The Neurobiological Pathway Targeted by Sildenafil for PE

In 1990, Fein reported on a small group (N = 8) of patients with PE who used vasoactive intracavernosal pharmacotherapy (mixture of phentolamine mesylate [1.0 mg/mL] and papaverine hydrochloride [30 mg/mL]) to address their PE [90].

Do these medications cause erections without sexual stimulation?

More recently, in a single-blind, placebocontrolled, crossover, stop-watch study, these findings were confirmed using the 25-mg dose in 60 patients with lifelong PE [78]. The overall mean increase in IELT was from 0.79 to 6.20, as opposed to a minimal 0.84 in the crossed over placebo treatment arm (P = <0.0001). Mild side effects were experienced in eight patients (13.3%), consisting of mild dyspepsia and somnolence [78]. The association of erectile dysfunction (ED) with rapid ejaculation has been reported in important epidemiological studies, and PE may be seen in up to a third of patients with ED [80,81]. It is generally accepted that the association between PE and ED may be rooted in a compensatory mechanism where a man with PE develops ED simply as a result of the anxiety associated with the condition, and conversely, a patient suffering from ED may ejaculate early in the course of his erection before the failure-to-maintain phase of the erection sets in. When exploited as a temporary intervention, these artificially induced erections provided patients with confidence and encouragement, while they were awaiting results from more conventional therapies. With dosages ranging from 0.10 to 0.40 mL, the author reported that all eight patients responded successfully to this approach, while three were apparently “cured” of PE. The other five patients in the study continued to use ICIs after the completion of the study. An open-label study involving 80 potent men found that the combined use of sildenafil and paroxetine proved more efficacious than either treatment alone [69]. In treating 138 men with a progressive armamentarium of treatments, Chen et al. obtained best results when the use of sildenafil was combined with SSRIs and behavioral counseling. Sildenafil in combination with paroxetine was effective in97%of patients, compared to an improvement for only 47% using paroxetine alone [91].

Material and Methods

Kriegsfeld and colleagues set out to study the effects of eNOS on sexual function, and discovered that male mice missing the gene for eNOS exhibited significant abnormalities in ejaculatory function. More specifically, the data from their animal study suggest that ejaculatory function may be inhibited by nitric oxide from eNOS in nongenetically altered mice, and that this effect is most likely achieved by decreasing sympathetic nervous system activity to prevent PE [85]. The authors hypothesized that administration of medications peripherally that can selectively increase eNOS may be effective in treating PE with minimal central nervous system adverse events. Patients with lifelong PE, as opposed to those with acquired or late-onset PE, are reported to have a 50% rate of concomitant ED. Nevertheless, the value of PDE5 inhibitors in the treatment of PE alone has not been established. An alternate approach combines the use of oral agents with the concomitant application of topical solutions. For example, oral fluoxetine, when reinforced by the topical application of lidocaine ointment, effected a “cure” or an improvement in 83.3% of men, compared with 72% of those treated with fluoxetine alone [92]. Combining a psychotherapeutic with a pharmaceutical approach can provide either a stepwise or concurrent integration of psychological and medical interventions [93]. Several investigators have documented the added value of combining psychotherapy with pharmacotherapy in the treatment of ED, utilizing care models that should transfer readily to the integrated multidisciplinary management of PE [33].

Sildenafil Dapoxetine Tablets

Although the ejaculatorydelaying mechanism of tramadol has not been fully understood, it is hypothesized that this may be related to tramadol’s effect on inhibition of reuptake of norepinephrine and serotonin [78]. In 2006, Safarinejad and Hosseini published the results of their evaluation of the safety and efficacy of this serotonergic drug in delaying ejaculation. A double-blinded, placebo-controlled, fixed-dose study demonstrated a 13-fold increase in IELT with the on-demand use of 50 mg of Tramadol [79]. Among the 57 patients who completed the study, the mean IELT after tramadol and placebo increased from a baseline of 19 and 21 seconds to 243 and 34 seconds, respectively. Although more adverse events were noted when the patients were on tramadol, the authors did not report any study withdrawals because of medication-related adverse events. Sildenafil has proven helpful as an adjunctive measure in support of a program of SSRI therapy, when combined with psychosexual counseling [91]. Advance in the understanding of PE has been hobbled by a categorical lack of solid studies on which to base clinical decision making. As a case in point, an attempt at performing a meta-analysis of all studies, which evaluate the potential for PDE5 inhibitors in the treatment of PE, found that only 2 of 14 studies assessed the patient’s reaction to his problem (“bother score”), and none took into consideration the partner’s distress.

What are the available dosages of Lovegra?

An alternative, but related, view held by other investigators suggests that PE and ED share a vicious circle, where the level of excitation is instinctively reduced by a man with PE trying to control his ejaculation (thus leading to ED), and conversely, a man suffering from ED will try to increase his excitation to achieve an erection, thus leading to a rapid ejaculation [82]. In cases of PE associated with ED, treatment of ED by using PDE5 inhibitors may have a salutary effect on ejaculatory dysfunction [83]. Mancina and colleagues have demonstrated the expression of PDE5 in all the muscular layers of human and rabbit vas deferens [84]. Based on their findings documenting the presence of this enzyme in the ejaculatory tract, the authors postulated a potential direct effect of PDE5 inhibitors in mediating ejaculatory function. Experiments with knockout mice suggest that endothelial nitric oxide synthase (eNOS) gene deletion may adversely affect ejaculatory as well as erectile function. Only 1 of the 14 studies met the criteria for an evidence-based, double-blinded, placebo-controlled investigation, using validated outcome assessment tools and including objective physiological measurements [83]. The artificiality involved in studying PE under conditions necessary for objective, physiological measurement conflicts with attempts to understand, evaluate, and treat PE in its natural setting. Findings derived from studies of stopwatch timed, methodically recorded intercourse do not necessarily correlate well with performance under more spontaneous, private, and intimate circumstances. On the brighter side, a most welcome addition to the field is the recent development and validation of a “user-friendly” questionnaire in 2007 to capture the multidimensional nature of PE and lend objectivity to diagnosing this entity [94]. A permanent cure for PE remains a distant goal. In the interim, ideal medical treatment for PE would entail the development of a medication that is effective on a rapid-acting, “on-demand” basis, without impairing the spontaneity and intimacy of the relationship.

Dosage of Fildena Super Active

In a placebo-controlled trial in 84 patients, sildenafil proved ineffective, either alone or in combination with topical therapy, in the treatment of acquired PE [2]. PDE5 inhibitors may exert a secondary benefit for patients with PE when they (i) allow for a sustained penile erection, even after ejaculation; (ii) facilitate a second intercourse after the initial ejaculation, which is often less prone to PE; and/or (iii) help the patient to overcome performance anxiety, which often exacerbates PE [83,89]. However, it is deemed unlikely that PDE5 inhibitors have a significant role in the treatment of PE—with the exception of men with acquired PE secondary to ED [1]. The use of ICI for “treatment” of PE is not supported by a large body of peer-reviewed literature, and is infrequently used in clinical practice. However, ICI has been used as a strategy in certain cases to allow men with PE to maintain their erections and continue satisfactory sexual intercourse despite rapid ejaculation. Sexual side effects (e.g., diminished libido and ED), as well as generalized side effects (e.g., nausea, insomnia, and headache), would be avoided.

Dosages of Sildenafil

A crossover study of 31 potent men with lifelong PE found sildenafil treatment to be associated with a significantly higher IELT and higher sexual satisfaction score than any other therapy including the use of any one of a variety of SSRIs and the use of the squeezepause method [1,86]. Sildenafil was deemed “decidedly the most effective” and was recommended as a valid alternative to the use of SSRIs in the treatment of PE. Conversely, the presence of concomitant PE did not impair patient satisfaction with their improved erections, when men were treated with PDE5 inhibitors for their ED [87]. A recent review found that of five studies, three have concluded that the use of PDE5 inhibitors was helpful, even superior, in treating PE, while two placebo-controlled studies found no such improvement [88]. The single study, which used objective, double-blinded, placebo-controlled measures, found no improvement in PE following PDE5 inhibitors in men who did not also have associated ED [83]. Novel topical therapies in the form of aerosol (i.e., TEMPE, Plethora Solutions; London, UK) and short-acting SSRI compounds that target the serotonergic system are currently undergoing clinical trials in the United States. Alza/Johnson & Johnson is soliciting an FDA approval for dapoxetine. Pfizer and Bristol-Myers Squibb also have patented agents under development [56]. Although specific data about these compounds are not available at the time of this writing, the Pfizer medication (UK 390957, Pfizer Inc., New York,NY, USA) has been described as a rapid-acting serotonin modulator, i.e., a short-acting SSRI [95].