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Also known as:  Sildenafil Citrate.

Description

Viagra is an anti-impotence drug which enables men to achieve and sustain an erection.

The active ingredient of Viagra is Sildenafil Citrate (PDE-5 inhibitor). In response to sexual arousal, Sildenafil Citrate stimulates the release of nitric oxide (NO) in the corpus cavernosum. Nitric oxide activates the lyase enzyme which is followed by increasing levels of cyclic guanosine monophosphate (cGMP). This cyclic nucleotide relaxes smooth muscles in blood vessels of the corpus cavernosum, increasing blood flow and thus inducing an erection.

Along with the treatment of erectile disorders, Viagra effectively prolongs sexual performance, preventing premature ejaculation (PE).

Sildenafil Citrate is also used in the treatment of PAH (pulmonary arterial hypertension).

Viagra is also known as Aphrodil, Caverta, Kamagra, Suhagra, Edegra, Erasmo, Penegra, Revatio, Supra, Silagra, Zwagra.

Viagra does not protect you or your partner from sexually transmitted diseases (including HIV) or from pregnancy.

Dosage

Take one Viagra pill orally with a full glass of water, 30-60 minutes before sex.

The dosage depends on the overall health of the patient. Do not take more than one pill per day.

Take Viagra on an empty stomach, as fatty meals, grapefruit juice and alcohol can interfere with the effectiveness of the medication.

Overdose

If you take an overdose of Viagra, you should seek emergency medical attention or contact your healthcare provider immediately.

Storage

Store at room temperature between 15 and 30 degrees C (59 and 86 degrees F) and away from excess moisture and heat. Throw away any unused medicine after the expiration date. Keep out of the reach of children.

Side effects

The most common side effects associated with Viagra are:

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Side effect occurrence does not only depend on medication you are taking, but also on your overall health and other factors.

Contraindications

Do not take Viagra if you are allergic to any of Viagra’s components.

Do not take Viagra if you are also using organic nitrates, nitrate drugs for chest pain or heart condition (e.g., nitroglycerin, isosorbide dinitrate and isosorbide mononitrate), nitrates as amyl nitrate or nitrite ("poppers").

Do not take Viagra if you take other medications to treat erectile dysfunction or pulmonary arterial hypertension, such as riociguat (Adempas).

Do not take Viagra if you are taking erythromycin, alpha-blockers, ketoconazole, itraconazole (Sporanox or Nizoral), ritonavir (Norvir) or indinavir (Crixivan).

Do not consume alcohol while using Viagra, as it can lower your blood pressure, causing dizziness and rapid heart rate (tachycardia).

Do not drive or operate machinery while taking the medication.

Contact you doctor or health care professional right away if your erection lasts longer than 4 hours or if it becomes painful.

Viagra does not protect you or your partner from sexually transmitted diseases or pregnancy.

Viagra can be dangerous for children and women.

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Sildenafil improved objective and self-assessed erectile function in men with ED, and the duration of action of sildenafil was longer than that previously reported. These data suggest that sildenafil may be effective in a significant proportion of men with ED up to 12 hours after being taken.

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The data support the proposal that enhancement of penile erection by sildenafil in patients with erectile dysfunction involves potentiation of the NO-stimulated cGMP signal mediating relaxation of cavernosal smooth muscle during sexual stimulation. Sildenafil is a potent inhibitor of PDE5 from HCC, with high selectivity for PDE5 relative to other PDE isozymes.

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Patients with extensive lymphatic malformations associated with tissue overgrowth syndromes (such as Klippel-Trenaunay syndrome and CLOVES) often pose a therapeutic challenge for physicians. In recent years, it has been suggested that oral sildenafil therapy might be used to treat congenital lymphatic malformations. However, this possible new therapy has not yet been used in patients with lymphatic malformations associated with tissue overgrowth syndromes. A 30-year-old man with extensive capillary-lymphatic malformations of the right leg and thorax, and a tissue overgrowth syndrome caused by a somatic mutation in the PIK3CA gene, was treated with oral sildenafil due to symptoms of pain, dyspnea, and functional impairment. Several weeks after the start of the treatment, the patient reported softening of the lymphatic malformation and a significant improvement of his symptoms and physical condition. So far, sildenafil is still considered a last resort in the treatment of complex treatment-resistant lymphatic malformations. With this case report, we demonstrate that sildenafil could also be an alternative treatment option for lymphatic malformations in patients with syndromes belonging to the PIK3CA-related overgrowth spectrum.

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The prevalence of heart failure with preserved ejection fraction is increasing. The prognosis worsens with pulmonary hypertension and right ventricular (RV) failure development. We targeted pulmonary hypertension and RV burden with the phosphodiesterase-5 inhibitor sildenafil.

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Sildenafil only at its highest concentration was effective in suppressing NE induced pulmonary vessel contraction. Bosentan was able to completely suppress ET-1 induced contraction of PA and strongly attenuated contraction of PV. The present data suggest a benefit of sildenafil/bosentan combination therapy as they affect different pathways and may allow lower dosages.

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According to Indian Systems of Medicine, Spilanthes acmella (L.) Murr. (Family - Asteraceae), is considered effective in the treatment of sexual deficiencies especially due to ageing. In the present study, characterization of ethanolic extracts of the Spilanthes acmella flower and its effect on general mating pattern, penile erection and serum hormone levels of normal male Wistar albino rats were investigated and compared with sildenafil citrate. In vitro nitric oxide release was also investigated in human corpus cavernosum cell line. As N-alkylamides are a promising group, their profiling was performed using a gradient reversed phase high performance liquid chromatography/electrospray ionization ion trap mass spectrometry (HPLC/ESI-MS) method on an embedded polar column. MS(1) and MS(2) fragmentation data were used for identification purposes. For assessment of sexual behavior, animals were divided into five groups of eight male rats. The extracts (50, 100 and 150mg/kgbodyweight/day) and sildenafil citrate (5mg/kgbodyweight/day) (positive control) were administered orally for 28 days. The behavioral and sexual parameters were observed at days 0, 15, 28 and after a lapse of 7 and 14 days of discontinuance of drug treatment. Five N-isobutylamides, one 2-methylbutylamide and one 2-phenylethylamide were identified. The orally administered extract had a dose dependent positive effect on mounting frequency, intromission frequency and ejaculation frequency and the most significant effects (p<0.05) were observed at 150mg/kg treatment, even after a lapse of 7 and 14 days of discontinuance of drug treatment. A dose dependent effect was also observed on the FSH, LH and testosterone serum levels. With 150mg/kg of ethanolic extract the values for FSH, LH and testosterone were 3.10±0.25mlU/ml, 6.87±0.18mlU/ml and 3.72±0.12ng/ml, respectively. In vitro nitric oxide release was 21.7±2.9μM, which was significantly higher compared to the control group (p<0.01). Sildenafil citrate exhibited also a significant effect on NO release, but no effect on hormone levels of rats was observed. The aphrodisiac potential of an ethanolic Spilanthes acmella extract was demonstrated in vitro and in vivo. N-Alkylamides might attribute to the improved sexual potential. Study lends support to the traditional utilization of S. acmella as a sexual stimulating agent.

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Despite no direct association with sildenafil use and quality-of-life scores, sildenafil may be a beneficial treatment for antidepressant-induced sexual dysfunction. A double-blind, placebo-controlled study of sildenafil in antidepressant-induced sexual dysfunction is needed to further explore its potential benefits.

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Oral sildenafil represents a useful adjunctive therapy for patients with LVADs. In our series, it provided additional reduction of pulmonary artery pressure, and facilitated weaning from INO and inotropes without deleterious hemodynamic consequences.

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Although the cost-effectiveness of Viagra for the treatment of patients with erectile dysfunction is favourable, both public and political opinions seem to be inclined not to fund, or merely to partially fund (i.e. by reimbursing only specific patient groups) this medicine. This shows that in funding discussions, cost-effectiveness information is not solely decisive. In a theoretical framework for choices in health care that was developed in The Netherlands (the Dunning report, 1991), two other criteria besides cost-effectiveness were put forward as being important for rationing decisions: "necessary care" and "individual responsibility". Overlooking the Viagra discussion, many of the arguments put forward seemed to be related to these two criteria. However, a clear operationalisation of the criteria necessary care and individual responsibility is lacking, which makes it difficult to use the arguments in funding decisions. In this paper, we try to demonstrate how these criteria were presented in the Viagra discussion and we will indicate how these criteria can be operationalised in relation to the outcomes of a cost-effectiveness analysis.

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The regulatory role of nitric oxide (NO) in vaginal perfusion remains unclear. We used specific inhibitors of enzymes in the NO-cyclic GMP (NO-cGMP) pathway and investigated their effects on vaginal blood flow in the rabbit. NO synthase (NOS) activity was similar in both the proximal and distal rabbit vagina; whereas, arginase activity was 3.4-fold higher in the distal vagina. Intravenous administration of the NOS inhibitor L-NAME resulted in a 66% reduction in genital tissue oxyhemoglobin and a 53% reduction in vaginal blood flow. This attenuation occurred despite a 20-30% increase in systemic arterial pressure. The arginase inhibitor ABH caused a 2.1-fold increase in genital tissue oxyhemoglobin and 34% increase in vaginal blood flow. The guanylate cyclase inhibitor 1H-[1,2,4]oxadiazolo[4,3,-a]quinoxalin-1-one and the phosphodiesterase type 5 inhibitor sildenafil caused in a 37% reduction and a 44% increase in vaginal blood flow, respectively. These observations suggest that the NO-cGMP pathway is an important regulator of vaginal hemodynamics.

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Oral sildenafil was well tolerated and led to an improved clinical condition and exercise performance. Whether the drug improves mortality remains to be established. Larger trials a rewarranted.

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buy internet viagra 2016-01-21

The aim of this study was to investigate the effect of varying doses of sildenafil on the p50 of the oxygen-hemoglobin dissociation curve in blood samples from eight ( Alprostadil Pills 8) healthy adult male volunteers with normal hemoglobin HbAA.

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To investigate the protective effects of sildenafil citrate (SC) on indomethacin-induced gastric ulcer in a rat model. Lioresal 50 Mg

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With respect to urinary symptoms, a direct comparison cannot be made between the International Prostate Symptom Score and the RTOG late toxicity score. Nonetheless, it was Zantac 60 Mg evident that patients who underwent brachytherapy had more severe urinary sequelae in the months after implantation. Tamsulosin was still being used by 78% of patients at 6 months, decreasing to 55% at 1 year and 27% at 2 years. Intermittent self-catheterization was required at 6 months after treatment by 5% of patients who underwent brachytherapy, and a transurethral resection of the prostate was performed in one of these patients at 12 months. In patients who underwent 3D-CRT, 14% used tamsulosin at some point in the follow-up period and none required catheterization or transurethral resection of the prostate. In the bowel domain, 20% of patients who underwent brachytherapy experienced grade 1 gastrointestinal toxicity, most within the first 12 months of follow-up, compared with 30% grade 1 or 2 gastrointestinal scores in the 3D-CRT group (peaking in the second year after treatment). In the sexual domain, 9% of patients who underwent brachytherapy who were previously potent reported a loss of potency by 18 months, compared with 53% of patients who underwent 3D-CRT. Without the help of sildenafil (Viagra), these figures rose to 24% and 58%.

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A total of 42 male Wistar-albino rats were randomly assigned to the control group (n=21) or the study group (n=21). The control group Keflex Liquid Suspension was fed on a standard laboratory diet until 12 h before surgery, whereas the study group received Sildenafil citrate via orogastric tube 10 mg/kg once a day for 30 days. Under anaesthesia, a 3 x 3 x 2 mm depth defect was made on tibia of each rat. 7 animals from each group were euthanised on postoperative days 7,15 and 30. Bone samples were taken for examination, histologically on day 7, by 3D dental tomography on day 15, and for bone strength resistance on day 30.

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Sildenafil is a selective phosphodiesterase-5 inhibitor used for the treatment of erectile dysfunction and pulmonary hypertension. Sildenafil citrate monohydrate was complexed with α-, hydroxypropyl-β- and γ-cyclodextrin (α-CD, HP-β-CD and γ-CD, respectively) to enhance its water solubility. The complexes of sildenafil citrate monohydrate with all types of CDs were characterized by phase solubility diagrams, (1)H and (13)C NMR, and dielectric constants. Sildenafil citrate monohydrate complexed with CDs was developed as nanosuspensions for use in a pressurized metered-dose inhaler (pMDI). Sildenafil citrate monohydrate pMDI formulations were prepared by a bottom-up process using dried ethanol as a solvent and HFA-134a as an antisolvent and propellant in order to form nanosuspensions. A 3×3 factorial design was applied for the contents of the dried ethanol and HFA-134a propellant. The phase solubility profiles of the sildenafil and cyclodextrins were described as AL type with a mole ratio 1:1. The piperazine moiety of sildenafil formed an inclusion in the cavity of the CDs. The particle diameters of the sildenafil citrate monohydrate suspensions in pMDIs were all within a nanosuspension size range. An assay of the sildenafil content showed that the formation of complexes with CDs was close to 100%. In the case of the formulations with CDs, the emitted doses varied within 97.4±10.8%, the fine particle fractions (FPFs) were in a range of 45-81%, the fine particle dose (FPD) was 12.6±2.0 μg and the mass median aerodynamic diameters (MMADs) were 1.86±0.41 μm. In contrast, the formulations Protonix Pill without CDs produced a low emitted dose of sildenafil (<60%). Therefore, only sildenafil citrate monohydrate pMDI formulations containing CDs were suitable for use as aerosols.

generic viagra doses 2015-11-09

This study aimed at developing and validating an HPLC method for the assay of sildenafil citrate and its related substances that might coexist in the drug commercial products and in tablets' formulation as impurities that originate from synthesis processes or degradation. A chromatographic system comprising a microBondapak C(18) (10 microm) column, a mobile phase of ammonium acetate (pH 7.0, 0.2 M)-acetonitrile (1:1, v/v), a flow rate of 1 ml/min and a UV detector set at 240 nm has shown good chromatographic separation for sildenfil and the other related substances. The degree of linearity of the calibration curves, the percent recoveries of sildenafil and related substances, the limit of detection, LOD, and limit of quantitation, LOQ for the HPLC method have been determined. The HPLC method under Zocor Dose Limitations study was found to be specific, precise, accurate, reproducible indicating stability and robust.

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Mean age was 68 years. All patients completed the study. For most questions of the IIEF questionnaire there was Glucotrol Dosage a significant increase in mean scores from baseline with sildenafil, but not with placebo. Ninety percent of the patients needed a dose adjustment to 100 mg sildenafil. Side effects were mild or moderate.

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Erectile dysfunction (ED) commonly affects the quality of life of men after treatment of prostate cancer. We conducted a placebo-controlled, crossover randomised trial to assess the efficacy and tolerability of sildenafil citrate in the treatment of ED developing after external beam radiation treatment (EBRT) of localized prostate cancer. Sixty-six patients who had developed ED following radiation treatment agreed to participate and were allocated to sildenafil or placebo to be taken prior to four sexual attempts. In the crossover period, subjects received the alternative tablet for a further four attempts. Allocation was centrally randomized, and researchers and patients were both blinded to the trial arm. Efficacy was assessed using the International Index of Erectile Function (IIEF) questionnaire and with a separate global efficacy question. Forty-three subjects completed the study. There was a significant increase in mean scores from baseline Trandate 100 Mg for all domains of the IIEF with sildenafil compared with placebo (P < 0.001). Affirmative response to the global efficacy question was more common after taking sildenafil compared with placebo. In approximately half of the patients, the improvement in the erectile function domain score corresponded to a moderate improvement in ED (e.g. success 'sometimes' to 'most times'). Sildenafil was associated with mild flushing, nasal stuffiness or indigestion in 8-10% patients and moderate flushing in 10%. The current study adds to the evidence that phosphodiesterase inhibitors are an effective and well-tolerated treatment for ED after EBRT for prostate cancer.

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Two electroconvulsive tests were used: maximal electroshock seizure threshold (MEST) and maximal electroshock seizure (MES) tests in mice. Acute Prandin Diabetes Medication adverse effects of the studied combinations were investigated in the chimney test, step-through passive avoidance task, and grip-strength test. Total brain and free plasma concentrations of AEDs were also determined.

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A rapid, sensitive and reproducible HPLC method was developed and validated for the analysis of pantoprazole (CAS 102625-70-7) in human plasma. The separation was achieved on a monolithic silica column using acetonitrile-potassium dihydrogen phosphate Cipro Drug Information buffer (25:75,v/v), pH 3.0, as the mobile phase at a flow rate of 1.5 ml min(-1). The wavelength was set at 290 nm. The assay enables the measurement of pantoprazole for therapeutic drug monitoring with a minimum quantification limit of 20 ng ml(-1). The method involves a simple protein precipitation procedure. Analyticil recovery was complete. The calibration curve was linear over the concentration range 20-3500 ng ml(-1) The coefficients of variation forthe inter-day and intra-day assay were found to be less than 7%.

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The first 21 items from the UCSD compose a unidimensional dyspnea-with-activity scale and are both sensibly ordered and distinguished from each other by their METS values. These 21 items can be used confidently to formulate clinically-relevant inferences about IPF patients and should be considered for use as a meaningful endpoint in IPF research.

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A total of 976 men (64%) responded to the questionnaire. The internal consistency of the questionnaire construct was confirmed, with a Cronbach's alpha coefficient of 0.96 for all 5 questions. Eighty-nine percent of men younger than 50 years were sexually active compared with 37% of men older than age 80. Twenty-six percent of sexually active men reported complete (3%), severe (10.5%), or moderate (12.6%) ED. The prevalence of moderate or complete ED increased with age and was reported by 58% of men aged 75 to 79 years. Eleven percent of sexually active men had used sildenafil one or more times, with 63% reporting good or "terrific" effects and 11% reporting no benefit. The response to sildenafil deteriorated with age and increasing degree of ED.

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Type 5 phosphodiesterase inhibitors (5-PDEI), which have been applied as the basic medication for erectile dysfunction, are now being studied in various areas of clinical medicine (pulmonology, cardiology, gastroenterology, gynecology etc.) This systematic literature review is dedicated to 5-PDEI, the state of the problem, the prospects of clinical application of sildenafil, and is based upon 450 literature sources from MEDLINE database (from 1954 to June 2006) and the Cochrane Collaboration database (from 1977 to March 2005) found by key words sildenafil, phosphodiesterase, and 5-PDEI. The issues of physiology and pathophysiology of 5-PDEI, the historical background of their creation, the appropriateness and efficacy of sildenafil in pulmonary arterial hypertension are considered in Part I of the review.