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INTRODUCTION: Naturalistic clinical trials provide data on the effectiveness of drugs in nonexperimental and everyday situations and are extremely helpful for decision-making purposes and for confirming experimental findings in clinical trials. No data have been published from naturalistic studies performed in patients with lower urinary tract symptoms suggestive of benign prostatic hyperplasia (LUTS/BPH) with or without erectile dysfunction (ED) and treated with phosphodiesterase type 5 inhibitors. AIM: The aim of this study (TadaLutsEd Study) was to assess, in the context of medical practice, the effectiveness of tadalafil 5 mg once daily in patients with LUTS/BPH with or without erectile dysfunction. METHODS: The study was a 6-week uncontrolled, prospective, open-label, multicentric, observational study. The patient population involved sexually active males aged ≥ 50 years, diagnosed with LUTS/BPH with or without concomitant ED, and treated with tadalafil 5 mg daily in accordance with standard urological practice. MAIN OUTCOME MEASURES: Effectiveness was assessed through the self-administered International Prostate Symptom Score (IPSS) questionnaire; quality of life was evaluated through the IPSS quality of life section (IPSS-QoL). The patients were also evaluated with the International Index of Erectile Function (IIEF-5). Adverse events were recorded. Statistical analyses using paired data samples was applied (Wilcoxon signed-ranks test). RESULTS: Sixty-two patients (mean age 62.2 years) completed the treatment, of whom 85.5% showed improvement in their urinary symptoms. Pre- and post-treatment differences in the IPSS, IPSS-QoL, and IIEF-5 scores were statistically significant at 4.4, 1, and 5.4 points, respectively (P < 0.0001). Tadalafil was well tolerated, and adverse events were mild, with a discontinuation rate of 1.6%. CONCLUSION: According to study results, the use of tadalafil 5 mg once daily in a nonselected patient population with LUTS/BPH with or without ED led to improvements in terms of symptoms and quality of life and exhibited a safety profile similar to that obtained in controlled tadalafil clinical trials.
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Carbolinas/administração & dosagem , Disfunção Erétil/tratamento farmacológico , Sintomas do Trato Urinário Inferior/tratamento farmacológico , Inibidores da Fosfodiesterase 5/administração & dosagem , Hiperplasia Prostática/tratamento farmacológico , Idoso , Idoso de 80 Anos ou mais , Método Duplo-Cego , Esquema de Medicação , Disfunção Erétil/etiologia , Humanos , Sintomas do Trato Urinário Inferior/complicações , Masculino , Pessoa de Meia-Idade , Estudos Prospectivos , Hiperplasia Prostática/complicações , Inquéritos e Questionários , Tadalafila , Resultado do TratamentoRESUMO
PURPOSE: Medical treatment for men with lower urinary tract symptoms and prostatic enlargement secondary to benign prostatic hyperplasia is 5α-reductase inhibitor monotherapy or coadministration with an α-blocker. We assessed the effects of tadalafil 5 mg coadministered with finasteride 5 mg during 26 weeks on lower urinary tract symptoms and sexual symptoms. MATERIALS AND METHODS: In an international, randomized, double-blind, parallel study of men 45 years old or older who were 5α-reductase inhibitor naïve and had an I-PSS (International Prostate Symptom Score) of 13 or greater and prostate volume 30 ml or greater, 350 were treated with placebo/finasteride and 345 received tadalafil/finasteride for 26 weeks. Changes in lower urinary tract symptoms secondary to benign prostatic hyperplasia were assessed with the I-PSS, erectile dysfunction improvements were assessed with the IIEF-EF (International Index of Erectile Function-Erectile Function) in sexually active men and safety was assessed by evaluating adverse events. RESULTS: Least squares mean changes from baseline in I-PSS after 4, 12 and 26 weeks of tadalafil/finasteride coadministration were -4.0, -5.2 and -5.5, respectively. Corresponding values for placebo/finasteride coadministration were -2.3, -3.8 and -4.5 (p ≤ 0.022 at all visits favoring tadalafil/finasteride coadministration). I-PSS subscores (storage and voiding) and quality of life index were also numerically improved with tadalafil/finasteride coadministration. Least squares mean changes from baseline in IIEF-EF with tadalafil/finasteride coadministration were 3.7 after 4 weeks, and 4.7 after 12 and 26 weeks. Corresponding values for placebo/finasteride coadministration were -1.1, 0.6 and -0.0 (p <0.001 at all visits favoring tadalafil/finasteride coadministration). Tadalafil/finasteride coadministration was well tolerated and most adverse events were mild/moderate. CONCLUSIONS: The coadministration of tadalafil/finasteride provides early improvement in lower urinary tract symptoms in men with benign prostatic hyperplasia and prostatic enlargement. Tadalafil/finasteride coadministration also improves erectile function in men who have comorbid erectile dysfunction.
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Carbolinas/uso terapêutico , Finasterida/uso terapêutico , Sintomas do Trato Urinário Inferior/tratamento farmacológico , Hiperplasia Prostática/tratamento farmacológico , Agentes Urológicos/uso terapêutico , Idoso , Idoso de 80 Anos ou mais , Carbolinas/administração & dosagem , Método Duplo-Cego , Quimioterapia Combinada , Finasterida/administração & dosagem , Humanos , Masculino , Pessoa de Meia-Idade , Tadalafila , Resultado do TratamentoRESUMO
UNLABELLED: Erectile dysfunction (ED) and lower urinary tract symptoms (LUTS) due to benign prostatic hyperplasia (BPH) are often associated, and they both reduce the quality of life of those who suffer from these conditions. OBJECTIVES: Primarily, to determine the relationship of LUTS/BPH as an independent risk factor for suffering ED and, secondarily, the relationship of LUTS/BPH and ED according to the severity of the symptoms. METHODS: A descriptive, analytic, multicentre study was carried out in 580 patients consulting for prostatic control or LUTS. 305 patients, who met the inclusion/exclusion criteria, were included in the analysis. Erectile dysfunction and LUTS were assessed by IIEF5 and IPSS. The presence, predictors and degree of severity of ED were examined according to patients' age and comorbidities. Qualitative and continuous variables were considered for the statistical analysis and simple and multiple regression analyses were applied. A value of p < 0.05 was considered statistically significant. RESULTS: Mean age was 62 years (IQR 56-67) ED prevalence in patients with LUTS/BPH was 83.6%. Patients with ED were older, showed a higher prevalence of hypertension and higher IPSS scores (p < 0.05). Multivariate analysis for ED predictors showed that age, diabetes and IPSS score were significantly associated with ED (p < 0.05). CONCLUSIONS. According to our results, there is a high prevalence of ED in patients with LUTS/BPH, which are also independent risk factors for suffering ED. The presence of ED was more prevalent in moderate LUTS/BPH than in the severe LUTS/BPH. The importance of assessing the sexual health of men consulting for LUTS/BPH is emphasized.
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Disfunção Erétil , Qualidade de Vida , Argentina , Humanos , Sintomas do Trato Urinário Inferior , Hiperplasia Prostática , Encaminhamento e ConsultaRESUMO
BACKGROUND: Tadalafil is being investigated for the treatment of lower urinary tract symptoms (LUTS) suggestive of benign prostatic hyperplasia (BPH-LUTS). OBJECTIVE: To assess efficacy, including onset, and safety of tadalafil on BPH-LUTS and the subject's and clinician's perception of changes in urinary symptoms. DESIGN, SETTING, AND PARTICIPANTS: This randomized, double-blind, placebo-controlled, 12-week trial enrolled men ≥45 yr of age with BPH-LUTS for >6 mo, International Prostate Symptom Score (IPSS) ≥13, and maximum urine flow rate (Q(max)) ≥4 to ≤15 ml/s. INTERVENTION: Tadalafil 5mg (n=161) or placebo (n=164), once daily. MEASUREMENTS: Analysis of covariance (ANCOVA) modeling evaluated change from baseline in continuous efficacy variables. Categoric efficacy variables were analyzed with the Cochran-Mantel-Haenszel test, and between-group differences in treatment-emergent adverse events (TEAEs) were assessed using the Fisher exact test. RESULTS AND LIMITATION: Tadalafil significantly improved IPSS results, from baseline to endpoint, compared to placebo (-5.6 vs -3.6; p=0.004). Reduction in IPSS results was apparent after 1 wk and significant after 4 wk (tadalafil -5.3 vs placebo -3.5; p=0.003). The BPH Impact Index (BII) was not assessed at week 1; however, BII improvement was apparent at 4 wk (tadalafil -1.8 vs placebo -1.2; p=0.029) and continued at 12 wk (tadalafil -1.8 vs placebo -1.3; p=0.057). Tadalafil significantly improved the International Index of Erectile Function-Erectile Function score in sexually active men with erectile dysfunction (ED; 6.7 vs 2.0; p<0.001) at 12 wk (not assessed at week 1). Few subjects reported one TEAE or more (p=0.44). For tadalafil, the most common TEAEs were headache (3.7%) and back pain (3.1%). Tadalafil did not significantly improve Q(max) or reduce postvoid residual volume. CONCLUSIONS: Tadalafil 5mg once daily for 12 wk resulted in a clinically meaningful reduction in total IPSS results as early as 1 wk and achieved statistical significance at 4 wk in men with BPH-LUTS. The adverse event profile was consistent with that previously reported in men with ED. TRIAL REGISTRATION: This clinical trial is registered on the clinicaltrials.gov website (http://www.clinicaltrials.gov). The registration number is NCT00827242.
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Carbolinas/administração & dosagem , Sintomas do Trato Urinário Inferior/tratamento farmacológico , Inibidores da Fosfodiesterase 5/administração & dosagem , Hiperplasia Prostática/tratamento farmacológico , Idoso , Análise de Variância , Argentina , Carbolinas/efeitos adversos , Método Duplo-Cego , Esquema de Medicação , Europa (Continente) , Humanos , Sintomas do Trato Urinário Inferior/etiologia , Sintomas do Trato Urinário Inferior/fisiopatologia , Masculino , México , Pessoa de Meia-Idade , Ereção Peniana/efeitos dos fármacos , Inibidores da Fosfodiesterase 5/efeitos adversos , Placebos , Hiperplasia Prostática/complicações , Hiperplasia Prostática/fisiopatologia , Tadalafila , Fatores de Tempo , Resultado do Tratamento , Estados Unidos , Micção/efeitos dos fármacos , Urodinâmica/efeitos dos fármacosRESUMO
INTRODUCTION: Peyronie's disease (PD) is a localized fibrosis that affects the tunica albuginea of the penis. Its origin can be associated with coital penile trauma in men with autoimmune hypersensitivity and a presumed genetic predisposition. AIM: To identify clinical and traumatic risk factors in a patient population with PD, when compared to a control group. METHODS: From November 2007 to March 2010, 317 patients sought medical attention for PD. As control group, 147 consecutive patients, who came for a prostate exam, were studied. Clinical, traumatic, and sexual history of these patients was gathered. Risks factors were considered only if they had been present before the onset of PD symptoms. MAIN OUTCOME MEASURE: The International Index of Erectile Function and the International Prostate Symptoms Score. A univariate logistic regression model (chi-square) (odds ratios [ORs] and 95% confidence intervals [CI]) was used to estimate the association of risk factors with PD; and the Student's t-test was implemented for age. RESULTS: The mean age of patients with PD and control group was 56.7 and 58.8, respectively (P<0.923). The mean evolution time of the disease was 17.7 months (2-48). Erectile dysfunction (ED) and coital trauma constituted the only two independent risk factors for PD compared to the control group (P<0.05 and 0.002, respectively) with an OR of 1.5 (95% CI 1.0-2.3) and 2.69 (95% CI 1.41-5.21), respectively. Patients with ED and diabetes mellitus and with a mild-to-moderate ED also presented a higher predisposition (P=0.008 and 0.00001), with an OR of 3.64 (95% CI 1.33-10.79) and 5.58 (95% CI 3.03-10.42), respectively. CONCLUSION: Erectile dysfunction and coital trauma have proven to be independent risk factors for the development of PD.
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Induração Peniana/etiologia , Adulto , Idoso , Idoso de 80 Anos ou mais , Estudos de Casos e Controles , Coito/fisiologia , Complicações do Diabetes/patologia , Complicações do Diabetes/fisiopatologia , Disfunção Erétil/patologia , Disfunção Erétil/fisiopatologia , Humanos , Modelos Logísticos , Masculino , Pessoa de Meia-Idade , Ereção Peniana/fisiologia , Induração Peniana/patologia , Induração Peniana/fisiopatologia , Pênis/patologia , Pênis/fisiopatologia , Próstata/patologia , Próstata/fisiopatologia , Fatores de Risco , Comportamento SexualRESUMO
INTRODUCTION: In recent years, PDE5 inhibitors (PDE5i) use has become more popular among men without ED to enhance sexual performance. However, reports in the literature are scarce. AIM: The aim of this study was to evaluate the recreational use of PDE5i in healthy young men. MAIN OUTCOME MEASURES: We evaluated the recreational use of PDE5i among young and healthy men, their main reasons for use, how they were obtained these drugs, and the combination with alcohol or other drugs. METHODS: Descriptive, transversal study consisting in 400 brief surveys with structured multiple choice and open questions. Nonprobability samples (quota samples) included young men between 18 and 30 years of age in a public area (high schools, universities, and gyms) between August and November 2009. Collecting the questionnaires in a sealed box enforced confidentiality. The survey included demographic and sexual health data and PDE5i use characteristics. For statistical analysis we used Fisher's exact and Mann-Whitney tests. RESULTS: A total of 321 questionnaires were appropriate for the purposes of evaluation. Mean age and standard deviation were 25.1±3.3 years old. Regarding PDE5i use, 69 men (21.5%) mentioned trying the pill (being sildenafil the most commonly used one) at least one time in their lives and 37 (53.4%) men combined it with alcohol or drugs. Referred sources of acquisition PDE5i were 75.4% (N=52) from a friend, 17.4% (N=15) from a pharmacy/drugstore without a medical prescription, 4.3% (N=3) prescribed by a physician and 2.9% (N=2) through Internet. There were several reasons for taking PDE5i related to sexual confidence, erection quality, and better sexual performance. CONCLUSION: According to our results, 21.5% of healthy men between 18 and 30 years old used PDE5i as a recreational drug, mostly associated with alcohol or other drugs without medical control. This could have led to misuse and a public health problem. Further studies are needed to evaluate not only PDE5i recreational use prevalence, but also psychosocial determinants, long term safety, misuse, and abuse related to it.
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Preservativos/estatística & dados numéricos , Disfunção Erétil/tratamento farmacológico , Inibidores da Fosfodiesterase 5/uso terapêutico , Assunção de Riscos , Transtornos Relacionados ao Uso de Substâncias , Adolescente , Adulto , Fatores Etários , Comportamentos Relacionados com a Saúde , Indicadores Básicos de Saúde , Inquéritos Epidemiológicos , Humanos , Masculino , Inquéritos e Questionários , Adulto JovemRESUMO
INTRODUCTION: The high incidence of erectile dysfunction (ED) and lower urinary tract symptoms (LUTS) in aging men and the same pathophysiology make probable to treat both disorders with the same treatment. Numerous authors evaluated the actions of PDE5i in improving the LUTS/(benign prostate hyperplasia) BPH. AIM: To assess the efficacy and safety of tamsulosin 0.4 mg/day vs. tamsulosin 0.4 mg/day plus tadalafil 20 mg/day in patients with LUTS in a crossover design study. MAIN OUTCOMES MEASURES: International Prostate Symptoms Score (IPSS), IPSS Quality of Life (IPSS-QOL), maximum flow rate (Qmax), post-void residual volume (PVR), International Index of Erectile Function-Erectile Function Domain (IIEF-EF), Global Assessment Quality (GAQ). For the statistical analysis, a Tukey-Kramer multicomparison test was used. METHODS: A randomized, double-blind, crossover study was conducted from September 2007 to February 2008 in one center. Thirty men, older than 50 years old, with a history of LUTS/BPH of at least 6 months, were randomized into two groups to receive tamsulosin 0.4 mg/day vs. tamsulosin 0.4 mg/day plus tadalafil 20 mg/day for 45 days, and then switched to the other treatment mode for other 45 days. RESULTS: Twenty-seven patients completed the study. Improvements of IPSS score and IPSS-QOL were significant with both treatments but greater with the drug combination. Both regimens similarly improved the Qmax and decreased the PVR volume from baseline (P < 0.001) with no significant differences between tamsulosin alone vs. tamsulosin and tadalafil (P > 0.05). The IIEF improved with tamsulosin plus tadalafil (P < 0.001) but not with tamsulosin alone (P > 0.05). The GAQ showed that all patients preferred the combination scheme. Both treatments were well tolerated. CONCLUSION; Tamsulosin 0.4 mg/day plus tadalafil 20 mg/day was more effective than tamsulosin 0.4 mg/day alone to improve LUTS and erectile dysfunction and was also well tolerated. Large-scale, randomized, placebo-controlled studies are needed to further assess the long-term safety and effectiveness of these agents in treating LUTS/BPH with or without ED.
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Carbolinas/administração & dosagem , Disfunção Erétil/tratamento farmacológico , Inibidores de Fosfodiesterase/administração & dosagem , Hiperplasia Prostática/tratamento farmacológico , Sulfonamidas/administração & dosagem , Obstrução do Colo da Bexiga Urinária/tratamento farmacológico , Retenção Urinária/tratamento farmacológico , Idoso , Carbolinas/efeitos adversos , Estudos Cross-Over , Método Duplo-Cego , Quimioterapia Combinada , Humanos , Masculino , Pessoa de Meia-Idade , Inibidores da Fosfodiesterase 5 , Qualidade de Vida , Sulfonamidas/efeitos adversos , Tadalafila , Tansulosina , Resultado do TratamentoRESUMO
INTRODUCTION: Available information on the efficacy and safety of tadalafil on Latin American men comes from reports where data is mixed with other populations. AIM: To assess the efficacy and safety of tadalafil in Latin American men with erectile dysfunction (ED). METHODS: Integrated analyses of data from four 12-week, randomized, double-blind, parallel, placebo-controlled trials conducted in Latin America that assessed the efficacy and safety of tadalafil in 406 Latin American men with ED of diverse etiology and severity assigned to placebo (N = 113), 10-mg tadalafil (N = 39), or 20-mg tadalafil (N = 254). MAIN OUTCOME MEASURES: Efficacy was assessed by International Index of Erectile Function Erectile Function (IIEF-EF) domain, questions 2 to 5 of the Sexual Encounter Profile and the first Global Assessment Question. Adverse events (AEs) reported by all enrolled patients were collected. RESULTS: Latin American patients treated with 10 or 20 mg of tadalafil had a significant mean improvement of 4.92 and 9.78, respectively, in the IIEF-EF domain score from baseline compared with 2.24 on placebo (P = 0.003 and P < 0.001, respectively, vs. placebo). At both doses, the mean success rate for penetration was 75 and 86%, respectively, compared with 56% on placebo (P < or = 0.001), the mean success rate for intercourse was 55% and 78%, compared with 36% on placebo (P < 0.001 vs. placebo), and 62% and 91% of patients, respectively, reported improved erections at the end point, vs. 43% on placebo (P = 0.160 and P < 0.001, respectively, vs. placebo). The most frequent AEs were headache, dyspepsia, and back pain. CONCLUSIONS: 10 or 20 mg tadalafil was an effective, safe, and well-tolerated therapy for Latin American men with ED of diverse etiology despite of ED severity.
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Carbolinas/uso terapêutico , Disfunção Erétil/tratamento farmacológico , Inibidores de Fosfodiesterase/uso terapêutico , Adulto , Idoso , Carbolinas/efeitos adversos , Relação Dose-Resposta a Droga , Método Duplo-Cego , Disfunção Erétil/psicologia , Humanos , América Latina , Masculino , Pessoa de Meia-Idade , Satisfação do Paciente , Ereção Peniana/efeitos dos fármacos , Inquéritos e Questionários , Tadalafila , Resultado do TratamentoRESUMO
INTRODUCTION AND AIM: This study evaluated the possible differences between an angiotensin converting enzyme (ACE) inhibitor and a beta-blocker concerning their potential protective role on female external genitalia in spontaneously hypertensive rats (SHR). MAIN OUTCOME MEASURES: Morphological changes in the clitoris after antihypertensive treatments. METHODS: For 6 months, SHR received no treatment; SHR + ramipril (RAM), SHR + atenolol (AT), and control Wistar Kyoto (WKY) rats received no treatment. Clitorises were processed for immunohistochemistry using anti-alpha-smooth muscle actin (alpha-SMA), anti-collagen I and III, anti-transforming growth factor beta(1) (TGFbeta(1)), and anti-endothelial nitric oxide synthase (eNOS) antibodies. RESULTS: SHR + RAM and SHR + AT presented significantly lower blood pressure in both groups vs. untreated SHR. Compared with WKY, alpha-SMA was increased in the arteries and in the cavernous spaces of the clitoris together with a marked increase in wall/lumen ratio in clitoral vessels in untreated SHR. All these alterations were diminished in SHR + AT (P < 0.01). SHR + RAM presented differences with respect to SHR + AT in the reduction of these variables. TGFbeta(1) expression in the vessel wall from the clitoris and collagen I and III deposition in the interstitium from the clitoris in untreated SHR were significantly more (P < 0.01) than in WKY. While SHR + AT showed a mild decrease in these variables, SHR + RAM presented a significant reduction (P < 0.01) in TGFbeta(1) expression interstitial fibrosis and in both types of collagens. Positive immunostaining of eNOS in the sinusoidal endothelium from the clitoris was less (P < 0.01) in untreated SHR (3.4 +/- 1.3%) and SHR + AT (5.1 +/- 1.2%) than in SHR + RAM (17.2 +/- 1.6%) and WKY (15.9 +/- 1.7%). Untreated SHR and SHR + AT presented more surrounding connective tissue at the perineurium in the clitoris (P < 0.01) than SHR + RAM. CONCLUSION: ACE inhibition provided a considerable protective role on the female external genitalia structures in SHR by a mechanism that may be, at least in part, independent of the degree of blood pressure lowering.
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Antagonistas Adrenérgicos beta/farmacologia , Inibidores da Enzima Conversora de Angiotensina/farmacologia , Clitóris/efeitos dos fármacos , Hipertensão/tratamento farmacológico , Antagonistas Adrenérgicos beta/administração & dosagem , Inibidores da Enzima Conversora de Angiotensina/administração & dosagem , Animais , Colágeno/metabolismo , Modelos Animais de Doenças , Relação Dose-Resposta a Droga , Feminino , Imuno-Histoquímica/métodos , Ratos , Ratos Endogâmicos WKYRESUMO
INTRODUCTION: Female sexual dysfunction and its therapeutic approach is a growing area. AIM: We aimed to assess the subjective and objective changes of the female sexual response, in patients with orgasmic sexual dysfunction using 3 mg SL Apomorphine (APO). METHODS: Twenty-four patients (mean age 32 years old, SD: 9.69) were included in a prospective randomized cross-over protocol. Sexual response was evaluated objectively (duplex ultrasound) and subjectively (self-reported questionnaire) following vibrator stimuli with the addition of 3 mg SL APO or placebo. MAIN OUTCOME MEASURE: Sexual response objective (PSV, EDV, RI) and subjective (arousal and lubrication degree and orgasm achievement). Adverse events were also recorded. RESULTS: Clitoral hemodynamical changes, particularly peak systolic velocity (PSV), were significantly higher with APO (P = 0.003), mean increase of PSV poststimulus was 72.50% with placebo (from 9.7 cm/second to 17.0 cm/second) and 139.14% with APO (from 9.7 cm/second to 21.4 cm/second). SUBJECTIVE CHANGES (AROUSAL AND LUBRICATION) WERE ALSO SIGNIFICATIVE WITH APO (P < 0.05). CONCLUSION: According to our observations, APO seemed to produce more subjective and objective changes in the sexual arousal phase of women with orgasmic sexual dysfunction than placebo. Future research is needed to evaluate the place of this drug in the treatment of the female sexual dysfunction.
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Apomorfina/uso terapêutico , Comportamento Sexual/efeitos dos fármacos , Disfunções Sexuais Fisiológicas/tratamento farmacológico , Administração Sublingual , Adulto , Apomorfina/administração & dosagem , Estudos Cross-Over , Agonistas de Dopamina/administração & dosagem , Agonistas de Dopamina/uso terapêutico , Feminino , Humanos , Orgasmo/efeitos dos fármacos , Placebos , Estudos Prospectivos , Resultado do TratamentoRESUMO
OBJECTIVE: The present study reviews the mechanism involved in the initiation and maintenance of penile erection. METHOD: The study reviews the literature on the basic concepts supporting either "magically" or scientifically the erectile mechanism. An anatomo-physiological update is also included (i.e., the main neurological, muscular, and vasculoendothelial phenomena). RESULTS: Present studies based on the vasoactive action of different drugs have increased the knowledge on the neurological, muscular, and vasculoendothelial phenomena. The cavernous muscular relaxation may start and finish due to the equilibrium between the contractile adrenergic and the relaxing non adrenergic-non cholinergic stimulus through intracellular nitric oxide synthesis. This is an essential phenomenon involved in the entry and "trapping" of blood within the sinus spaces. CONCLUSIONS: Our knowledge on the erectile mechanisms through neuromediators is increasing. The role of the endothelium in intracellular nitric oxide synthesis and its relaxing effect, will improve our understanding of both physiological and therapeutic phenomena.