NTG alone altered the plasma cGMP concentrations.Sildenafil Citrate (Viagra) increased the plasma cGMP concentration, which was further increased by SNP but not affected by NTG. These results indicate thatSildenafil Citrate (Viagra) may reduce the dose of SNP in producing deliberate hypotension in the dog. The potentiation of SNP-induced hypotension bySildenafil Citrate (Viagra) may be related to an augmented accumulation of cGMP. IMPLICATIONS:Sildenafil Citrate (Viagra) may reduce the dose of sodium nitroprusside required to induce deliberate hypotension and hence the potential for cyanide toxicity

Sildenafil improves cutaneous microcirculation in patients with coronary artery disease: a monocentric, prospective, double-blind, placebo-controlled, randomized cross-over study.

Endothelial dysfunction of precapillary arterioles impairs nutritional microcirculation at rest as well as during post-ischemic reactive hyperemia. In this monocentric, prospective, double-blind, placebo-controlled, randomized cross-over study we investigated the acute effect of 50 mg sildenafil, a selective PDE-5 inhibitor, on resting and post-ischemic capillary circulation in twenty patients with angiographically confirmed coronary artery disease not taking nitrates or NO-donors. Mean erythrocyte velocity in digital nail-fold capillaries was determined before and afterSildenafil Citrate (Viagra) and placebo, both baseline and after a three-minutes supra-systolic occlusion of the upper arm. Primary efficacy parameter was the drug effect on peak velocity during reactive hyperemia (peak velocity: V(max)). Post ischemic maximal capillary erythrocyte velocity V(max) significantly increased by 47% one hour after 50 mgSildenafil Citrate (Viagra) (mean value+/-standard deviation: 0.85+/-0.42 mm/s vs. 0.58+/-0.18 mm/s at baseline, p=0.0023), whereas placebo had no effect (p=0.5248). The difference betweenSildenafil Citrate (Viagra) and placebo was significant (p=0.0129) and sildenafil's effect can be regarded as biometrically highly relevant with standardized difference according to Cohen of 0.81. In spite a small decrease of both systolic and diastolic blood pressure after sildenafil,Sildenafil Citrate (Viagra) significantly increased capillary erythrocyte velocity at rest. CONCLUSION: A single oral dose ofSildenafil Citrate (Viagra) significantly increased resting and post-ischemic cutaneous capillary circulation in patients with coronary artery disease. Future studies should assess whetherSildenafil Citrate (Viagra) also improves nutritional capillary blood flow in other organs and in other diseases with impaired endothelial function and microcirculation, for example in diabetic microangiopathy