SEARCH · PubMed Health

Results for “Erectile Dysfunction”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 343 records · Page 19Linked to original sources

PubMedDate not supplied

[Erectile dysfunction after radial prostatectomy. Response to treatment with sildenafil citrate].

OBJECTIVES: Erectile dysfunction is one of the sequelae after radical prostatectomy most concerning for the patient, its appearance being influenced by factors such as surgical technique, or patient's age. Thus, around 40% of the patients younger than 70 years and over 90% of the patients older than 70 present with erectile dysfunction after prostatectomy. We studied the response to sildenafil citrate in patients who underwent non nerve sparing radical prostatectomy. METHODS: Medical records of 100 patients who underwent radical prostatectomy at our department between 1985 and 1998 were retrospectively reviewed and telephone interviews were done to investigate the degree of erectile dysfunction following surgery. All patients were offered to start a two-month therapeutic trial with sildenafil citrate, in dose escalation up to a maximum of 100 mg. Therapeutic response was evaluated by personal interviews. RESULTS: 5 out of 100 patients interviewed showed similar potency than preoperatively. Among 95 patients with erectile dysfunction 63 (66.3%) did not wish treatment for erectile dysfunction. 22 of the remainder 32 patients initiated treatment with sildenafil citrate, whereas 10 preferred trying intracavernous PGE1 injections only. In the intracavernous injections group 5 patients abandoned because of pain with injections and refused any further treatment with oral drugs; 5 patients are satisfied with intracavernous therapy and they do not want to try sildenafil. In the sildenafil group form 22 patients starting treatment 14 (63.6%) are satisfied, with a subjective improvement. Only 5 patients (22%) show an erectile response enough to have sexual intercourse with penetration. 8 (36.5%) abandon treatment because of lack of efficiency. CONCLUSIONS: 5% of the patients who undergo non nerve sparing radical prostatectomy maintain sexual potency without treatment postoperatively. Most patients with postoperative erectile dysfunction (63/95 = 66.3%) do not want any treatment. From 22 patients initiating treatment with sildenafil 5 can have sexual intercourse with penetration (5/22 = 22%), all of them with 100 mg doses of sildenafil.

Aged↗

PubMed2005

[Erectile dysfunction drugs and women].

Erectile dysfunction (ED) is no more a taboo and the number of patients who are consulting a physician and asking for some help in this domain is growing every day. The quality of life of men presenting an ED and having access to treatments is continually improving. But what can be said concerning the partners' quality of life? Patients as much their partners clearly prefer lesser invasive therapeutics and the new oral drugs available present some advantages for the couples, and surely for a majority of female partners, willing to improve the spontaneity and the frequency of intercourse. It seems now obvious that the partner's help is one of the key points for a successful treatment. How will women facing this recovered virility react? What will they say in the secret of the consulting room? What could be exactly the role of the gynaecologist in assuming the female partner of a man treated for an ED? That is the object of the present article, dealing with quite an important matter.

Attitude↗

PubMed2002

A shared care approach to the management of erectile dysfunction in the community.

Erectile dysfunction (ED) affects men of all ages and results in considerable distress and impact on quality of life for those who suffer from it. As ED is associated with a wide variety of under-lying conditions and cardiovascular co-morbidities, there is a requirement for diversity of treatment options and several factors must be considered to customise and optimise therapy. In the ideal holistic approach to management of the ED patient, both primary care and specialist physicians have an important role to play. This article reports on a sequential approach for the diagnosis and treatment of ED, with an emphasis on 'shared care'. The deliberations are based on a pan-European inter-disciplinary group that met at the Lygon Arms, UK on 22 February 2002.

Erectile Dysfunction↗

PubMed2006

Ocular safety in patients using sildenafil citrate therapy for erectile dysfunction.

Sildenafil citrate improves erectile function in men with erectile dysfunction (ED) by selectively inhibiting cyclic guanosine monophosphate (cGMP)-specific phosphodiesterase type 5 (PDE5), which is present in all vascular tissue. Sildenafil also has a weaker inhibitory action on PDE6, located in the rod and cone photoreceptors. Modest, transient visual symptoms, typically blue tinge to vision, increased brightness of lights, and blurry vision, have been reported with sildenafil use and occur more frequently at higher doses. Visual function studies in healthy subjects and in patients with eye disease suggest that sildenafil does not affect visual acuity, visual fields, and contrast sensitivity. Transient, mild impairment of color discrimination can occur around the time of peak plasma levels. Spontaneous postmarketing reports of visual adverse events, including nonarteritic anterior ischemic optic neuropathy (NAION), have been reported during the 7 years that sildenafil has been prescribed to more than 27 million men worldwide. However, because men with ED frequently have vascular risk factors that may also put them at increased risk for NAION, a causal relationship is difficult to establish. No consistent pattern has emerged to suggest any long-term effect of sildenafil on the retina or other structures of the eye or on the ocular circulation.

Color Vision Defects↗

PubMed2002

Potassium channels and erectile dysfunction.

The incidence of erectile dysfunction (ED), defined as the persistent inability to achieve or maintain an erection sufficient for satisfactory sexual performance, increases with age and with risk factors for vascular disease, including smoking, diabetes and hypertension. Penile erection results from an arousal-induced synthesis of nitric oxide (NO) in nonadrenergic-noncholinergic nerves (NANC), endothelial cells and cavernosal smooth muscle cells (SMCs). Vasodilation and relaxation of cavernosal SMCs engorges the corpora cavernosa with blood at arterial pressure. The subcellular mechanism by which tumescence occurs involves NO-induced activation of soluble guanylate cyclase, increased cyclic guanosine monophosphate (cGMP) levels and activation of cGMP-dependent protein kinase (PKG). PKG phosphorylates numerous ion channels and pumps, each promoting a reduction in cytosolic calcium. In particular, PKG activates high-conductance Ca2+(-)sensitive K+ (BKCa) channels, which hyperpolarize the arterial and cavernosal SMC membranes, causing relaxation. This mechanism appears to be compromised with age and with vascular disease, leading to ED. Thus, increasing cavernosal nitric oxide synthase (NOS) expression, cGMP levels and/or BKCa channel expression is an effective therapy for experimental ED. Future therapies may involve augmenting K+ channel expression by gene transfer or increasing channel function through the use of Type 5 phosphodiesterase (Type 5 PDE) inhibitors or phosphatase inhibitors.

Aging↗

PubMed2001

Analysis of NOS isoform changes in a post radical prostatectomy model of erectile dysfunction.

Optimal treatment of erectile dysfunction (ED) following radical prostatectomy remains a subject of much controversy and is a significant concern for prostate cancer patients requiring surgical intervention. Neural stimulation involving nitric oxide synthase (NOS) is a crucial aspect of the normal erection process. In this study NOS isoform interaction was evaluated to improve our understanding of molecular changes pertaining to erection post radical prostatectomy. Bilateral cavernous nerve (CN) resected and control adult male Sprague-Dawley rats were killed 7, 14 and 21 days after injury. RT-PCR, in situ hybridization, Western blot and immunohistochemical analysis were used to evaluate changes in NOS isoform expression and distribution. NOS-I protein was dramatically decreased after CN injury while NOS-III and NOS-II remained unchanged. A profound decrease in smooth muscle and endothelium was observed in the corpora. To our knowledge this is the first report of differential altered NOS isoform protein abundance under conditions which mimic radical prostatectomy. These results show the importance of maintaining at least partial innervation of the penis after surgical intervention and that endothelial and smooth muscle changes resulting from loss of innervation may account for the ED observed in prostatectomy patients.

Actins↗

PubMed2003

Hypertension, anti-hypertensive drug therapy and erectile dysfunction in diabetes.

AIMS: Erectile dysfunction (ED) is common in diabetes and may be related to the high prevalence of hypertension and consequent anti-hypertensive drug therapy in diabetic patients. The risk factors for ED were studied with particular reference to hypertension and anti-hypertensive drugs. METHODS: We performed a retrospective case note analysis of 763 consecutive male patients (34% Type 1 diabetes, 65% Type 2 diabetes) attending an adult diabetic clinic to collect data on risk factors for ED. We specifically recorded the use of anti-hypertensive drugs. RESULTS: Two hundred and ninety-nine (39%) patients had ED. Mean age of patients with ED (61 years) was higher than those without (mean age 51 years, P < 0.001). The mean age of hypertensive patients was also significantly higher than those without. On multivariate regression analysis, age (P < 0.001), macrovascular disease (P < 0.001), sensorimotor neuropathy (P < 0.001) and HbA1c (P < 0.05) predicted ED. Neither hypertension nor any anti-hypertensive medication independently predicted ED. CONCLUSION: Our data suggest that ED in diabetic patients with hypertension may be related to the higher age and prevalence of macrovascular disease rather than hypertension or its treatment.

Adolescent↗

PubMed2004

Erectile dysfunction: symptom or disease?

Erectile dysfunction (ED) has been defined by the National Institute of Health (NIH) as the inability to achieve and/or to maintain an erection for a sufficiently long period of time so as to permit satisfactory sexual intercourse. ED affects millions of men throughout the world and could have a negative influence on the individual's well-being as well as on the quality of life of affected subjects. Discordant data have been reported on ED epidemiology with prevalence ranging from 12% to 52%, probably depending on the different criteria utilized in the different studies for patient selection. ED is a symptom, sometimes the first, of different pathological conditions. In 15.7% of 45-yr-old patients with vascular ED a dynamic ergometric test has shown electrocardiographic alterations in the absence of any cardiac symptom. In 15% of the patients with ED, high fasting glucose plasma levels are discovered for the first time and in patients with ED and normal fasting glucose plasma levels the prevalence of undiagnosed diabetes mellitus is 12.1% after an oral glucose tolerance test (OGTT). The different risk factors are often additive in the possible development of systemic vasculopathy, neuropathy and ED. ED, underestimated in clinical practice due to archaic prejudice which hinders the patient in spontaneously revealing the problem and the physicians in investigating it, can mark the point where evaluation and prevention of important diseases (such as diabetes, arterial hypertension, atherosclerosis) hitherto unknown by the patients, can begin. The physicians' cultural baggage must include the ability to identify the pathology that can determine ED and the ability to program a specific diagnostic workup. In this paper the different specialists involved in ED diagnosis agreed that a clinical approach which allows the identification of systemic pathologies contributing to the development of ED constitutes an improvement in disease prognosis and may either induce a spontaneous reduction of ED or facilitate its specific treatment.

Adult↗

PubMed2002

Erectile dysfunction: oral pharmacotherapy options.

Erectile dysfunction (ED) (impotence) is a widespread, age-related problem, which affects 52% of men between 40 and 70 years of age. It is classified as psychogenic, organic, or mixed psychogenic and organic. ED is not a problem only of men, because the relationship between partners can also be disturbed. Therefore, adequate treatment of ED is needed and the most convenient and simplest way is oral drug therapy. Sildenafil, phosphodiesterase-(PDE)-5-selective inhibitor has been the drug of choice for patients with ED since it has been launched in March 1998. The results of various studies have confirmed the efficacy of the drug in men with ED of various etiologies, as well as the positive effect of sildenafil on the quality of a partnership. The most frequent adverse effects documented with sildenafil usage are headache, flushes, dyspepsia, visual disturbances and nasal congestion/rhinitis. These adverse effects are dose-related, usually transient and mild, with low withdrawal rate. Several studies performed recently have shown that sildenafil is a safe and effective treatment of ED in patients with cardiovascular disease, who do not take nitrates or nitrate donors concomitantly. Other oral medications for ED include apomorphine, phentolamine, yohimbine, trazodone, testosterone and new PDE-5 inhibitors in Phase III clinical trials, such as vardenafil and tadalafil. It is obvious, according to recent data, that the concept of PDE-5 inhibition has a central position in oral pharmacotherapy of ED. However, larger clinical studies of efficacy and safety should be carried out using most of the other above-mentioned oral agents and these may also gain a place in the therapy of ED. There are no studies directly comparing sildenafil and other treatments of ED or assessing its role in combination with other therapies. According to the present knowledge, the quality of life, not only of patients but also of their sexual partners, will be improved significantly with sildenafil usage and this is an important precondition for overall health ofboth. Sildenafil is thus a highly effective peroral treatment for ED in patients without contraindications for its use, which can be considered as the firstline therapy with an acceptable risk-benefit ratio.

Administration, Oral↗

PubMed2000

Efficacy, safety and patient acceptance of sildenafil citrate as treatment for erectile dysfunction.

PURPOSE: We assessed the efficacy and safety of sildenafil citrate as treatment for erectile dysfunction. MATERIALS AND METHODS: A total of 433 completely evaluated men with chronic erectile dysfunction were treated with sildenafil citrate. Response was assessed prospectively by baseline and followup physician interviews, and by a patient self-administered 15-item questionnaire on the domains of patient treatment response and satisfaction, partner treatment satisfaction, comparative previous treatment satisfaction, adverse effects, and patient and partner quality of life. RESULTS: Of the 304 men (70.2%) who completed the questionnaire 278 received sildenafil, including 186 who previously had undergone treatment for erectile dysfunction, principally involving intracavernous injection therapy. A response was elicited by a median dose of 100 mg. in 188 patients (67.6%) who achieved erection suitable for sexual intercourse. Those with psychogenic erectile dysfunction responded significantly better than those with organic dysfunction (p <0.001). Erection suitable for intercourse was attained by 30.8% of patients with erectile dysfunction after radical prostatectomy and 80% with cavernous veno-occlusive dysfunction. Of previous intracavernous injection responders 29.9% were refractory to sildenafil, while 33. 3% of previous intracavernous injection nonresponders responded to sildenafil. The sildenafil response was considered inferior to the intracavernous injection response by 43.6% of the men who previously responded to intracavernous injection, of whom 51.5% continued to receive intracavernous injection as the only treatment (19.5%) or as an alternative to sildenafil (32%). Adverse effects in 53.6% of cases were assessed as mild in 56.4%, moderate in 38.3% and severe in 5.3%. Multiple adverse effects were reported by 62.4% of patients, while 17 (6.1%) discontinued sildenafil as a direct result of intolerable adverse effects. The most common adverse effects were facial flushing in 33.5% of cases, headaches in 23.4%, nasal congestion in 12.6%, dyspepsia in 10.1% and dizziness in 10.8%. Baseline patient and partner quality of life scores significantly improved after sildenafil treatment (p <0.001), while significantly improved quality of life was noticed by 51.5% and 43.1%, respectively. CONCLUSIONS: Sildenafil citrate is effective oral first line treatment for erectile dysfunction. Although more than 50% of men reported adverse effects, most were considered mild and rarely resulted in treatment cessation. There was a trend in those on intracavernous injection who responded to sildenafil to continue intracavernous injection as the only therapy or as an alternative to sildenafil. Also, we noted that some cases refractory to sildenafil responded to intracavernous injection. These findings imply that intracavernous injection remains an effective erectile dysfunction treatment option.

Adult↗

PubMed2004

[Erectile dysfunction. Epidemiology, physiology, etiology, diagnosis and therapy].

Erectile dysfunction is a common, age-dependent functional disturbance of men associated to various comorbidities. Interdisciplinary cooperation with neurologists in cases of a suspected neurological aetiology and with psychiatrists in cases with normal organic diagnostic findings is necessary. Hormone replacement and psychotherapy can cure certain patients. Oral pharmacotherapy is the most effective therapy for erectile dysfunction with the highest patient preference. Oral PDE-5-inhibitors (sildenafil, tadalafil, vardenafil) are superior in effectiveness to centrally acting drugs (apomorphin, yohimbine). Local pharmacotherapy (MUSE, ICI) is a second line therapy in cases of failure or contraindications for oral pharmacotherapy. Vacuum therapy and operative procedures (penile implants) complete the therapeutic options of erectile dysfunction.

Erectile Dysfunction↗

PubMed2005

[Erectile dysfunction in the case of cardiovascular disease].

Erectile dysfunction is frequent in those suffering from heart disease. It could be a good marker of an intra-clinical arterial disease. From a therapeutical point of view, intracavernous injections of PGE1 are efficient and safe second line in the treatment of erectile dysfunction in the cardiac population, whatever the origin. No drug interactions with the various treatment used in cardiology, notably derived nitrates, has been reported. Management of erectile dysfunction helps to reinforce patients' adherence to their other treatments.

Alprostadil↗

PubMed1999

Prospective pilot study of sildenafil for treatment of postradiotherapy erectile dysfunction in patients with prostate cancer.

PURPOSE: Erectile dysfunction is a common late complication patients may experience after external-beam radiotherapy for prostate cancer. The efficacy and safety of oral sildenafil to correct sexual dysfunction caused by external-beam radiotherapy was studied in patients participating in our prospective trial. PATIENTS AND METHODS: Thirty-five assessable patients participated in this prospective pilot study. Using a 25-point scale based on the International Index of Sexual Function, erectile dysfunction was assessed weekly, during which time patients received sildenafil 100 mg orally once a week for 6 consecutive weeks. Response was defined as a score of 18 or more, corresponding to at least one successful attempt at sexual intercourse per week. RESULTS: Thirty patients (86%) completed the 6-week study. Seventy-seven percent of these patients had significantly improved erectile function, allowing recovery of full capacity for sexual intercourse. Of 27 patients not receiving concomitant hormone treatment, failure to respond was observed in only four patients (15%) compared with four (50%) of eight patients receiving hormonal treatment during the study. The time course of response was gradual, with 40%, 57%, 66%, 69%, and 74% responding at weeks 1 through 5, respectively. Therapy was generally well tolerated. The most frequently reported side effects in patients were flushing (37%), transient headache (17%), and dyspepsia (9%). No patient reported priapism, and no cardiovascular event or death was observed. After response, 12 patients (34%) reported the ability to achieve and maintain an erection sufficient for intercourse in the absence of sildenafil (ie, 24 hours to 6 days after taking the medication). CONCLUSION: This study suggests that oral sildenafil is well tolerated and can reverse erectile dysfunction after radiotherapy in a substantial proportion of prostate cancer patients.

Adult↗

PubMed1998

Bulbocavernosus reflex studies and autonomic testing in the diagnosis of erectile dysfunction.

The electrophysiologic evaluation of patients with erectile dysfunction presents an important diagnostic challenge. The bulbocavernosus reflex (BCR) latency has been commonly used to evaluate these disorders. However, it is a measure of somatic penile innervation, whereas erection is primarily dependent on autonomic function. We evaluated 195 men with erectile dysfunction over a 3 year period. Each had electrophysiologic studies, nerve conduction studies and a BCR. BCR studies were abnormal in only 7%, of which most had diabetes or pelvic trauma. The BCR was the sole electrophysiologic abnormality in only 2%. Autonomic testing (AT) was additionally performed in 19 diabetic and 23 non-diabetic patients. This included sympathetic skin responses and measurement of the Valsalva ratio and heart rate variability with 6/min breathing. In the diabetic group, AT was positive in 63%, and most often was the sole abnormality. The bulbocavernosus reflex is relatively insensitive in the diagnosis of erectile dysfunction. Brief autonomic testing may provide valuable additional data, particularly in diabetics.

Adult↗

PubMed2000

[Ischemic heart disease in patients with erectile dysfunction].

BACKGROUND: Erection is an hemodynamic event and accordingly, erectile dysfunction is closely related with ischemic heart diseases. Sufficient study has yet to be made of this relation. METHOD: Fifty-eight patients with erectile dysfunction participated in the present study. Intracavernous injection tests and color Doppler examination were conducted for assessment of erectile function. For patients with history of ischemic heart disease, we referred to their doctor for data from their examinations. For patients otherwise, chest X-rays and electrocardiograms in the resting position were obtained and also electrocardiograms following exercise. Echocardiograms, treadmill test results, thallium exercise scintigrams, and coronary angiograms were obtained as requires for diagnosis. RESULTS: Eighteen patients (31.0%) were diagnosed as ischemic heart disease or at high risk. Although 6 of them had been already diagnosed with ischemic heart disease, 12 were newly diagnosed by the exercise tests. Among these 18 patients 16 had one or more significant risk factors for ischemic heart disease such as age, hyperlipidemia, and diabetes mellitus. 3.7% of patients whose peak systolic velocity in the cavernous artery was equal to or exceeded 35 cm/sec had ischemic heart disease or were at high risk. 54.8% of patients with peak systolic velocity of less than 35 cm/sec had ischemic heart disease or were at high risk. CONCLUSIONS: In erectile dysfunctional patients, incidence of complications with symptomatic or asymptomatic ischemic heart disease was found to be high. Therefore, in patients with risk factors or low peak systolic velocity in the cavernous artery, exercise tests should be implemented prior to treatment of erectile dysfunction.

Aged↗

PubMed2004

Erectile dysfunction rates and requests for treatment in patients attending outpatient urology clinics and those accompanying them.

BACKGROUND: Erectile dysfunction is a common sexual function disorder in men. The aim of the present study was to determine the rates of erectile dysfunction and requests for treatment in male patients refered to our outpatient urology clinics and those accompanying them who were older than 20 years. METHODS: The study comprised 2 groups: group 1 included male patients older than 20 years whom attend to the outpatient urology clinics, and group 2 included their companies whom were older than 20 years. Subjects were asked whether they had erectile dysfunction or not, if so whether they had been treated or not, if not then why, and whether they desired treatment or not at present. RESULTS: Erectile dysfunction was determined in 224 subjects (13.9%) in group 1, and 57 (8.5%) in group 2. It was found that approximately one half (49.1%) of patients with erectile dysfunction did not complain about this. The main reasons for this were failure to perceive sexual dysfunction as a problem, and shame. Of 281 men who determined to have erectile dysfunction, 71 indicated that they desired treatment. In those who did not desire treatment, the main reasons were failure to perceive it as a problem, and shame. CONCLUSIONS: These findings show that the doctor has a great responsibility in determining erectile dysfunction. Therefore discussions of sexual health should be made a routine part of doctor-patient discussions, and patients, especially those over 50, should be asked whether they have a complaint of erectile dysfunction.

Adult↗

PubMed2001

Penile and perianal pudendal nerve somatosensory evoked potentials in the diagnosis of erectile dysfunction.

Neurophysiologic examinations in differential diagnosis of erectile dysfunction comprise electromyogramme of the pelvic floor, pudendal nerve terminal motor latency (PNTML) and evaluation of pudendal somatosensory evoked potentials (SSEP). We focused our interest on comparing diagnostic importance of penile and perianal pudendal nerve SSEP. We examined 20 patients suffering from erectile dysfunction and 20 patients without any manifestation of impotence. The stimulus was administered using penile ring electrodes at the base of the penis (cathode) and distally on the penis shaft (anode), as well as a perianal surface electrode applied at 3 o'clock in lithotomy position and 5 cm laterally on the gluteal skin. The potentials were recorded with intradermal needle electrodes at C(z)-2 cm (different) and F(z) (indifferent). 500 stimuli were averaged for a single tracing. The stimulus strength was set at an average of 3-4 times the stimulus threshold. Cortical latency of P 40 ranged from 39.0 to 45.6 ms (penile) and from 33.6 to 43.2 ms (perianal) in the control group, in the patient group latencies ranged from 38.8 to 51.6 (penile) and 34.0 to 44.8 ms (perianal). In two patients no potential was recordable after perianal stimulation, one patient showed a marked prolongation of the penile response with a normal perianal latency. Penile and perianal latencies of P 40 were significantly prolonged in the patient group compared to the control group (P<0.05). The combination of penile and perianal pudendal SSEP may provide valuable additional information in differential diagnosis of erectile dysfunction, especially allowing to identify different sites of neurogenic lesions. In contrast to perianal pudendal SSEP, penile stimulation may help to discover pathologic changes in the distal course of the pudendal nerve, especially the dorsal nerve of the penis.

Adult↗

PubMedDate not supplied

Safety and efficacy of sildenafil citrate in the treatment of male erectile dysfunction.

Sildenafil citrate, an oral therapy for erectile dysfunction, is a selective inhibitor of cyclic guanosine monophosphate (cGMP)-specific phosphodiesterase type 5 (PDE5), the predominant isozyme metabolizing cGMP in the corpus cavernosum. Chemically, it is a compound of the pyrazolo-pyrimidinyl-methylpiperazine class. Sildenafil has no direct relaxant effect on human corpus cavernosum but enhances the relaxant effect of nitric oxide (NO) on the corpus cavernosum by inhibiting PDE5, which is responsible for degradation of cGMP in this tissue. When sexual stimulation causes local release of NO, inhibition of PDE5 by sildenafil increases concentrations of cGMP in the corpus cavernosum, causing smooth muscle relaxation and blood flow into the penis, resulting in an erection. Sildenafil at recommended doses has no effect in the absence of sexual stimulation. The drug is rapidly absorbed after oral administration, with absolute bioavailability of 40%. Its pharmacokinetics are dose proportional over the recommended dosage range. Maximum plasma concentrations are reached within 30 to 120 minutes after oral dosing in the fasting state. Sildenafil is cleared predominantly by the hepatic microsomal isoenzymes CYP3A4 (major route) and CYP2C9 (minor route). Clinical studies assessed the effect of sildenafil on the ability of men with erectile dysfunction to engage in sexual activity and, specifically, to achieve and maintain an erection sufficient for satisfactory sexual intercourse. Sildenafil was evaluated at doses of 25, 50, and 100 mg in randomized, double-masked, placebo-controlled clinical trials of up to 6 months' duration. The drug was administered to hundreds of patients aged 19 to 87 years having erectile dysfunction of various etiologies for a mean duration of 5 years. Sildenafil was associated with statistically significant improvement in erectile function compared with placebo. Adverse effects reported at a rate of >2% were headache, flushing, dyspepsia, nasal congestion, urinary tract infection, abnormal vision, diarrhea, dizziness, and rash. No cases of priapism were reported. The use of sildenafil is contraindicated in men who are taking organic nitrates, because of the potential for a precipitous decrease in blood pressure. Postmarketing reports and surveillance have revealed at least 39 deaths with sildenafil use in men having a history of heart disease, men taking nitrate medications, and men in poor physical health due to lack of exercise. Many of the men who experienced serious adverse effects or death had a variety of concomitant diseases and were taking multiple medications.

Animals↗