Screening for potentially transmitting sexual risk behaviors, urethral sexually transmitted infection, andSildenafil Citrate (Viagra) use among males entering care for HIV infection.

The study aims were to evaluate the prevalence and predictors of sexual risk behaviors and urethral sexually transmitted disease (STD) among males entering care for HIV infection and to examine ifSildenafil Citrate (Viagra) prescriptions are associated with potentially transmitting sexual risk behavior (PTSRB). The research design included (1) self-administered questionnaire of symptoms of sexually transmitted infection (STI), number of recent sex partners, unprotected sexual risk behaviors, use of drugs/alcohol during sex, and HIV disclosure; (2) urine gonorrhea/chlamydia polymerase chain reaction (PCR); and (3) record review forSildenafil Citrate (Viagra) prescriptions. A PTSRB was defined as insertive anal, vaginal, or oral sex without a condom. Between March 2001 and March 2002, 413 entrants were surveyed. The prevalence of positive urine PCR among those with and without urethral symptoms was 16.7% and 2.4%, respectively. Fifty-one percent met criteria for PTSRB during the preceding month. Those reporting PTSRB were more likely to report multiple partners. In a multiple logistic regression model, the following were significant (p < 0.05) predictors of PTSRB: drug or alcohol use during sex; white race; only male partners, andSildenafil Citrate (Viagra) use. Drug use during sex was associated both with more sex partners and more sexual risk behaviors. Always disclosing HIV status was associated with fewer partners. There was a high prevalence of PTSRB among HIV-infected males entering care. Men who have sex with men (MSM), white race, drug/alcohol use during sex, andSildenafil Citrate (Viagra) use were independent risk factors. PTSRB was associated with having multiple partners. Physicians should discuss risk behaviors before prescribingSildenafil Citrate (Viagra)

Comparative human pharmacokinetics and metabolism of single-dose oral and intravenous sildenafil.

AIMS: To characterize the absorption, metabolism and excretion of an oral and intravenous (IV) dose of radiolabelled [14C]-Sildenafil Citrate (Viagra) in healthy male subjects. Specific objectives were to measure the cumulative amount of drug-related radiolabelled material excreted in the urine and faeces to characterize urinary and faecal radioactivity as unchangedSildenafil Citrate (Viagra) or its metabolites, and to quantify blood and plasma total radioactivity and unchanged drug concentrations. METHODS: Six healthy male subjects between the ages of 45 and 58 years were enrolled in an open-label, parallel-group study; three subjects received the oral dose and three received the IV dose. Oral drug was administered as a single dose of 50-mg [14C]-sildenafil, and IV drug was administered as a single dose of 25-mg [14C]-sildenafil infused over 25 min. Each dosage form contained 50 microCi of radioactivity. For radioactivity assays, whole blood, plasma, urine and faeces samples were taken predose and at specified intervals up to 5 days postdose. Plasma samples were assayed forSildenafil Citrate (Viagra) and the metabolites UK-103,320 and UK-150,564. Metabolite profiling was also performed in plasma, faeces and urine. RESULTS: Absorption ofSildenafil Citrate (Viagra) after oral administration was rapid and approximately 92% whilst the absolute bioavailability was limited to 38%, due to first-pass metabolism. Mean AUCt values showed thatSildenafil Citrate (Viagra) accounted for about 60% of the total circulating radioactivity in the plasma after IV administration and for 32% after oral administration. Concentrations of radioactivity in whole blood were lower than in plasma, indicating limited penetration ofSildenafil Citrate (Viagra) into blood cells. No unchangedSildenafil Citrate (Viagra) was detected in either urine or faeces, demonstrating that metabolism was the major mechanism of drug clearance. The principal routes of metabolism were N-demethylation, oxidation and aliphatic dehydroxylation.Sildenafil Citrate (Viagra) was well tolerated, with treatment-related adverse events reported by three subjects. Two of these were mild, and there was one case of moderate leg pain. CONCLUSIONS: The pharmacokinetics of radiolabelled [14C]-sildenafil were consistent with rapid absorption, first-pass metabolism and primarily faecal elimination of N-demethylated metabolites

The effect ofSildenafil Citrate (Viagra) on electrostimulation-induced erection in the rat model.

This study was conducted to show the effect ofSildenafil Citrate (Viagra) on electrostimulation-induced erection in the rat model. Fifteen 12-week-old male Wistar Kyoto rats were used. The intracavernous pressure and arterial blood pressure were simultaneously monitored through electric cavernous nerve stimulation before and after the administration ofSildenafil Citrate (Viagra) (2 mg/kg). Statistical analysis was performed on maximal intracavernous pressure (MIP), mean arterial blood pressure (MAP), the MIP/MAP and detumescence time. MAP decreased significantly by about 20 mmHg afterSildenafil Citrate (Viagra) administration. The MIP/MAP increased significantly afterSildenafil Citrate (Viagra) administration. The effect ofSildenafil Citrate (Viagra) on the MIP/MAP was marked especially at lower (2-3 Hz) frequencies. The detumescence time significantly increased afterSildenafil Citrate (Viagra) administration. We have shown thatSildenafil Citrate (Viagra) is effective for enhancing erection at lower frequencies and prolonging penile erection in rats. After the administration of sildenafil, penile erection would be induced by weak stimuli that will not cause penile erection under normal conditions

Cost-sharing for prescriptions ofSildenafil Citrate (Viagra) and finasteride: a case study in veteran patients.

OBJECTIVE: To evaluate patients willingness to share the costs of 2 medications (often described as "lifestyle medications"):Sildenafil Citrate (Viagra) for Erectile Dysfunction and finasteride for hair loss, which are not routinely covered by the Department of Veterans Affairs (VA) healthcare system. STUDY DESIGN: Self-administered, anonymous survey. PATIENTS AND METHODS: Adult men (n = 339) were recruited from waiting rooms for primary care or Erectile Dysfunction clinic appointments at 2 Los Angeles VA facilities. RESULTS: Participants with self-reported need were analyzed separately for finasteride (primary care patients only) andSildenafil Citrate (Viagra) (both primary care and Erectile Dysfunction clinic patients). The mean age of the participants was 56 and 60 years for the finasteride andSildenafil Citrate (Viagra) groups, respectively. Mean annual household income for both groups was under $10,000. Respondents reported a mean willingness to cost-share $4.20 for a 30-day prescription of daily finasteride (VA wholesale cost = $27) and $5.40 for 4Sildenafil Citrate (Viagra) pills (VA wholesale cost = $20). In the multivariate analysis, higher income (P = .002) and increasing self-reported need for medication (P = .04) were associated with increased willingness to cost-share for finasteride after controlling for age, race/ethnicity, insured status, comorbid conditions, and type of clinic. In addition, younger age (P = .01) was associated with greater willingness to cost-share for sildenafil. CONCLUSIONS: In this low-income veteran population, patients with a self-reported need forSildenafil Citrate (Viagra) and finasteride would be willing to make a higher copayment than the current VA maximum copayment of $2.00 per 30-day prescription, if these medicines were made available

The effect ofSildenafil Citrate (Viagra) on human platelet secretory function is controlled by a complex interplay between phosphodiesterases 2, 3 and 5.

Human platelets contain the cyclic nucleotide-hydrolyzing phosphodiesterases (PDEs) 2, 3 and 5. The cGMP-PDE5 inhibitorsSildenafil Citrate (Viagra) and Zaprinast have been demonstrated to potentiate the anti-platelet aggregatory effect of NO donors like sodium nitroprusside (SNP) in vitro but the mechanisms of Sildenafil's action on the secretory function of human platelets have not been analysed in detail. In the present paper, we show (1) that both compounds potentiate the SNP-induced increase in cGMP in human platelets concentration-dependently. (2) However, whereasSildenafil Citrate (Viagra) plus SNP treatment only partially inhibits thrombin-induced release of serotonin, the less selective Zaprinast plus SNP cause a complete inhibition. (3) The inhibition mediated bySildenafil Citrate (Viagra) plus SNP is limited to low compound concentrations at which cAMP levels are increased, probably due to cGMP-mediated inhibition of PDE3. (4) High concentrations ofSildenafil Citrate (Viagra) (plus SNP) neither affect cAMP levels, likely due to the activation of PDE2, nor inhibits the release of serotonin. Thus, increases in both cyclic nucleotides seem to control platelet function. (5) Accordingly, treatment with increasing concentrations ofSildenafil Citrate (Viagra) plus SNP and a selective PDE2 inhibitor, which by its own has no effect, induced a concentration-dependent increase in cAMP and complete inhibition of platelet activation. In summary, our data indicate thatSildenafil Citrate (Viagra) inhibits secretory function of human platelets at least in part due to the cGMP-mediated effects on intracellular cAMP and that entire inhibition of serotonin release from thrombin-activated platelets is controlled by both cyclic nucleotides

Stimulation of serotonin transport by the cyclic GMP phosphodiesterase-5 inhibitor sildenafil.

The serotonin (5-hydroxtryptamine, 5-HT) transporter (SERT) plays a critical role in the inactivation of synaptic 5-HT and has been implicated in multiple psychiatric and peripheral disorders. SERT regulation studies demonstrate that activation of cyclic guanosine monophosphate (cGMP)/protein kinase G (PKG)-linked pathways can increase SERT activity. As cGMP actions are limited by cGMP-specific phosphodiesterase (PDEs), we investigated whether the cGMP-specific PDE5 inhibitor Sildenafil Citrate (Viagra) can stimulate 5-HT uptake and potentiate cGMP-mediated regulation. In RBL-2H3 cells, SERT activity was stimulated bySildenafil Citrate (Viagra) in a concentration- and time-dependent manner.Sildenafil Citrate (Viagra) also enhanced the stimulation of SERT triggered by the adenosine receptor agonist 5'-N-ethylcarboxamidoadenosine (NECA), effects blocked by the PKG inhibitor N-[2-(methylamino)ethy]-5-isoquinoline-sulfonamide (H8).Sildenafil Citrate (Viagra) stimulation of 5-HT uptake arises from an increase in 5-HT transport Vmax and is paralleled by elevated SERT surface antagonist binding, also H8-sensitive. These findings implicate cGMP-targeted PDEs in limiting the regulation of antidepressant-sensitive 5-HT transport

Use of intraurethral alprostadil in patients not responding to Sildenafil Citrate (Viagra).

OBJECTIVES: To determine whether intraurethral alprostadil would be an effective alternative for men with Erectile Dysfunction who did not respond adequately to Sildenafil Citrate (Viagra) but desired minimally invasive treatment. METHODS: A total of 44 male patients aged 41 to 74 years with Erectile Dysfunction refractory to treatment with Sildenafil Citrate (Viagra) were enrolled in this study. Of the 44 patients, 10 had undergone prior radical retropubic prostatectomy. The patients were evaluated for subjective improvement in an office setting and completed the Sexual Health Inventory for Men questionnaire as an objective assessment of improved erectile ability. Success was defined as subjective improvement in erectile function, as well as an improved Sexual Health Inventory for Men score. RESULTS: Of the 44 men, 13 (29.5%) responded successfully to intraurethral alprostadil, with a follow-up ranging from 2 to 15 months. The remaining 31 men had no response (n = 28, 90%), refused escalating doses (n = 2, 7%), or were lost to follow-up (n = 1, 3%). In the subgroup of 10 men with prior radical retropubic prostatectomy, 5 (50%) reported success with intraurethral alprostadil (500 microg in 2 patients and 1000 microg in 3 patients). CONCLUSIONS: Although Sildenafil Citrate (Viagra) remains the most common initial therapy in men with Erectile Dysfunction, intraurethral alprostadil may be a reasonable treatment option forSildenafil Citrate (Viagra) nonresponders. This may be especially true in men having undergone prior radical retropubic prostatectomy.

Efficacy ofSildenafil Citrate (Viagra) as adjuvant therapy to selective serotonin reuptake inhibitor in alleviating premature ejaculation.

OBJECTIVES: To evaluate the efficacy ofSildenafil Citrate (Viagra) and selective serotonin reuptake inhibitor in alleviating premature ejaculation (PE) in patients in whom other treatments had failed. METHODS: Healthy men evaluated for primary PE graded their ejaculation on a scale of 0 to 8 (0 = almost never, 8 = almost always). The intravaginal ejaculatory latency time (IVELT) was graded on a scale of 0 to 3 (0 = longer than 5 minutes, 3 = shorter than 1 minute). The 138 men who scored their PE as 4 or greater and IVELT as 2 or greater comprised the study group. Psychological and behavioral counseling was provided during the study. PE was graded using the same scales 3 months after the initiation of each treatment. Topical 5% lidocaine ointment comprised the initial treatment: dissatisfied patients (PE grade 4 or greater, IVELT 2 or greater), took one tablet of paroxetine 20 mg for 30 days and then one tablet 7 hours before intercourse.Sildenafil Citrate (Viagra) was added to the treatment of patients dissatisfied with paroxetine alone. RESULTS: The mean initial PE grade was 5.67 +/- 0.13 and that for IVELT was 2.9 +/- 0.19 for all participants (mean age 28.7 years). Thirty-eight reported improvement (PE grade 2.0 +/- 0.8, P <0.01; IVELT 0.13 +/- 0.34, P <0.001) after local lidocaine application. Of the 100 treated with paroxetine, 42 reported improvement (PE grade 2.5 +/- 0.1, P <0.01; IVELT 0.28 +/- 0.46, P <0.001), and 56 of the remaining 58 who were treated with a combination of paroxetine andSildenafil Citrate (Viagra) reported improvement (PE grade 1.78 +/- 0.23, P <0.001; IVELT 0.16 +/- 0.37, P <0.001). Two patients remained dissatisfied with all treatment modalities. CONCLUSIONS:Sildenafil Citrate (Viagra) combined with paroxetine and psychological and behavioral counseling alleviated PE in patients in whom other treatments failed