Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0018681 (headache)
56,091 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Vardenafil (Levitra), recently launched in Belgium by Bayer and Glaxo-SmithKline, is a new drug that potently and selectively inhibits phosphodiesterase type 5 (PDE5) in the cavernosum tissue of the penis. Inhibition of PDE5 blocks the hydrolysis of cyclic guanosine monophosphate (GMPc) and results in increased arterial blood flow leading to enlargement of the corpus cavernosum and resulting in erection. In controlled clinical trials, vardenafil at least doubled the rate of successful erections as compared to placebo, whatever the evaluation parameter considered and the subgroup of patients studied. Vardenafil is thus indicated in the treatment of patients with erectile dysfunction. It is presented as 5, 10 and 20 mg tablets and the usual dose is 10 mg to be ingested 25 to 60 minutes before sexual activity. Vardenafil has a more potent inhibitory activity of PDE5 in vitro than sildenafil or tadalafil while its pharmacokinetics in vivo is somewhat more rapid than that of the two other compounds. The dosage of vardenafil may be reduced to 5 mg (especially in older individuals) to improve tolerance or be increased up to 20 mg (especially in the presence of organic diseases aggravating erectile dysfunction) to improve efficacy. Contra-indications (co-administration with drugs increasing nitric oxide) and side-effects (headache and flushing due to vasodilatation) of vardenafil are similar to those of other PDE5 inhibitors.
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PMID:[Medication of the month. Vardenafil (Levitra)]. 1462 53

This was a double-blind, placebo-controlled, flexible-dose study of the efficacy and safety of sildenafil in men with erectile dysfunction (ED) and clinically stable coronary artery disease (CAD). Patients were randomized to receive sildenafil or placebo for 12 weeks. Primary outcomes were questions 3 and 4 of the International Index of Erectile Function (IIEF). Secondary outcomes included the other IIEF questions and functional domains, the Life Satisfaction Checklist, the Erectile Dysfunction Inventory of Treatment Satisfaction, 2 global efficacy assessment questions, and intercourse success rate. By week 12, sildenafil-treated patients (n = 70) showed significant improvements on questions 3 and 4 compared with placebo-treated patients (n = 72; p <0.01). Larger percentages of sildenafil-treated patients reported improved erections (64%) and improved intercourse (65%) compared with placebo-treated patients (21% and 19%, respectively). Sildenafil-treated patients were highly satisfied with treatment and their sexual life compared with placebo-treated patients. Forty-seven percent of sildenafil- and 32% of placebo-treated patients experienced adverse events, including transient headache, hypertension, flushing, and dyspepsia. There were no serious drug-related cardiovascular effects. Thus, sildenafil is an effective and well-tolerated treatment for ED in men with CAD. Sildenafil was not associated with additional safety risks in this patient population.
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PMID:Efficacy and safety of sildenafil citrate in men with erectile dysfunction and stable coronary artery disease. 1471 38

Orally administered phosphodiesterase type 5 (PDE5) inhibitors have become the first-line treatment option for erectile dysfunction (ED). Vardenafil is a potent and highly selective PDE5 inhibitor developed as an oral therapy for ED. Two pivotal, randomised, double-blind, multi-centre studies have evaluated the use of vardenafil in men with ED. Vardenafil improved the rate of achieving and maintaining an erection during sexual intercourse. Improvement was also noted in other aspects of sexual function, including confidence, orgasmic function and overall satisfaction. Vardenafil produces clinically and statistically significant improvements in erectile function regardless of age, baseline severity and aetiology and is efficacious for the treatment of ED in diabetic and postradical prostatectomy patients. Vardenafil has a rapid onset of action, in which erections sufficiently rigid for eventual intercourse completion can be achieved as early as 16 min after ingestion. Vardenafil 20 mg has sustained long-term efficacy by providing up to 92% of patients with improved erections during > 2 years of treatment. Vardenafil is well-tolerated, with an adverse event profile typical of this class of PDE5 inhibitors. The most common adverse events were headache, flushing, rhinitis and dyspepsia, which were mild-to-moderate in severity and they generally attenuated with continued use. Vardenafil may be associated with transient reductions in blood pressure and commensurate increases in heart rate, with the overall incidence of cardiovascular-related adverse events similar to that of placebo. Although claims can be made about potential features of benefit for each of the currently marketed PDE5 inhibitors, there are at present, no non-pharmaceutical company sponsored, peer-reviewed, head-to-head trials that have been published.
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PMID:Vardenafil: a novel type 5 phosphodiesterase inhibitor for the treatment of erectile dysfunction. 1510 74

The mechanism of action of the phosphodiesterase type 5 (PDE5) inhibitors (i.e., sildenafil, tadalafil, and vardenafil) involves inhibition of the PDE5 isoenzyme located in penile vascular smooth muscle cells. Sexual stimulation triggers the release of nitric oxide (NO), stimulating the release of guanylyl cyclase, leading to an increase in intracellular cyclic guanosine monophosphate (cGMP) concentrations, a decrease in intracellular calcium, and ultimately relaxation of the vascular smooth muscle in the corpus cavernosum and penile erection. The PDE5 inhibitors have no effect on the penis in the absence of sexual stimulation. Although the various PDE5 inhibitors differ with respect to selectivity and pharmacokinetic profiles, efficacy and safety of these agents are comparable in broad populations of men with erectile dysfunction (ED), including those with diabetes or those taking multiple antihypertensive agents. The most frequently reported adverse events of the PDE5 inhibitors are related to their mild vasodilatory effects and include headache, flushing, dyspepsia, and nasal congestion or rhinitis. Side effects are generally reversible and tend to diminish during continued treatment. Differences in pharmacokinetic properties among the PDE5 inhibitors include the fact that sildenafil and vardenafil have a shorter duration of action (approximately 4 h) compared with the longer period of responsiveness observed with tadalafil (up to 36 h). In addition, in the presence of high-fat food, absorption of sildenafil and vardenafil may be delayed; however, the rate and extent of tadalafil absorption are unaffected by high-fat food.
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PMID:Phosphodiesterase type 5 inhibitor differentiation based on selectivity, pharmacokinetic, and efficacy profiles. 1511 91

Trials of the efficacy and safety of vardenafil in the treatment of male erectile dysfunction (ED) were meta-analysed. All available databases were searched (January 1, 2001-November 30, 2003). Trials were eligible if they included men with ED, compared vardenafil with placebo, were randomized, were at least of 12 weeks duration, and assessed clinically relevant outcomes. Two reviewers independently evaluated study quality and extracted data in a standardized fashion. Nine trials (6809 men) met the inclusion criteria. In results pooled from seven fixed-dose trials, vardenafil increases the Erectile Function domain of the International Index of Erectile Function questionnaire by 6.18 units (weighted mean difference (WMD)). Vardenafil also increases the percentage of erections firm enough to allow vaginal penetration (WMD: 26) and the percentage of sexual attempts that were successful per participant (WMD: 29.8). The percentage of men agreeing with the statement that 'the treatment they have been taking over the past 4 weeks improved their erections', is also in favour of vardenafil (relative risk (RR): 3). These efficacy variables appeared greater at higher doses, although there are no significant differences between 10 and 20 mg dose. The same results were extracted for the two flexible 'as needed' dosing trials. Discontinuations are greater at the vardenafil groups compared to placebo (RR: 2.25). Specific adverse events with vardenafil included flushing, dyspepsia, headache, and rhinitis. Vardenafil was not significantly associated with serious cardiovascular events or death. Vardenafil, in all treatment regimens, shows to possess superior efficacy to placebo in the treatment of patients with erectile dysfunction. More data is needed on patients' subgroups.
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PMID:Vardenafil (Levitra) for erectile dysfunction: a systematic review and meta-analysis of clinical trial reports. 1522 25

Sildenafil revolutionised the treatment of erectile dysfunction (ED) on its introduction in 1998. Not only is it effective, but is, perhaps even more importantly, an extremely acceptable manner in which to treat ED (i.e., oral pharmacotherapy), compared to the other treatments that were available at that time (e.g., intracavernosal injection). Whilst sildenafil remains the market leader for ED treatment, it does have some shortcomings: its clinical efficacy is diminished in 'difficult to treat' patient groups, such as diabetics, side effects, such as blue-tinged vision and headache, and the need to time the ingestion of sildenafil to 1 h prior to expected time of sexual intercourse. Recently, newer phosphodiesterase inhibitors ('sons of viagra') have become available, and potentially to improve upon, what has become regarded as the gold standard for ED treatment. This review article discusses the differences between vardenafil, tadalafil and sildenafil, in order to allow the clinician to make an informed decision as to which phosphodiesterase inhibitor to prescribe when dealing with the ever expanding number of patients seeking help for ED.
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PMID:New phosphodiesterase inhibitors in the treatment of erectile dysfunction. 1550 Mar 70

In order to investigate the safety and efficacy of sildenafil prescribed in primary care, a post-marketing surveillance study was undertaken. A total of 651 men with erectile dysfunction (ED) were enrolled from 31 family physicians in Korea from December 1999 to July 2002. Patients were regularly followed up to ascertain the safety and efficacy of sildenafil. Of the 651 patients enrolled, 572 (87.9%) returned for safety evaluation and efficacy assessment. In all, 458 (80.1%) of 572 patients reported improved erectile function with sildenafil. Hypertension, diabetes and low-dose sildenafil were associated with poor efficacy. A total of 71 adverse events were reported among 56 patients (8.6%), with the most frequent being hot flushes (5.6%), followed by headache (2.6%), palpitation (1.0%), anxiety (0.5%) and elevated ALT (0.5%). Only six patients (1.0%) discontinued sildenafil as a direct result of adverse events. These results suggest that sildenafil prescribed by primary care physicians was well tolerated and improved erectile function in patients with ED.
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PMID:Post-marketing surveillance study of the safety and efficacy of sildenafil prescribed in primary care to erectile dysfunction patients. 1551 Jan 93

Erection is a neurovascular event that involves spinal and supra spinal pathways. The final common pathway involves the release of nitric oxide (NO) from both endothelial cells and neurons, which acts as a vasodilator causing penile engorgement and erection. NO is degraded by the enzyme phosphodiesterase (PDE) type 5 in the penis. Erectile dysfunction (ED), defined as the persistent inability to achieve and/or maintain an erection sufficient for satisfactory sexual performance, results when the neurovascular pathway is interrupted by medical conditions or drugs. A 15-item self-administered questionnaire, the International Index of Erectile Function (IIEF), is one of the most useful tools to evaluate erectile function (EF) in clinical trials, although of much less use in routine clinical practice. The MMAS (Massachusetts Male Aging Study) was the first major epidemiological investigation to study the prevalence of ED. The study found that ED was three times more common in patients with diabetes mellitus. The aetiopathogenesis of ED in diabetes is multifactorial, with vascular and neural factors being equally implicated. Hyperglycaemia is believed to give rise to biochemical perturbations that lead to these microvascular changes. In the MMAS, ED in diabetes was strongly correlated with glycaemic control, duration of disease and diabetic complications. The incidence increased with increasing age, duration of diabetes and deteriorating metabolic control, and was higher in individuals with type 2 diabetes than those with type 1.ED in men with diabetes often affects their quality of life and, as patients are often reluctant to come forward with their symptoms, a carefully taken history is one of the most useful approaches in identifying affected individuals. The PDE inhibitors have revolutionised the management of ED and oral drug therapy is currently first-line therapy for the condition. These agents act by potentiating the action of intracavernosal NO, thereby leading to a more sustained erection. Sildenafil was the first PDE5 inhibitor to undergo evaluation and has been studied extensively. More recently two other agents, vardenafil and tadalafil, have been introduced. All the drugs have been shown to be effective across a wide range of aetiologies of ED, including diabetes. The drugs have been shown to improve EF domain scores, penetration and maintenance of erection, resulting in more successful intercourse. Their effects are greater at higher doses. Sildenafil and vardenafil are shorter-acting agents, while tadalafil has a longer half-life allowing the user more flexibility in sexual activity. Common adverse effects include headache, nasal congestion and dyspepsia, all actions related to inhibition of PDE5. The drugs are generally well tolerated and withdrawal from the clinical studies as a result of drug-related adverse effects were rare. The use of PDE5 inhibitors in the presence of oral nitrates is absolutely contraindicated. The clinical studies to date have not evaluated the use of one drug in the case of treatment failure with another agent. Sublingual apomorphine, which stimulates central neurogenic pathways, is a new agent and may be a suitable alternative in those patients in whom PDE5 inhibitors are ineffective or contraindicated. In clinical trials, all IIEF domains except sexual desire were found to have improved after apomorphine. The median times to erection in these studies were 18.9 and 18.8 minutes for the 2 and 3mg doses, respectively. Intraurethral and intracavernosal alprostadil may be a useful alternative when oral drug therapy is ineffective or contraindicated. The management of ED in the diabetic patient may often involve a multidisciplinary approach where psychosexual counselling and specialist urologist advice is required in addition to the skills and expertise of the diabetologist. Finally, the introduction of the new oral agents have completely revolutionised the management of ED and allowed more individuals to come forward for treatment.
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PMID:New treatment options for erectile dysfunction in patients with diabetes mellitus. 1553 69

Chronic heart failure (CHF) is an increasingly common cardiovascular disorder. Many patients who have CHF report moderate to marked decreases in the frequency of sexual activity, and up to 75% of patients report erectile dysfunction (ED). There are few controlled clinical data on the efficacy and safety of sildenafil citrate in men who have ED and CHF; thus, we evaluated these parameters in patients who had stable CHF. This was a double-blind, placebo-controlled, flexible-dose study. Men who had ED and stable CHF were randomized to receive sildenafil or placebo for 12 weeks. Primary outcomes were questions 3 and 4 of the International Index of Erectile Function. Secondary outcomes included the 5 functional domains of the International Index of Erectile Function, 2 global efficacy assessment questions, intercourse success rate, the Erectile Dysfunction Inventory of Treatment Satisfaction, and the Life Satisfaction Checklist. By week 12, patients who received sildenafil (n = 60) showed significant improvements on questions 3 and 4 compared with patients who received placebo (n = 72; p <0.002). Larger percentages of patients who received sildenafil reported improved erections (74%) and improved intercourse (68%) compared with patients who received placebo (18% and 16%, respectively). Intercourse success rates were 53% among patients who received sildenafil and 20% among those who received placebo. Patients who received sildenafil were highly satisfied with treatment and their sexual life compared with patients who received placebo. Sixty percent of patients who received sildenafil and 48% of patients who received placebo developed adverse events, including transient headache, facial flushing, respiratory tract infection, and asthenia. The incidence of events related to cardiovascular effects was low. Sildenafil is an effective and well-tolerated management of ED in men who have mild to moderate CHF.
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PMID:Efficacy and safety of sildenafil citrate in men with erectile dysfunction and chronic heart failure. 1561 91

Inhibitors of phosphodiesterase type 5 (PDE-5) are well established as an oral treatment for the majority of patients with erectile dysfunction (ED). PDE-5 is found in high concentration in smooth muscle cells of the corpora cavernosa. However, enzymes of the PDE family are also expressed in various other tissues, including the brain. Little is known about its effects on the central nervous system (CNS), although it has been suggested that PDE-5 inhibitors might cross the blood-brain barrier. Side effects, such as headache, nasal congestion, flushing, nausea, are much more common. We describe a patient who had a transient global amnesia (TGA) after his first-ever use of tadalafil, a potent PDE-5 inhibitor. Despite the fact that the aetiology of TGA has not entirely been clarified at present, we consider the hypothesis of a causal relationship as tempting with respect to the current hypotheses of TGA pathophysiology. This case, together with others, suggests that PDE-5 inhibitors might be capable of exerting adverse effects in the CNS. Physicians should be aware of the possibility of neurological disturbances when prescribing PDE-5 inhibitors for ED.
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PMID:Transient global amnesia after intake of tadalafil, a PDE-5 inhibitor: a possible association? 1567 2


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