Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0151744 (myocardial ischemia)
 31,282 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Erectile function in man depends upon a complex interaction of psychogenic, neurologic, hormonal and vascular factors, and therefore the management of erectile dysfunction (ED) reflects this complexity of control. Therapeutic options include psychological and non-pharmacological approaches as well as drug treatments. The effectiveness of the type-5 cGMP phosphodiesterase inhibitor sildenafil citrate (Viagra) confirms the pivotal role of the NO-cGMP axis in promoting and maintaining erection. Although widely acclaimed, sildenafil leaves many questions unanswered, especially regarding its susceptibility to pharmacokinetic drug interactions, and its safety in patients with ischaemic heart disease and those taking nitrates. In view of the epidemiological link between erectile dysfunction and cardiovascular disease in the elderly, this limitation might have much broader implications. The presently available scientific documentation, although less extensive, indicates that NO donors, such as topically applied nitroglycerin (GTN; for example, 1-2 puffs of an ordinary GTN spray applied to the shaft of the penis), might be a reasonable alternative. Further larger-scale research on the efficacy and tolerability of topical GTN is needed to establish its full therapeutic potential in the treatment of erectile dysfunction.
 ...
PMID:Opportunities for the treatment of erectile dysfunction by modulation of the NO axis--alternatives to sildenafil citrate. 989 Nov 91

Erectile dysfunction is a common condition in men with cardiovascular disease, probably as a result of shared factors that impair hemodynamic mechanisms in the penile and ischemic vasculature. Sildenafil citrate, an orally active, selective inhibitor of phosphodiesterase type 5 (PDE5), has demonstrated excellent efficacy and safety profiles in men with erectile dysfunction of various etiologies. Sildenafil administration is contraindicated in patients who are taking nitrates or nitric oxide donors. This retrospective subanalysis of data from double-blind, placebo-controlled studies assessed the efficacy (9 studies) and safety (11 studies) of sildenafil in patients with erectile dysfunction and ischemic heart disease who were not taking nitrates. Of 3,672 patients randomized to receive sildenafil (5-200 mg) or placebo for 4-24 weeks in 11 double-blind, placebo-controlled studies, 357 (10%) reported a history (past or present) of ischemic heart disease and were not taking nitrates. Efficacy was assessed using end-of-treatment responses to Question 3 (ability to achieve an erection) and Question 4 (ability to maintain an erection) of the International Index of Erectile Function (IIEF), scores for the 5 domains of male sexual function assessed by the IIEF (erectile function, orgasmic function, sexual desire, intercourse satisfaction, and overall satisfaction), and responses to a global efficacy question ("Did the treatment improve your erections?"). The responses to the 2 IIEF questions were graded on a scale of 1 (almost never or never) to 5 (almost always or always), with a score of 0 indicating no attempt at sexual intercourse. At the end of treatment, the mean scores for Question 3 and Question 4 of the IIEF for patients with erectile dysfunction and ischemic heart disease were significantly higher for the sildenafil group than for the placebo group (p <0.0001). Mean end-of-treatment scores for the IIEF domains also demonstrated significant increases for sildenafil-treated patients compared with those receiving placebo (p <0.05). At the end of treatment, improved erections were reported by 70% of patients who received sildenafil and by 20% of those in the placebo group p <0.0001). For the sildenafil group, the incidences of the most common adverse events (headache 25%, flushing 14%, and dyspepsia 12%) for patients with ischemic heart disease were similar to those in patients without this concomitant illness (21%, 15%, and 10%, respectively). Moreover, the overall incidence of cardiovascular adverse events other than flushing was comparable in patients with and without ischemic heart disease for both treatment groups. Since there is a degree of cardiac risk associated with sexual activity, clinicians should consider the patient's cardiovascular status before initiating any treatment for erectile dysfunction. Physicians should be aware that patients with underlying cardiovascular disease could be adversely affected by the vasodilator effects of sildenafil, especially in combination with sexual activity. The results of the present subanalysis indicate that oral sildenafil significantly improves erectile function and is well tolerated in patients with erectile dysfunction and ischemic heart disease who are not taking nitrate therapy.
 ...
PMID:Efficacy and safety of sildenafil citrate in the treatment of erectile dysfunction in patients with ischemic heart disease. 1007 40

Sildenafil citrate is the first orally active therapy proved to be effective and safe treatment for erectile dysfunction (ED). Because men with cardiovascular disease are at increased risk of developing ED, and because ED and cardiovascular disease share important risk factors, attention has focused recently on the use of sildenafil in these men. When used in combination with nitroglycerin and other nitric oxide (NO) donors, sildenafil may potentiate major drops in blood pressure. Use of nitrate antianginal agents are an absolute contraindication to sildenafil use. In normotensive men and in men receiving antihypertensive medications evaluated in Phase II/III clinical trials, sildenafil use at the recommended doses (25-100 mg 1 hour before sexual intercourse and no more than once daily) was associated with modest, transient reductions in blood pressure and negligible effects on heart rate. In a more recent study, sildenafil was well tolerated in patients receiving antihypertensive medications and was not associated with major decreases in blood pressure. From the time of its approval in the United States in March 1998 through mid-November 1998, with approximately 6 million prescriptions written, 130 deaths were reported by the US Food and Drug Administration (FDA). Seventy-seven of the men who died had documented cardiovascular events. Sixteen men took or were administered nitroglycerin or an organic nitrate; 3 others had nitroglycerin in their possession. Physician prescribing guidelines issued by the American College of Cardiology/American Heart Association (ACC/AHA) recommend caution when prescribing sildenafil to men with certain cardiovascular conditions, liver or kidney disease, and to those taking medications that may prolong sildenafil's half-life (e.g., erythromycin or cimetidine). Those with known or suspected coronary artery disease may benefit from an exercise test to determine whether resumption of sexual activity with use of sildenafil is likely to be associated with an increased risk of myocardial ischemia.
 ...
PMID:Cardiovascular effects of sildenafil citrate and recommendations for its use. 1050 71

Sildenafil citrate is the first oral agent approved for the treatment of erectile dysfunction (ED); other oral agents are in the process of development. Because the mechanism of action of many of these agents involves vasodilation, there is a potential for interaction with the cardiovascular system. Sildenafil inhibits phosphodiesterase-5 (PDE-5) which is found in the corpus cavernosum and in the systemic vasculature. Sildenafil causes a mild decrease in systemic arterial pressure ( approximately -8/-5.5 mm Hg); it causes a synergistic and often major decrease in systemic arterial pressure in the presence of organic nitrates (nitric oxide donors). Sildenafil is therefore contraindicated in patients taking organic nitrates. A review was made of clinical trials in populations of men with (1) erectile dysfunction; (2) chronic stable ischemic heart disease and erectile dysfunction; and (3) hypertension and erectile dysfunction. This review showed that sildenafil was effective and not associated with an increase in serious cardiovascular adverse events, myocardial infarction (MI), or death compared with placebo. Although there have been spontaneous reports of death among men using sildenafil, there are limitations to spontaneous-event reporting. In addition. the numbers of such reports are well below the expected numbers of deaths when considering the number of men who have received prescriptions for sildenafil and their age and cardiovascular risk factor profile. Because there is a small but finite risk of having a cardiac event with sexual activity, physicians should discuss with their cardiac patients the risks of sexual activity before prescribing any treatment for ED. In addition, they should evaluate their patients' cardiac status when considering the safety of administering any ED treatment that may have systemic vasodilatory properties and can potentially lower blood pressure. In some cases, exercise treadmill testing may be warranted to determine whether ED patients with coronary artery disease can achieve the physiologic workload (4-6 metabolic equivalents) associated with sexual intercourse.
 ...
PMID:Cardiovascular risk and sildenafil. 1089 81

With the earlier detection of prostate cancer and the increasing demand for treatment of organ-confined dizease, quality of life issues are becoming more important. Development of erectile dysfunction (ED) following radical therapy is a particular concern, and occurs in perhaps a third of patients treated by radiotherapy and 30-70% of patients treated by radical prostatectomy. Although it is assumed that the ED relates to damage to the nerves subserving erection, this view has been questioned recently and in at least a proportion of patients the cause appears to be vascular. Despite the likely cause of their ED, all patients presenting with ED after treatment for prostate cancer should undergo assessment by history and examination to ensure that there are no other correctable risk factors. Patients can then be considered for a number of treatment options, and currently sildenafil (Viagra, Pfizer) is usually used as first-line therapy assuming there are no contraindications, such as severe ischaemic heart disease or nitrate therapy. Sildenafil improves erectile function in 70% of patients with ED post-radiotherapy, but appears less effective in men after radical prostate surgery with a response rate of 40-50%. Other treatment options include self-injection or intra-urethral administration of alprostadil, and some patients are happy to use a vacuum erection device. Finally, if all else fails, patients may be suitable for penile implant surgery.
 ...
PMID:Erectile dysfunction following radical therapy for prostate cancer. 1110 90

Diabetes can induce sexual disorders by different mechanisms. These troubles are more frequent in diabetics subjects. Thus, management of sexual impotence is an important aspect of diabetes care. However, most diabetologists are not trained to treat sexual disorders. The recent availability of oral drugs, i. e. Sildenafil (Viagra), has partly simplified the treatment of sexual impotence, particularly in diabetic patients. However, Viagra is efficient in only 60% cases in diabetic subjects. In the remaining cases, intracavernosal injections or vacuum can be used. Since Viagra has been available, more diabetic patients complained with sexual disorders, and ask for treatment of impotence. Cardio-vascular diseases must retain more attention in diabetic patients who are exposed to silencious myocardial ischemia. In such subjects, Viagra is not contra-indicated, but must be used after myocardial explorations, especially if the patients have cardio-vascular risk factors. However, patients and their doctors have been threatened by death cases reported with Viagra in United States. The lack of detailed informations has restrained Viagra's prescription. The following explains how to manage sexual disorders as part of diabetes care, and suggests rules for Viagra's prescription in diabetic patients.
 ...
PMID:[How to prescribing Viagra in practice...]. 1111 23

Sildenafil citrate is the first oral phosphodiesterase type 5 inhibitor approved for the treatment of erectile dysfunction. The wide use of sildenafil by patients with erectile dysfunction and cardiovascular disease has resulted in a considerable number of independent studies investigating the cardiovascular safety and functional role of the phosphodiesterase type 5-cyclic guanosine monophosphate-nitric oxide pathway in the cardiovascular system. Endothelial dysfunction, defined as a reduction in the bioavailability of nitric oxide, is associated with many of the common risk factors for cardiovascular disease and erectile dysfunction. Sildenafil has been demonstrated to improve the vasomotor aspect of endothelial dysfunction in patients with heart failure and diabetes. Hemodynamic studies suggest that sildenafil is a modest vasodilator with the potential to increase coronary blood flow and coronary flow reserve. In patients with ischemic heart disease, sildenafil is associated with reductions in mean arterial and pulmonary pressure with little effect on heart rate, cardiac output, and systemic or pulmonary vascular resistance. The absence of an effect on cardiac output supports the lack of an inotropic effect of sildenafil. This is consistent with the finding that sildenafil has no effect on cyclic adenosine monophosphate levels in the vasculature. Finally, exciting reports have emerged from clinical experience with the use of phosphodiesterase type 5 inhibitors in patients with pulmonary hypertension.
 ...
PMID:Coronary and systemic hemodynamic effects of sildenafil citrate: from basic science to clinical studies in patients with cardiovascular disease. 1241 49

Erectile dysfunction medications such as sildenafil citrate (Viagra) or tadalafil (Cialis) are commonly prescribed worldwide. They are selective phosphodiesterase-5 inhibitor and partial phosphodiesterase-6 inhibitors causing smooth muscle relaxation in the corpus cavernosum, allowing penile vasodilatation and erection in response to sexual stimuli. Over the years, there have been an increasing number of case reports concerning patients who developed ischemic optic neuropathy soon after the ingestion of these drugs. Although a cause and effect relationship between usage of the drugs and the development of ischemic optic neuropathy is difficult to prove, it is common nowadays to advise patients, especially those suffering from diabetes, hypertension, and ischemic heart disease, regarding the potential risk of visual loss due to ischemic optic neuropathy and treatment with erectile dysfunction drugs. Patients who were diagnosed with ischemic optic neuropathy soon after the ingestion of these erectile dysfunction drugs should be warned about a similar event in their fellow eye and should be advised regarding drug discontinuation.
 ...
PMID:[Non-arteritic anterior ischemic optic neuropathy associated with erectile dysfunction medications]. 2351 98

Sildenafil, a phosphodiesterase-5 inhibitor sold as Viagra, is a cardioprotector against myocardial ischemia/reperfusion (I/R) injury. Our study explored whether sildenafil protects against I/R-induced damage in a porcine cardiac arrest and resuscitation (CAR) model via modulating the renin-angiotensin system. Male pigs were randomly divided to three groups: Sham group, Saline group, and sildenafil (0.5 mg/kg) group. Thirty min after drug infusion, ventricular fibrillation (8 min) and cardiopulmonary resuscitation (up to 30 min) was conducted in these animals. We found that sildenafil ameliorated the reduced cardiac function and improved the 24-h survival rate in this model. Sildenafil partly attenuated the increases of plasma angiotensin II (Ang II) and Ang (1-7) levels after CAR. Sildenafil also decreased apoptosis and Ang II expression in myocardium. The increases of expression of angiotensin-converting-enzyme (ACE), ACE2, Ang II type 1 receptor (AT1R), and the Ang (1-7) receptor Mas in myocardial tissue were enhanced after CAR. Sildenafil suppressed AT1R up-regulation, but had no effect on ACE, ACE2, and Mas expression. Sildenafil further boosted the upregulation of endothelial nitric oxide synthase (eNOS), cyclic guanosine monophosphate (cGMP) and inducible nitric oxide synthase(iNOS). Collectively, our results suggest that cardioprotection of sildenafil in CAR model is accompanied by an inhibition of Ang II-AT1R axis activation.
 ...
PMID:Sildenafil Protects against Myocardial Ischemia-Reperfusion Injury Following Cardiac Arrest in a Porcine Model: Possible Role of the Renin-Angiotensin System. 2656 34

Male erectile dysfunction is common and frustrating after the age of forty years. Erectile dysfunction is a cause of misery, relationship difficulties, and significantly reduced quality of life. Sildenafil citrate (Viagra) has shown promising results in recently published clinical trials. Sildenafil is a potent and competitive inhibitor of cGMp specific phosphodiesterase-5, predominant isoenzyme in the human corpus cavernosum. It is effective in erectile dysfunction of diverse origin, however it requires a patent vascular system to be effective. It is not effective in patients with endocrinal impotence, loss of libido, premature ejaculation or infertility. Its main adverse effects are headache, flushing, dyspepsia, diarrhoea, nasal congestion, indigestion, visual disturbances, dizziness and rash. Ventricular tachycardia and acute myocardial infraction have been reported in patients of ischaemic heart disease after consumption of sildenafil. Six deaths have been reported in patients taking nitrates. In India it is likely to be prescribed by a primary care physician without complete evaluation of patient on complaint of impotence. Hence the ethical question of who should prescribe this drug should be addressed by medical fraternity and proper guidelines formulated to avoid misuse of sildenafil. Phosphodiesterase is distributed in nerve, central nervous system, and systemic vasculature, hence long-term effects of drug on these tissues has to be ascertained. It should be made mandatory to report all adverse drug reactions to ADR monitoring centres. It is a wonder for those who require it, but has potentially dangerous adverse effects and drug interactions and hence is and not a wonder pill for all kinds of impotence.
...
PMID:VIAGRA : IS IT A WONDER DRUG ? 2736 78


1