sildenafil-citrate and Hypogonadism

sildenafil-citrate has been researched along with Hypogonadism* in 15 studies

Reviews

6 review(s) available for sildenafil-citrate and Hypogonadism

ArticleYear
Erectile dysfunction and testosterone deficiency.
    Frontiers of hormone research, 2009, Volume: 37

    A definitive role of testosterone in erectile function has been controversial; however, recent evidence is becoming available which substantiates a key function for this hormone. Testosterone deficiency is associated with a decline in erectile function and testosterone levels are inversely correlated with increasing severity of erectile dysfunction. Erectile dysfunction can be caused by multifactorial pathologies. In particular, erectile dysfunction may be the first symptom of cardiovascular disease. Animal studies have demonstrated that castration causes vascular smooth muscle cell atrophy, venous leakage, adipocytes in the subtunical space, loss of elastic fibers and increase in collagen deposition. Testosterone increases the expression of nitric oxide synthase and phosphodiesterase type 5, both principal enzymes involved in the erectile process. Testosterone replacement alone in hypogonadal men can restore erectile function. A significant proportion of men who fail to respond to a PDE5 inhibitor are testosterone deficient. Testosterone replacement therapy can convert over half of these men into phosphodiesterase type 5 responders. It is now recommended that testosterone levels should be assessed in all patients with erectile dysfunction.

    Topics: Animals; Erectile Dysfunction; Humans; Hypogonadism; Male; Nitric Oxide; Piperazines; Purines; Sildenafil Citrate; Sulfones; Testosterone

2009
Sexual function in chronic kidney disease.
    Advances in chronic kidney disease, 2007, Volume: 14, Issue:2

    Endocrine abnormalities are common in patients with chronic kidney disease (CKD) and lead to sexual dysfunction, anemia, hyperparathyroidism, and altered mineral metabolism. Common clinical problems include disturbances in menstruation in women, erectile dysfunction in men, and decreased libido and infertility in both sexes. Organic factors tend to be prominent and are related to uremia and other comorbid illnesses. Psychological factors and depression may exacerbate the primary problem. Alterations in the hypothalamic-pituitary axis are seen early in CKD and tend to worsen after patients start dialysis. Hypogonadism plays a dominant role in male sexual function, whereas changes in hypothalamic-pituitary function predominate in female sexual dysfunction. In patients on dialysis, treatment strategies include optimizing dose of dialysis, correction of anemia with erythropoietin, and correction of hyperparathyroidism. Successful kidney transplantation may restore normal sexual function, especially in younger patients.

    Topics: Androgens; Chronic Disease; Erythropoietin; Female; Hormone Replacement Therapy; Humans; Hypogonadism; Kidney Diseases; Kidney Transplantation; Male; Phosphodiesterase Inhibitors; Piperazines; Purines; Recombinant Proteins; Sexual Dysfunction, Physiological; Sildenafil Citrate; Sulfones; Testosterone

2007
Testosterone treatment to mimic hormone physiology in androgen replacement therapy. A view on testosterone gel and other preparations available.
    Expert opinion on biological therapy, 2007, Volume: 7, Issue:7

    There is still considerable controversy concerning the issue of testosterone replacement therapy. This is because testosterone replacement therapy is not a 'risk-free' treatment and a randomized controlled trial to evaluate safety of prolonged testosterone replacement therapy is not available, nor is it likely to be in the near future. However, recent testosterone delivery systems, such as the 1% gel (Testogel, Androgel and Testim), have proven to have a good physiologic profile, allowing constant monitoring of the possible complications and prompt discontinuation in the event of adverse effects. The aim of this paper is to provide a comprehensive review of the available testosterone preparations to treat male hypogonadism, with special interest in the treatment of ageing men and late-onset hypogonadism. In addition, the experimental and clinical data on the effect of testosterone on sexual function domains is reviewed along with the indication for the combination therapy of androgens with pro-erectile drugs, for example, type 5 phosphodiesterase inhibitors.

    Topics: 3',5'-Cyclic-GMP Phosphodiesterases; Cyclic Nucleotide Phosphodiesterases, Type 5; Drug Delivery Systems; Erectile Dysfunction; Gels; Hormone Replacement Therapy; Humans; Hypogonadism; Male; Piperazines; Purines; Sildenafil Citrate; Sulfones; Testosterone

2007
Depression and erectile dysfunction.
    The Urologic clinics of North America, 2007, Volume: 34, Issue:4

    Depression and erectile dysfunction (ED) clearly are associated. Although urologists and psychiatrists have long recognized that antidepressant medications affect erectile function negatively, the interplay between the two conditions remains underappreciated. Psychiatrists may be reluctant to question a patient in detail about ED, and urologists seldom perform a formal assessment of the presence of depression in patients who have ED. This article gives a quick overview of the relationship between these two conditions and provides the clinician with the knowledge required to effectively manage ED with comorbid depression.

    Topics: Antidepressive Agents; Depression; Erectile Dysfunction; Humans; Hypogonadism; Male; Phosphodiesterase Inhibitors; Piperazines; Purines; Sildenafil Citrate; Sulfones

2007
Testosterone therapy in erectile dysfunction and hypogonadism.
    The journal of sexual medicine, 2005, Volume: 2, Issue:6

    Laboratory experiments indicate that the nitric oxide erectile pathway is testosterone-dependent. Castration induces erectile dysfunction (ED) and reduction in nitric oxide synthase and in phosphodiesterase type 5 (PDE5) in the erectile tissue. Furthermore, castration causes apoptosis adversely affecting smooth muscle content and penile hemodynamics leading to veno-occlusive dysfunction. Testosterone therapy reverses these structural, biochemical, and physiological changes. In humans, testosterone therapy improves erectile function in men with hypogonadism. However, the efficacy of testosterone monotherapy may not be adequate because of the multifactorial nature of the pathophysiology of ED.. Preliminary data from a number of studies have been reviewed.. There are emerging evidence-based benefits to using the combination of testoterone and PDE5 inhibitors. A recently published multicenter, randomized, placebo-controlled study evaluated the safety and efficacy of testosterone gel 1% plus sildenafil vs. placebo gel plus sildenafil, in producing an erectile response in hypogonadal men who had failed prior sildenafil alone for ED. Screening yielded a prevalence of hypogonadism in ED patients who failed prior sildenafil. Following randomization, the double-blinded treatment phase was 12 weeks. Testosterone therapy with testosterone gel significantly improved erectile function in response to sildenafil. In addition, it significantly improved orgasmic function and patient satisfaction.. It is important to screen all men with ED for hypogonadism, especially those with a history of inadequate response to prior PDE5 inhibitors. The combination of testosterone plus PDE5 inhibitors may be considered for the treatment of ED in men with low to low-normal testosterone levels, who had inadequate response to prior treatment with PDE5 inhibitors alone.

    Topics: Androgens; Drug Therapy, Combination; Erectile Dysfunction; Gels; Humans; Hypogonadism; Male; Models, Animal; Phosphodiesterase Inhibitors; Piperazines; Purines; Sildenafil Citrate; Sulfones; Testosterone

2005
Current treatments and emerging therapeutic approaches in male erectile dysfunction.
    BJU international, 2001, Volume: 88 Suppl 3

    Topics: Adrenergic alpha-Antagonists; Alprostadil; Apomorphine; Erectile Dysfunction; Humans; Hypogonadism; Imidazoles; Male; Penile Implantation; Physical Therapy Modalities; Piperazines; Psychotherapy; Purines; Sildenafil Citrate; Sulfones; Testosterone; Triazines; Vacuum; Vardenafil Dihydrochloride; Vascular Surgical Procedures; Vasodilator Agents; Yohimbine

2001

Trials

3 trial(s) available for sildenafil-citrate and Hypogonadism

ArticleYear
Salivary 8-OHdG: a useful biomarker for predicting severe ED and hypogonadism.
    The journal of sexual medicine, 2008, Volume: 5, Issue:6

    Erectile and endothelial dysfunction are common pathologies of multiple cardiovascular risk factors and are considered longitudinal predictors of cardiovascular events. Oxidative stress and decreases in testosterone levels play an important role in the pathogenesis of endothelial dysfunction.. We sought to determine whether the severity of erectile dysfunction (ED) was associated with individual levels of testosterone and oxidative stress, and whether treatment with a phosphodiesterase type 5 inhibitor could reduce oxidative stress and increase testosterone availability.. We evaluated the association of salivary 8-hydroxy-2'-deoxyguanosine (8-OHdG), salivary testosterone, International Index of Erectile Function-erectile function domain (IIEF-EF) scores, and Medical Outcome Study (MOS) 36-item Short-Form Healthy Survey (SF-36) questionnaires in 128 middle-aged male volunteers. We investigated the changes in testosterone levels, salivary 8-OHdG levels, IIEF-EF scores, and SF-36 scores in 20 ED patients (according to the IIEF-EF) who took 50 mg of sildenafil once a week for 6 months.. IIEF-EF scores were used to assess ED severity. Antioxidant status was defined by salivary 8-OHdG. Salivary testosterone was used to evaluate serum bioavailable testosterone availability.. Salivary 8-OHdG (OR = 9.88, 95% CI: 1.52-64.10), salivary testosterone (Odds ratio [OR] = 0.96, 95% CI: 0.93-0.98), and vitality on the SF-36, version 2 (SF-36 v2) (OR = 0.92, 95%CI: 0.84-0.98) were significantly associated with the severity of ED in healthy volunteers. Treatment with sildenafil for 6 months significantly increased the total serum testosterone (426.4 +/- 174.8 vs. 569.6 +/- 146.1 ng/dL, P = 0.021) and salivary testosterone levels (56.1 +/- 22.3 vs. 110.0 +/- 48.4 pg/mL, P < 0.001), whereas it decreased salivary 8-OHdG levels (2.30 +/- 0.23 vs. 0.90 +/- 0.05 ng/mL, P = 0.0046).. Salivary 8-OHdG is a useful biomarker for predicting severe ED and hypogonadism in middle-aged men. Once-a-week treatment with sildenafil can have beneficial effects on men's health by decreasing oxidative stress and increasing testosterone levels.

    Topics: 8-Hydroxy-2'-Deoxyguanosine; Adult; Biomarkers; Cross-Sectional Studies; Deoxyguanosine; Erectile Dysfunction; Humans; Hypogonadism; Male; Middle Aged; Oxidative Stress; Phosphodiesterase Inhibitors; Piperazines; Purines; Saliva; Severity of Illness Index; Sildenafil Citrate; Sulfones; Surveys and Questionnaires; Testosterone

2008
Does sildenafil combined with testosterone gel improve erectile dysfunction in hypogonadal men in whom testosterone supplement therapy alone failed?
    The Journal of urology, 2005, Volume: 173, Issue:2

    We evaluated the efficacy of testosterone gel (T-gel) alone and in combination with sildenafil in hypogonadal patients with erectile dysfunction (ED).. A total of 49 hypogonadal men (mean age 60.7 years) with ED participated for a mean of 20.2 months. Blood was tested for total and bioavailable testosterone, and prostate specific antigen. Sexual function was assessed using the International Index of Erectile Function questionnaire and a global assessment question (GAQ). Men received 1% 5 gm T-gel for 6 months, and 100 mg sildenafil was added to those with a "no" response to the GAQ after 3 months on testosterone supplement.. A total of 31 patients reported significant improvement in the sexual desire domain (from a mean +/- SD of 4.2 +/- 0.8 to 8.6 +/- 0.4) and erectile function (EF) domain (from 13.6 +/- 1.9 to 27 +/- 0.8) following treatment with testosterone supplement alone. One patient was excluded from study after urinary retention developed and 9 reported irritation at the gel application site. In spite of normalization of total and bioavailable testosterone values, and significant improvement of sexual desire domain scores, the EF of 17 men remained less than 26 or they responded "no" to the GAQ. These men received combined T-gel and sildenafil, after which all graded EF greater than 26 and responded positively to the GAQ.. Combined treatment with sildenafil and T-gel has a beneficial effect on ED in hypogonadal patients in whom treatment with testosterone supplement alone failed.

    Topics: Adult; Aged; Androgens; Drug Therapy, Combination; Erectile Dysfunction; Gels; Humans; Hypogonadism; Male; Middle Aged; Phosphodiesterase Inhibitors; Piperazines; Prospective Studies; Purines; Sildenafil Citrate; Sulfones; Testosterone; Treatment Failure

2005
Randomized study of testosterone gel as adjunctive therapy to sildenafil in hypogonadal men with erectile dysfunction who do not respond to sildenafil alone.
    The Journal of urology, 2004, Volume: 172, Issue:2

    We compare the efficacy of testosterone gel (T-gel) versus placebo as adjunctive therapy to sildenafil in hypogonadal men with erectile dysfunction who do not respond to sildenafil alone.. A randomized, placebo controlled, double-blind, parallel group, multicenter study was performed. A total of 75 hypogonadal men (18 to 80 years old, morning serum total testosterone 400 ng/dl or less) with confirmed lack of response to sildenafil monotherapy were randomized (1:1) to receive a daily dose of 1% T-gel or 5 gm placebo gel as adjunctive therapy to 100 mg sildenafil during a 12-week period. Subjects were evaluated for sexual function, primarily based on the International Index of Erectile Function (IIEF), quality of life and serum testosterone levels at baseline and weeks 4, 8 and 12.. Testosterone treated subjects had greater improvement in erectile function compared to those who received placebo, reaching statistical significance at week 4 (4.4 vs 2.1, p = 0.029, 95.1% CI 0.3, 4.7). Similar trends were observed for improvements in orgasmic function, overall satisfaction, total IIEF score and percentage of IIEF responders. T-gel significantly (p < or =0.004) increased total and free testosterone levels throughout the study, although no significant correlations were made between testosterone levels and the IIEF at end point.. T-gel taken with sildenafil may be beneficial in improving erectile function in hypogonadal men with erectile dysfunction who are unresponsive to sildenafil alone.

    Topics: Adolescent; Adult; Aged; Aged, 80 and over; Double-Blind Method; Drug Therapy, Combination; Erectile Dysfunction; Gels; Humans; Hypogonadism; Male; Middle Aged; Phosphodiesterase Inhibitors; Piperazines; Purines; Quality of Life; Sildenafil Citrate; Sulfones; Testosterone; Treatment Failure

2004

Other Studies

6 other study(ies) available for sildenafil-citrate and Hypogonadism

ArticleYear
Testosterone partially ameliorates metabolic profile and erectile responsiveness to PDE5 inhibitors in an animal model of male metabolic syndrome.
    The journal of sexual medicine, 2009, Volume: 6, Issue:12

    Metabolic syndrome (MetS) is a clustering of cardio-metabolic risk factors (hyperglycemia, hypertension, dyslipidemia, visceral fat accumulation) that is also associated with hypogonadism and erectile dysfunction (ED).. To clarify the relationships among MetS, hypogonadism, and ED, we developed an animal model of MetS.. Male rabbits fed a high-fat diet (HFD), with or without testosterone (T) supplementation, were compared with control rabbits (fed a standard chow) and with rabbits made hypogonadal by a single injection of a long-acting GnRH-analog, triptorelin.. Evaluation of metabolic disturbances (plasma glucose, cholesterol, triglycerides, testosterone, LH, FSH level, glucose tolerance, mean arterial pressure, visceral fat accumulation), and corpora cavernosa (CC) relaxant capacity (in vitro contractility study) in HFD animals as compared with control, GnRH analog-treated rabbits, and T-supplemented HFD rabbits.. HFD rabbits showed all the features of MetS. HFD induced hypogonadotropic hypogonadism is characterized by a reduction of plasma T, FSH, LH levels, testis and seminal vesicles weight, and testicular steroidogenic enzymes. Such a phenotype is similar to that induced by triptorelin administration. A reduced GnRH immunopositivity in hypothalamus suggests a central origin of HFD-related hypogonadism. HFD also induced penile alterations, as demonstrated by a reduction of acetylcholine-and electrical field stimulation-induced CC relaxation, hyper-responsiveness to the NO donor, SNP, and unresponsiveness to PDE5 inhibitors. Similar penile alterations were observed in triptorelin treated rabbit. In HFD, as well as in triptorelin treated rabbits, PDE5 and eNOS mRNA expression quantitative reverse transcriptase-polymerase chain reaction (qRT-PCR) were significantly decreased. T administration prevented almost all penile alterations observed in HFD rabbits. T treatment dramatically reduced HFD-induced visceral obesity, partially ameliorating also the metabolic profile.. We have developed an animal model of MetS associated with hypogonadotropic hypogonadism and penile alterations including unresponsiveness to PDE5 inhibitors. T supplementation was able to partially revert HFD-induced phenotype.

    Topics: Animals; Blood Glucose; Disease Models, Animal; Drug Synergism; Erectile Dysfunction; Glucose Tolerance Test; Hypogonadism; Male; Metabolic Syndrome; Phosphodiesterase 5 Inhibitors; Phosphodiesterase Inhibitors; Piperazines; Purines; Rabbits; Sildenafil Citrate; Sulfones; Testosterone

2009
Testosterone restores diabetes-induced erectile dysfunction and sildenafil responsiveness in two distinct animal models of chemical diabetes.
    The journal of sexual medicine, 2006, Volume: 3, Issue:2

    Hypogonadism is often associated with diabetes and both conditions represent major risk factors for erectile dysfunction (ED).. To investigate the role of hypogonadism on phosphodiesterase type 5 (PDE5) expression and sildenafil responsiveness in diabetes.. Two different models of experimental diabetes were used: (i) alloxan-induced diabetic rabbit; and (ii) streptozotocin (STZ)-induced diabetic rat. In both experimental models, animals were separated into three groups: control, diabetic, diabetic supplemented with testosterone (T) enanthate. Rabbits were used for "in vitro" experiments. Conversely, each rats group was further subdivided: no further treatment or acute sildenafil dosing (25 mg/kg, 1 hour before "in vivo" electrical stimulation [ES]).. Erectile capacity was evaluated either by "in vitro" contractility study (alloxan-induced diabetic rabbit) and "in vivo" evaluation of erectile response elicited by ES of cavernous nerve (STZ-induced diabetic rats). Also endothelial nitric oxide synthase, neural nitric oxide synthase (nNOS), and PDE5 protein (Western blot) and mRNA (quantitative real-time reverse transcriptase polymerase chain reaction [RT-PCR]) expression were measured in rat penile samples of each group.. In both models, hypogonadism was observed, characterized by reduced T and atrophy of androgen-dependent accessory glands. T substitution completely reverted hypogonadism and diabetes-induced penile hyposensitivity to "in vitro" (acetylcholine, rabbit) or "in vivo" (ES, rat) relaxant stimuli, along with nNOS expression, which was reduced (P < 0.05) in STZ rats. In diabetic animals, T substitution reinstated sildenafil-induced enhancement of both "in vitro" nitric oxide donor (NCX 4040) relaxant effect (rabbit) and "in vivo" ES-induced erection (rat). PDE5 was reduced in diabetic STZ rats (P < 0.05) and normalized by T. In STZ rats, sodium nitroprusside (SNP) intracavernous injection induced a more sustained erection than in control rats, which was no further enhanced by sildenafil. T substitution normalized both hyper-responsiveness to SNP and sildenafil efficacy.. In two models of diabetes T deficiency underlies biochemical alterations leading to ED. Normalizing T in diabetes restores nNOS and PDE5, and reinstates sensitivity to relaxant stimuli and responsiveness to sildenafil.

    Topics: 3',5'-Cyclic-GMP Phosphodiesterases; Alloxan; Animals; Cyclic Nucleotide Phosphodiesterases, Type 5; Diabetes Mellitus, Experimental; Disease Models, Animal; Endothelium, Vascular; Erectile Dysfunction; Hypogonadism; Male; Nitric Oxide Synthase; Penile Erection; Phosphoric Diester Hydrolases; Piperazines; Purines; Rabbits; Rats; Rats, Sprague-Dawley; Reverse Transcriptase Polymerase Chain Reaction; Sildenafil Citrate; Streptozocin; Sulfones; Testosterone

2006
Risk factors in predicting a poor response to sildenafil citrate in elderly men with erectile dysfunction.
    BJU international, 2005, Volume: 95, Issue:3

    To assess the clinical efficacy of sildenafil and the potential predictors of poor response to sildenafil in elderly patients with erectile dysfunction (ED).. The study included 162 patients (aged > or = 60 years) treated with sildenafil for at least 8 weeks; all patients were evaluated with a history, physical examination, measurement of total testosterone and a pharmacological erection test. Sexual function before and 8 weeks after treatment was assessed using the self-administered International Index of Erectile Function (IIEF). Treatment was considered successful when the patient attained a higher grade on the erectile function (EF) domain score, and an affirmative response to the overall assessment question. Factors influencing treatment outcome were evaluated by univariate and multivariate statistical analysis.. The overall efficacy with sildenafil was 47% (76/162). On univariate analysis, uncontrolled diabetes, current smoking, hypogonadism (<3 microg/L testosterone) and low pretreatment EF domain score (<17) were selected as predictors of a poor response. On multivariate logistic regression, a low pretreatment EF domain score was the strongest independent prognostic factor for a poor response (odds ratio 2.25, 95% confidence interval, 1.45-7.33), and this was followed by hypogonadism (1.89, 1.12-3.16) and current smoking (1.34, 1.04-3.52).. In a real clinical setting, sildenafil was effective for about half of the elderly men. The baseline EF domain score, hypogonadism and current smoking were significantly associated with failure of sildenafil. These results suggest that modifying reversible risk factors, e.g. stopping smoking and replacing testosterone, would be beneficial in augmenting the efficacy of sildenafil in elderly men.

    Topics: Aged; Analysis of Variance; Diabetes Complications; Erectile Dysfunction; Humans; Hypogonadism; Male; Middle Aged; Phosphodiesterase Inhibitors; Piperazines; Purines; Risk Factors; Sildenafil Citrate; Smoking; Sulfones; Treatment Failure

2005
Androgens regulate phosphodiesterase type 5 expression and functional activity in corpora cavernosa.
    Endocrinology, 2004, Volume: 145, Issue:5

    By real-time RT-PCR and Western blot analysis, we found that phosphodiesterase type 5 (PDE5) mRNA and protein abundance was several fold higher in human male than in female reproductive tracts. The highest mRNA level (>1 x 10(7) molecules/microg total RNA) was detected in human corpora cavernosa (CC), where PDE5 protein was immunolocalized in both muscular and endothelial compartment. The possible role of androgens in regulating PDE5 expression was studied using a previously established rabbit model of hypogonadotropic hypogonadism. In this model, hypogonadism reduced, and testosterone (T) supplementation restored, CC PDE5 gene and protein expression. In addition, T supplementation completely rescued and even enhanced cyclic GMP conversion to metabolites, without changing IC(50) for sildenafil (IC(50) = 2.16 +/- 0.62 nm). In control CC strips, sildenafil dose-dependently increased relaxation induced by electrical field stimulation, with EC(50) = 3.42 +/- 1.7 nm. Hypogonadism reduced, and T increased, sildenafil effect on electrical field stimulation, again without changing their relative EC(50) values. CC sensitivity to the NO-donor NCX4040 was greater in hypogonadal rabbit strips than in control or T-treated counterparts. Moreover, sildenafil enhanced NCX4040 effect in eugonadal rabbit strips but not in hypogonadal ones. This suggests that androgens up-regulate PDE5 in rabbit penis. We also measured PDE5 gene expression and metabolic activity in human CC from male-to-female transsexual individuals, chronically treated with estrogens and cyproterone acetate. Comparing the observed values vs. eugonadal controls, PDE5 mRNA, protein, and functional activity were significantly reduced. In conclusion, we demonstrated, for the first time, that androgens positively regulate PDE5, thus providing a possible explanation about the highest abundance of this enzyme in male genital tract.

    Topics: 3',5'-Cyclic-GMP Phosphodiesterases; Androgens; Animals; Antibody Specificity; Blotting, Western; Cyclic Nucleotide Phosphodiesterases, Type 5; Epididymis; Female; Gene Expression Regulation, Enzymologic; Humans; Hypogonadism; Immunohistochemistry; Male; Penis; Phosphoric Diester Hydrolases; Piperazines; Prostate; Purines; Rabbits; Reverse Transcriptase Polymerase Chain Reaction; RNA, Messenger; Sildenafil Citrate; Sulfones; Testis; Testosterone; Vas Deferens

2004
A 66-year-old man with sexual dysfunction.
    JAMA, 2004, Jun-23, Volume: 291, Issue:24

    Topics: Aged; Biopsy; Erectile Dysfunction; Hormone Replacement Therapy; Humans; Hypogonadism; Male; Phosphodiesterase Inhibitors; Piperazines; Prostate; Prostatic Neoplasms; Purines; Risk; Sildenafil Citrate; Sulfones; Testosterone

2004
Sildenafil for diabetic men with erectile dysfunction.
    JAMA, 1999, Sep-08, Volume: 282, Issue:10

    Topics: Diabetes Complications; Erectile Dysfunction; Humans; Hypogonadism; Male; Phosphodiesterase Inhibitors; Piperazines; Purines; Sildenafil Citrate; Sulfones

1999