Efficacy and safety ofSildenafil Citrate (Viagra) for treating Erectile Dysfunction in patients on dialysis.

OBJECTIVE: To assess the efficacy ofSildenafil Citrate (Viagra) for Erectile Dysfunction (ED) in patients on haemodialysis (HD) or peritoneal dialysis (PD), as men with end-stage renal disease (ESRD) often have sexual dysfunction (up to 82% among those on chronic dialysis). PATIENTS AND METHODS: Forty-one patients with ED and in ESRD participated in an open-label prospective study. Thirty patients on HD and 11 on PD were asked to complete the International Index of Erectile Function (IIEF) and Fugl-Meyer life-satisfaction scale before and afterSildenafil Citrate (Viagra) treatment. A total score in the erectile function domain of < or = 25 was accepted as indicating ED. All patients were started on a 25-mg dose, which was increased to 50 mg if there was no response after two trials. In addition, the overall efficacy question was used to evaluate satisfaction, and patients reported any side-effects during treatment. RESULTS: The erectile function and intercourse satisfaction domains improved significantly in both groups (P < 0.01). AfterSildenafil Citrate (Viagra) treatment, two-thirds of those on HD (20/30) and nine of the 11 on PD recovered their erectile function. The pretreatment scores on the IIEF and four domains (except sexual desire) of those responding were significantly higher than in those not responding (P < 0.05). The satisfaction rate on the overall efficacy question was 80% and 82% for the HD and PD groups, respectively. At least one side-effect was seen in 17 patients (43%); one had severe hypotension in the PD group. Overall, mild headache (seven patients, 18%) and flushing (12, 30%) were reported most often. CONCLUSIONS:Sildenafil Citrate (Viagra) is a safe and satisfactory drug for improving erectile function in patients with ESRD. Patients were satisfied whether treated by HD or PD. Pretreatment scores on the IIEF may be useful for predicting the success of treatment

Potential for use of pulse wave analysis in determining the interaction betweenSildenafil Citrate (Viagra) and glyceryl trinitrate.

BACKGROUND: The early part of the central aortic pressure pulse, with amplitude (PI - Pd), is generated by left ventricular ejection, while the latter part (or augmented pressure), with amplitude (Ps - Pi), is generated by the reflected wave arriving during systole. The effects of arterial vasodilator agents, especially nitrates, on central aortic systolic blood pressure are grossly underestimated by sphygmomanometric measurements of brachial artery pressure. HYPOTHESIS: The objective of this study was to investigate the potential for use of central arterial pulse wave analysis, obtained noninvasively from the radial pulse, in determining the interaction betweenSildenafil Citrate (Viagra) and the nitric oxide donor drug glyceryl trinitrate (GTN). METHODS: Central aortic pressure waveforms were generated from noninvasively measured radial artery pressure wave-forms and subjected to pulse wave analysis to determine the interaction betweenSildenafil Citrate (Viagra) and transdermally applied GTN. RESULTS: Transdermal GTN (2.5, 5.0, and 15 mg per 24-h patches) alone caused no consistent change in sphygmomanometer-determined systolic or diastolic pressures, but there was a consistent, dose-related fall in amplitude of the augmented systolic pressure, (Ps - Pi), of 4.0, 7.0, and 11 mmHg, respectively, with little change in diastolic pressure. The 2.5 mg patch caused a fall of 4.0 mmHg in aortic systolic pressure, while augmentation index (AIx) fell from 20 to 11% and pulse pressure fell 18%. When oralSildenafil Citrate (Viagra) (50 mg) was administered after GTN (2.5 mg), aortic systolic pressure fell another 4.0 mmHg. This decrease in systolic pressure caused a fall in AIx to almost 0.0%; pulse pressure fell another 9.0%. CONCLUSION: These modifications in aortic systolic and pulse pressure are due primarily to reduction in wave-reflection amplitude and are not detected by sphygmomanometer-measured brachial artery pressure

Are adverse effects ofSildenafil Citrate (Viagra) also caused by inhibition of diamine oxidase?

BACKGROUND: Sildenafil Citrate (Viagra) (Viagra), a drug used to treat Erectile Dysfunctions, causes adverse reactions such as headache, flushing or nasal congestion. Sildanefil's potency as inhibitor of diamine oxidase was investigated, as side effects may also be induced by histamine itself due to an impaired histamine metabolism. METHODS: Placental diamine oxidase inhibition experiments were performed with consecutive dilutions of Sildenafil Citrate (Viagra) (10(-5) to 10(-9) mol/l). In 9 male volunteers in vivo diamine oxidase inhibition was investigated after taking 100 mg Sildenafil Citrate (Viagra). RESULTS: Sildenafil Citrate (Viagra) did not inhibit placental diamine oxidase either in vitro or in vivo. However, infusion of 300 mg of cimetidine inhibited diamine oxidase activity by 27 +/- 7% 15 min after infusion, demonstrating that drugs may inhibit diamine oxidase in vivo. CONCLUSION: As side effects ofSildenafil Citrate (Viagra) are not caused due to inhibition of diamine oxidase, Sildenafil Citrate (Viagra) seems to be harmless for patients suffering from histamine intolerance.

IsSildenafil Citrate (Viagra) failure in men after radical retropubic prostatectomy (RRP) due to arterial disease? Penile duplex Doppler findings in 174 men after RRP.

Sildenafil is frequently the first-line treatment for post-radical retropubic prostatectomy (RRP) Erectile Dysfunction (ED) with maximum treatment satisfaction rates of 43%-80%. The etiology of Erectile Dysfunction after RRP has been attributed to psychogenic, vascular, veno- occlusive or nerve injury causes. The purpose of this study was to gain insight into the penile duplex Doppler arterial parameters in men with ED after RRP who failed sildenafil. The purpose was to assess whetherSildenafil Citrate (Viagra) failure after RRP is associated with underlying corporal arterial disease. A total of 174 consecutive men presenting withSildenafil Citrate (Viagra) refractory ED after nerve-sparing RRP underwent color duplex penile Doppler evaluation with vasoactive injection. Mean age was 59.6 y and mean time from surgery was 11.6 months. Some 81% (141/174) of the men had no pre-operative ED (PED). Significant differences in penile duplex Doppler parameters for arterial disease were seen between men with and without PED. In men without PED, 19% (27/141) manifested arterial insufficiency. However, in men with PED, 50% (16/33) demonstrated arterial disease. Nerve sparing status did not affect the presence of arterial disease.Sildenafil Citrate (Viagra) refractory Erectile Dysfunction after RRP in men without PED is not predominantly associated with penile Doppler parameters consistent with arterial insufficiency

Synergistic effects of ANP andSildenafil Citrate (Viagra) on cGMP levels and amelioration of acute hypoxic pulmonary hypertension.

We hypothesized that the phosphodiesterase 5 inhibitor, sildenafil, and the guanosine cyclase stimulator, atrial natriuretic peptide (ANP), would act synergistically to increase cGMP levels and blunt hypoxic pulmonary hypertension in rats, because these compounds act via different mechanisms to increase the intracellular second messenger. Acute hypoxia: Adult Sprague-Dawley rats were gavaged withSildenafil Citrate (Viagra) (1 mg/ kg) or vehicle and exposed to acute hypoxia with and without ANP (10(-8)-10(-5) M ).Sildenafil Citrate (Viagra) decreased systemic blood pressure (103 +/- 10 vs. 87 +/- 6 mm Hg, P < 0.001) and blunted the hypoxia-induced increase in right ventricular systolic pressure (RVSP; percent increase 73.7% +/- 9.4% in sildenafil-treated rats vs. 117.2% +/- 21.1% in vehicle-treated rats, P = 0.03). Also, ANP andSildenafil Citrate (Viagra) had synergistic effects on blunting the hypoxia-induced increase in RVSP (P < 0.001) and on rising plasma cGMP levels (P < 0.05). Chronic hypoxia: Other rats were exposed to prolonged hypoxia (3 weeks, 0.5 atm) after subcutaneous implantation of a sustained-release pellet containing lower (2.5 mg), or higher (25 mg) doses of sildenafil, or placebo. Higher-dose, but not lower-doseSildenafil Citrate (Viagra) blunted the chronic hypoxia-induced increase in RVSP (P = 0.006). RVSP and plasmaSildenafil Citrate (Viagra) levels were inversely correlated in hypoxic rats (r(2) = 0.68, P = 0.044). Lung cGMP levels were increased by both chronic hypoxia and sildenafil, with the greatest increase achieved by the combination. Plasma and right ventricular (RV) cGMP levels were increased by hypoxia, butSildenafil Citrate (Viagra) had no effect. RV hypertrophy and pulmonary artery muscularization were also unaffected by sildenafil. In conclusion,Sildenafil Citrate (Viagra) and ANP have synergistic effects on the blunting of hypoxia-induced pulmonary vasoconstriction. During chronic hypoxia,Sildenafil Citrate (Viagra) normalizes RVSP, but in the doses used,Sildenafil Citrate (Viagra) has no effect on RV hypertrophy or pulmonary vascular remodeling

Sildenafil improves acquisition and retention of memory in mice.

Sildenafil Citrate (Viagra) has been introduced recently in market to correct male impotency and has gained immense popularity for its dramatic effects all over the world. The present study was designed to investigate the effect ofSildenafil Citrate (Viagra) on learning and memory in mice using elevated plus maze. A total of XV groups of animals were employed in the present study. Central cholinergic pathways play a crucial role in learning and memory processes. Physostigmine, an anticholinesterase agent (0.5 mg, 1.0 mg kg(-1), i.p) was employed for its memory enhancing property and alprazolam a benzodiazepine receptor agonist served as a memory-impairing agent. In the present study, alprazolam produced anterograde amnesia (at 0.5 mg kg(-1), i.p) and retrograde amnesia (at 0.25 mg, 0.5 mg, 0.75 mg kg(-1), i.p.) in separate groups of animals. Caffeine at 5 mg, 10 mg and 20 mg kg(-1), i.p. (an established psychostimulant) did not show any significant change in learning and memory of mice.Sildenafil Citrate (Viagra) (at 8 mg kg(-1), i.p.) administered 30 minutes prior to training on first day produced a marginal decrease in transfer latency time on first day; whereas,Sildenafil Citrate (Viagra) (at 2 mg, 4 mg, 8 mg kg(-1), i.p.) administered immediately after training on first day produced a dose-dependent improvement of memory in mice. However, further studies need to be carried out to elucidate the underlying mechanism ofSildenafil Citrate (Viagra) as a memory enhancer

Identification of a new analogue ofSildenafil Citrate (Viagra) added illegally to a functional food marketed for penile Erectile Dysfunction.

A new analogue ofSildenafil Citrate (Viagra) was discovered to have been added illegally to a functional food marketed for penile Erectile Dysfunction. The structure of the analogue was established by various NMR spectroscopic techniques (including DEPT, COSY, TOCSY, HMQC, HMBC). Because of the addition of a methylene group to sildenafil, the main ingredient of Viagra(R), it was given the name homosildenafil, and this has never been reported previously. An analytical method using HPLC was proposed. Homosildenafil was added as a new inspection item and other foods have since been discovered to contain it

Vaginal Sildenafil Citrate (Viagra): a preliminary report of a novel method to improve uterine artery blood flow and endometrial development in patients undergoing IVF.

Endometrial growth is thought to depend on uterine artery blood flow and the importance of endometrial development on in-vitro fertilization (IVF) outcome has been previously reported. Nitric oxide (NO) relaxes vascular smooth muscle through a cGMP-mediated pathway and NO synthase isoforms have been identified in the uterus. Sildenafil Citrate (Viagra) (Viagra), a type 5-specific phosphodiesterase inhibitor, augments the vasodilatory effects of NO by preventing the degradation of cGMP. In this preliminary report we describe the use of vaginalSildenafil Citrate (Viagra) to improve uterine artery blood flow and sonographic endometrial appearance in four patients with prior failed assisted reproductive cycles due to poor endometrial response. The uterine artery pulsatility index (PI) was measured in a mock cycle after pituitary down-regulation with Lupron. The PI was decreased after 7 days ofSildenafil Citrate (Viagra) (indicating increased blood flow) and returned to baseline following treatment with placebo. The combination ofSildenafil Citrate (Viagra) and oestradiol valerate improved blood flow and endometrial thickness in all patients. These findings were reproduced in an ensuing gonadotrophin-stimulated cycle. Three of the four patients conceived. Although greater numbers of patients and randomized evaluation are needed to validate this treatment, vaginalSildenafil Citrate (Viagra) may be effective for improving uterine artery blood flow and endometrial development in IVF patients with prior poor endometrial response.