Double-blind multicenter study comparing alprostadil alpha-cyclodextrin with moxisylyte chlorhydrate in patients with chronic erectile dysfunction

A comprehensive history of injection therapy for erectile dysfunction, 1982-2023

INTRODUCTION

Although oral phosphodiesterase 5 inhibitors represent a first choice and long-term option for about half of all patients with erectile dysfunction (ED), self-injection therapy with vasoactive drugs remains a viable alternative for all those who are not reacting or cannot tolerate oral drug therapy. This current injection therapy has an interesting history beginning in 1982.

OBJECTIVES

To provide a comprehensive history of self-injection therapy from the very beginnings in 1982 by contemporary witnesses and some members of the International Society for Sexual Medicine's History Committee, a complete history of injection therapy is prepared from eyewitness accounts and review of the published literature on the subject, as well as an update of the current status of self-injection therapy.

METHODS

Published data on injection therapy, as a diagnostic and therapeutic tool for ED, were reviewed thoroughly by PubMed and Medline research from 1982 until June 2023. Early pioneers and witnesses added firsthand details to this historical review. Therapeutic reports of injection therapy were reviewed, and results of side effects and complications were thoroughly reviewed.

RESULTS

The pioneers of the first hours were Ronal Virag (1982) for papaverine, Giles Brindley (1983) for cavernosal alpha-blockade (phentolamine and phenoxybenzamine), Adrian Zorgniotti (1985) for papaverine/phentolamine, and Ganesan Adaikan and N. Ishii (1986) for prostaglandin E1. Moxisylyte (thymoxamine) was originally marketed but later withdrawn. The most common side effect is priapism, with the greatest risk of this from papaverine, which has modified its use for therapy. Currently, prostaglandin E1 and trimixes continue to be the agents of choice for diagnostic and therapeutic use in ED. A recent agent is a mixture of a vasoactive intestinal polypeptide (aviptadil) and phentolamine.

CONCLUSIONS

After 40 years, self-injection therapy represents the medication with the highest efficacy and reliability rates and remains a viable option for many couples with ED. The history of this therapy is rich.

Efficiency of intracavernosal alprostadil and oral clomiphene citrate combination treatment in penile vasculogenic erectile dysfunction patients accompanied by late-onset hypogonadism

In this study, the efficiency of intracavernosal alprostadil + oral clomiphene citrate (CC) treatment in late-onset hypogonadism (LOH) accompanied by penile vasculogenic erectile dysfunction (PVED) in patients irresponsive to phosphodiesterase type 5 inhibitor treatment was evaluated. A total of 31 patients with concurrent PVED and LOH were included in the study. The patients were given intracavernosal alprostadil (10-20 μg) and oral CC (50 mg) every day for 12 weeks. Before and after treatment, a 15-question International Index of Erectile Function (IIEF-15) questionnaire, Erection Hardness Score (EHS), Sexual Encounter Profile (SEP)2 and SEP3 levels were analysed, and follicle stimulating hormone (FSH), luteinising hormone (LH), total testosterone and prostate-specific antigen (PSA) levels were measured. In all, 41.9% of patients had pure arterial deficiency, 19.3% had pure venous deficiency, and 38.7% had arterial + venous (mixed) deficiency. A significant increase was detected in total testosterone, FSH, LH and PSA values after treatment when compared to values before treatment (p < .001, p < .001, p < .001 and p = .034 respectively). A significant recovery was observed in IIEF-15 subscores, EHS and SEP2-SEP3 results. In PVED patients accompanied by LOH, intracavernosal alprostadil and oral CC combination is an efficient, low cost, safely applicable and tolerable treatment.

SOP conservative (medical and mechanical) treatment of erectile dysfunction

INTRODUCTION

Erectile dysfunction (ED) is the most frequently treated male sexual dysfunction worldwide. ED is a chronic condition that exerts a negative impact on male self-esteem and nearly all life domains including interpersonal, family, and business relationships.

AIM

The aim of this study is to provide an updated overview on currently used and available conservative treatment options for ED with a special focus on their efficacy, tolerability, safety, merits, and limitations including the role of combination therapies for monotherapy failures.

METHODS

The methods used were PubMed and MEDLINE searches using the following keywords: ED, phosphodiesterase type 5 (PDE5) inhibitors, oral drug therapy, intracavernosal injection therapy, transurethral therapy, topical therapy, and vacuum-erection therapy/constriction devices. Additionally, expert opinions by the authors of this article are included.

RESULTS

Level 1 evidence exists that changes in sedentary lifestyle with weight loss and optimal treatment of concomitant diseases/risk factors (e.g., diabetes, hypertension, and dyslipidemia) can either improve ED or add to the efficacy of ED-specific therapies, e.g., PDE5 inhibitors. Level 1 evidence also exists that treatment of hypogonadism with total testosterone < 300 ng/dL (10.4 nmol/L) can either improve ED or add to the efficacy of PDE5 inhibitors. There is level 1 evidence regarding the efficacy and safety of the following monotherapies in a spectrum-wide range of ED populations: PDE5 inhibitors, intracavernosal injection therapy with prostaglandin E1 (PGE1, synonymous alprostadil) or vasoactive intestinal peptide (VIP)/phentolamine, and transurethral PGE1 therapy. There is level 2 evidence regarding the efficacy and safety of the following ED treatments: vacuum-erection therapy in a wide range of ED populations, oral L-arginine (3-5 g), topical PGE1 in special ED populations, intracavernosal injection therapy with papaverine/phentolamine (bimix), or papaverine/phentolamine/PGE1 (trimix) combination mixtures. There is level 3 evidence regarding the efficacy and safety of oral yohimbine in nonorganic ED. There is level 3 evidence that combination therapies of PDE5 inhibitors + either transurethral or intracavernosal injection therapy generate better efficacy rates than either monotherapy alone. There is level 4 evidence showing enhanced efficacy with the combination of vacuum-erection therapy + either PDE5 inhibitor or transurethral PGE1 or intracavernosal injection therapy. There is level 5 evidence (expert opinion) that combination therapy of PDE5 inhibitors + L-arginine or daily dosing of tadalafil + short-acting PDE5 inhibitors pro re nata may rescue PDE5 inhibitor monotherapy failures. There is level 5 evidence (expert opinion) that adding either PDE5 inhibitors or transurethral PGE1 may improve outcome of penile prosthetic surgery regarding soft (cold) glans syndrome. There is level 5 evidence (expert opinion) that the combination of PDE5 inhibitors and dapoxetine is effective and safe in patients suffering from both ED and premature ejaculation.

Cyclodextrin-based pharmaceutics: past, present and future

Cyclodextrins are cyclic oligomers of glucose that can form water-soluble inclusion complexes with small molecules and portions of large compounds. These biocompatible, cyclic oligosaccharides do not elicit immune responses and have low toxicities in animals and humans. Cyclodextrins are used in pharmaceutical applications for numerous purposes, including improving the bioavailability of drugs. Current cyclodextrin-based therapeutics are described and possible future applications discussed. Cyclodextrin-containing polymers are reviewed and their use in drug delivery presented. Of specific interest is the use of cyclodextrin-containing polymers to provide unique capabilities for the delivery of nucleic acids.

Long-term intracavernous therapy responders can potentially switch to sildenafil citrate after radical prostatectomy

OBJECTIVES

To assess whether long-term users of intracavernous (IC) injections after radical prostatectomy can switch to oral therapy with sildenafil citrate.

METHODS

Forty-nine patients (mean age 60.9 years) with erectile dysfunction after radical prostatectomy were identified as long-term users of IC injections (3.7 +/- 1.9 years). These patients received open-label treatment with sildenafil citrate (50 to 100 mg) for a minimum of 4 weeks or five attempts. The primary outcome measure of our study was assessed by the Sexual Health Inventory of Men (SHIM) questionnaire (International Index of Erectile Function-5 [IIEF]). A successful switch was prospectively defined as erection sufficient for vaginal penetration after sildenafil use and compliance to therapy. Patients were designated as responders or nonresponders on the basis of their ability to achieve vaginal penetration.

RESULTS

Of 49 patients, only 36 agreed to receive oral open-label sildenafil (50 to 100 mg) for a minimum of 4 weeks or five attempts. Prostaglandin E1 (PGE1) was used in 70% and triple therapy (PGE1, papaverine, and phentolamine) in the remaining 30%. Of the 36 patients, 15 (41%) successfully switched to sildenafil and discontinued IC injections. When the results were stratified by the type of IC solution, patients with high-dose triple therapy had a poor success rate of switch (7%) compared with patients using PGE1 treatment (67%). Of the 36 patients, 14 (38%) found sildenafil ineffective and continued using IC injections. Patients who switched to oral therapy had had a greater (P <0.001) total mean SHIM (IIEF-5) score with IC injections than those who did not switch (12.3 +/- 7.8 versus 20.0 +/- 4.9). Of the 36 patients, 7 (19%) found sildenafil alone to be suboptimal but continued using it, enhancing the efficacy of IC injections alone. The three predictive factors for a successful switch were high preoperative SHIM (IIEF-5) score, high post-IC injection SHIM score, and type of IC medication used (PGE1 alone versus high-dose triple therapy).

CONCLUSIONS

Long-term users of IC injection therapy can potentially switch to sildenafil citrate with acceptable sexual satisfaction. Patients will accept a lower degree of sexual satisfaction as measured by the IIEF-5 (SHIM) score if oral therapy is effective.

Prostaglandin E1 for treatment of erectile dysfunction

BACKGROUND

Erectile dysfunction (ED), the inability to achieve or maintain an erection sufficient for satisfactory sexual activity, is one of the most common sexual dysfunctions in men. ED may have a dramatic impact on the quality of life of many men and their partners.

OBJECTIVES

The aim of this systematic review was to evaluate and summarise the effectiveness and safety of PGE1 in the treatment of erectile dysfunction.

SEARCH STRATEGY

We searched the Cochrane MS Group Trials Register (June 2003), the Cochrane Central Register of Controlled Trials (issue 2, 2003), MEDLINE (January 1966 - June 2003), EMBASE (January 1988 - June 2003) and reference lists of articles. We also undertook handsearching and contacting trialists and pharmaceutical companies.

SELECTION CRITERIA

All unconfounded, double blind, randomised controlled trials comparing PGE1 and placebo treatment in participants with ED of different aetiology were considered. Primary outcomes were: (a) patient and partner satisfaction measured by means of a self-assessment; (b) quality of life and (c) safety assessment. Both parallel group and cross-over design trials were considered for inclusion.

DATA COLLECTION AND ANALYSIS

All the reviewers independently selected articles for inclusion, assessed the trials' quality and extracted the data. Study authors were contacted for additional information.

MAIN RESULTS

Four trials involving 1.873 people, heterogeneous with respect to aetiology of ED, were included. Study design was two cross-over and two parallel group trials. Only the latter provided adequate data for meta-analyses. PGE1 was effective during follow-up in the "at least one successful intercourse" outcome (Peto Odds Ratio, OR 7.22, 95% CI. 5.68-9.18) and "number of successful intercourse/number of PGE1 administrations" (Peto Odds Ratio, OR 6.46, 95% CI. 5.95-7.01). One cross-over study reported "at least one successful intercourse" in 63.6% of participants with at least one dose of PGE1 (P < 0.01 for each active dose versus placebo). In the other cross-over study, only one of three treatment groups conducted a self-evaluation (55.5%: "good" or "excellent" response). Adverse effects were most frequent in the treated groups and occurred more often and intensely as doses increased. Penile pain (Peto OR 7.39, 95% CI. 5.40-10.12) and minor urethral trauma (Peto OR 3.79, 95% CI. 1.88-7.65) were predominant.

REVIEWERS' CONCLUSIONS

PGE1 was beneficial for many participants with ED of different aetiology. Adverse effects were proportional to dosage, albeit never serious. The use of PGE1 in ED could have been better interpreted if its effectiveness were compared by aetiology and with different forms of administrations, a longer follow-up were considered and more emphasis given to patient/partner relationships and quality of life.

Long-term efficacy and compliance of intracorporeal (IC) injection for erectile dysfunction following radical prostatectomy: SHIM (IIEF-5) analysis

Baseline and follow-up data from 102 patients using intracorporeal (IC) injection for erectile dysfunction (ED) following RP were retrospectively collected. We compared baseline International Index for Erectile Function (IIEF) questionnaires with the abridged IIEF-5 questionnaires, referred to as the Sexual Health Inventory of Men (SHIM) to determine drug efficacy. The mean presurgery SHIM score was 21.75+/-5.23, which decreased to 4.23+/-3.48 after surgery and increased to 19.46+/-8.78 post-treatment. Overall, 68% (69/102) of patients achieved and maintained erections sufficient for sexual intercourse and 48% (49/102) of patients continued long-term therapy with a mean use of 3.7+/-1.9 y. In all, 52% (53/102) patients discontinued IC therapy. However when excluding patients who switched to oral therapy, had loss of partner or return of normal erections; the compliance to IC injections was 70.6% (71/102). There was no difference in the SHIM analysis between the nerve sparing (NS) and the non-NS or between the types of medications used. IC injections can provide excellent long-term efficacy and compliance in up to 70% of the patients. This study suggests that IC injections are an excellent salvage option in NS patients who fail oral therapy and a first option in patients with non-NS procedures.

Enhancement of apomorphine-induced penile erection in the rat by a selective alpha(1D)-adrenoceptor antagonist

1. Effects of A-322312 (alpha(1B)-adrenoceptor (AR) antagonist), A-119637 (alpha(1D)-AR antagonist), prazosin (non-selective alpha(1)-AR antagonist), and yohimbine (alpha(2)-AR antagonist) were studied in rat corpus cavernosum (CC) and cavernous artery (Acc) preparations. Effects of intracavernous (i.c.) or intraperitoneal (i.p.) administration of alpha(1)-AR antagonists on apomorphine-induced erections were investigated. 2. A-119637 attenuated electrically induced contractions in isolated CC (-logIC(50); 8.12+/-0.15), and relaxed noradrenaline (NA)-contracted preparations by more than 90% at 10(-7) M. At the same concentration, the -logEC(50) value for NA in Acc was altered from 6.79+/-0.07 to 4.86+/-0.13. In the CC and Acc, prazosin similarly inhibited contractile responses. 3. Inhibitory effects of A-322312 (10(-7) M) in electrically activated CC were 32.3+/-5.1%, whereas no effect on concentration-response curves for NA was observed in the Acc. Yohimbine (10(-8) M and 10(-7) M), enhanced electrically-induced contractions in isolated CC by 20 to 50%. At 10(-6) M, inhibitory effects of yohimbine were obtained. 4. A-119637 (0.3 micromol kg(-1), i.p.) tripled the number of erections, and produced a 6 fold increase in the duration of apomorphine-induced erectile responses. A-322312, prazosin, or yohimbine did not enhance erections induced by apomorphine. None of the alpha(1)-AR antagonists significantly increased ICP upon i.c. administration. Decreases in blood pressure were seen with A-119637 and prazosin. 5. The present findings show that there is a functional predominance of the alpha(1D)-AR subtype in the rat erectile tissue, and that blockade of this receptor facilitates rat penile erection induced by a suboptimal dose of apomorphine.

Interactions between drugs for erectile dysfunction and drugs for cardiovascular disease

The association of erectile dysfunction (ED) and cardiovascular disease is well-documented in the literature and both conditions share risk factors. Therefore, it is difficult to distinguish the effect of underlying disease and adverse effects of the drugs and/or interactions between ED drugs and drugs implemented for cardiovascular disease. The known interactions of systemic administered drugs for ED with drugs for cardiovascular disease are mainly pharmacodynamic. Thus, nitrates enhance the production of cyclic GMP and combined with phosphodiesterase type-5 inhibitors this can lead to severe hypotension. The same is the case for the treatment with phentolamine in patients treated with beta-adrenoceptor antagonists. Due to increased partial thromboplastin time, the risk of bleeding is enhanced for intracavernous alprostadil injection in heparin-treated patients. Pharmacokinetic interactions of clinical importance have been described for ED drugs with other therapeutic groups such as sildenafil with the antifungal drug, ketoconazole, and apomorphine with the antiparkinson drug, entacapon. Although sildenafil and antihypertensive dihydropyridines like amlodipine are metabolized by the same cytochrome P450 enzyme, CYP3A4 in the liver, the combination of these drugs does not exhibit a synergistic blood pressure lowering action. Unfortunately documentation concerning drug interactions is often poor and occasional.

Intracavernosal therapy: when oral agents fail

Erectile dysfunction is a common problem in men older than 40 years, and the incidence increases markedly with age. Approximately one fourth of impotent men use intracavernosal injections as a primary treatment. Since its original description in the early 1980s, injection therapy has been used safely and successfully by many men and their partners. Intraurethral and oral agents for the treatment of erectile dysfunction have been introduced over the last few years, but early reports of patient satisfaction and reproducibility of erectile rigidity have not matched those of intracavernosal therapy. Thus, injection therapy remains on the forefront of treatment options.

A risk-benefit assessment of sildenafil in the treatment of erectile dysfunction

Sildenafil is an oral treatment for erectile dysfunction (ED). It acts as an inhibitor of 3',5'-cyclic guanosine monophosphate-phosphodiesterase type 5. An effective treatment for ED is required to produce an erectile response sufficient for satisfactory sexual performance. This has been documented for sildenafil in men with ED of differing aetiologies and baseline severity in various types of clinical trials. Sildenafil treatment is characterised by a good tolerability profile and low treatment digcontinuation rate caused by treatment-related adverse effects. Most of the adverse effects associated with sildenafil are extensions of the pharmacological action of the drug. There is no significant difference in the adverse effect profile (headache, flushing, dyspepsia, nasal congestion and abnormal vision) of this agent as assessed by clinical data obtained either in the pre- and postlaunch periods. Because of its acceptable risk-benefit ratio, sildenafil can be prescribed to a very large group of patients with ED. The reports of serious cardiovascular events associated with the use of sildenafil (including anecdotal reports of deaths) have been very thoroughly analysed. A number of studies have not shown any difference in the risk of serious cardiovascular events in sildenafil- and placebo-treated patients. However, when making a risk-benefit evaluation, certain subgroups of patients need to be considered separately. In particular, sildenafil is contraindicated in patients receiving nitrate therapy. In some other subgroups of patients, the risks and benefits of treatment need to be assessed on an individual basis and it is hoped that additional data will clarify any possible risks associated with sildenafil administration such patients. It is helpful to compare the risk-benefit profile of sildenafil with the characteristics of other oral drugs for ED. According to the preliminary data, apomorphine and phentolamine are possible future options for the treatment of ED; however, there needs to be further clinical evaluation of these agents. Initial data have shown that sildenafil can be successfully combined with intracavernosal injection in patients nonresponders to either therapy. In conclusion, favourable characteristics make sildenafil suitable for the first-line therapy for a substantial proportion of patients with ED.

Oral and injectable medications for the treatment of erectile dysfunction

The treatment of erectile dysfunction has changed dramatically over the past two decades. The introduction of the oral agent sildenafil 2 years ago has revolutionized the treatment of men with compromised erections and has met with expected success and low morbidity. Sildenafil is effective in most men with erectile dysfunction in the general population and in select populations, such as men with spinal cord injury, diabetes mellitus, and patients who have had nerve-sparing radical prostatectomy. It is safe in the general population as well as in many men with cardiac disease. Other newer medications are in trial and may soon be available to supplement treatment with sildenafil. Oral phentolamine, apomorphine, newer phosphodiesterase type-5 inhibitors, and topical agents are currently in phase 3 trials. These agents, in addition to newer intraurethral and indictable agents, may assist men with erectile dysfunction and rescue those in whom sildenafil is ineffective or in whom untoward side effects of sildenafil reduce its effectiveness. The 21st century will witness many additional agents designed for specific patients with specific conditions causing erectile dysfunction. We can expect these oral agents, assisted by topical and injectable agents, to successfully restore erectile function in the majority of men suffering from erectile dysfunction.

Non-surgical management of erectile dysfunction

Erectile dysfunction is a common and distressing medical condition that is now highly amenable to treatment almost irrespective of the cause. Safe, non-surgical treatments with unequivocal efficacy are psychological therapy, intracorporeal injection of vasoactive drugs, transurethral vasodilators and oral sildenafil, all of which have been reported to have a 50-70% overall response rate. Vacuum constriction devices are acceptable for some, usually older patients and oral yohimbine is thought to have marginal efficacy. Local creams to induce or enhance erectile function are currently being investigated. There is no place for androgen supplementation unless the patient is profoundly hypogonadal. Treatment of hyperprolactinaemia is very effective but is a rare cause of erectile dysfunction. As intercourse may entail an unfamiliar level of physical activity, it is sensible to ensure that the patient is able to climb a flight or two of stairs comfortably without provoking undue breathlessness or chest pain and to provide suitable advice about technique before commencing treatment. Once it is clear to the patients that erectile dysfunction can be satisfactorily overcome, the long-term use of treatments to do so tends to wane. Thus, although the prospect of effective treatment for what had been for many a distressing life sentence has the potential to place new demands on the health service, there is no evidence that restrictions on prescribing will prove economically rational.

Intracavernous alprostadil alfadex is more efficacious, better tolerated, and preferred over intraurethral alprostadil plus optional actis: a comparative, randomized, crossover, multicenter study

OBJECTIVES

To compare the efficacy, safety, and patient preference of intracavernously administered alprostadil alfadex and intraurethrally administered alprostadil.

METHODS

A crossover, randomized, open-label multicenter study of 111 patients with erectile dysfunction of at least 6 months' duration compared the efficacy, safety, and patient preference of intracavernosal alprostadil (EDEX/Viridal) with MUSE plus optional ACTIS. All patients underwent an in-office dose titration with either drug before undertaking an at-home treatment phase. The most frequently used doses during the at-home phase were 40 microg (44.1% of men) and 1000 microg (86.8% of men) for EDEX and MUSE, respectively; the mean doses were 26.1 microg and 922.5 microg for EDEX and MUSE, respectively.

RESULTS

More EDEX than MUSE administrations resulted in an erection sufficient for sexual intercourse (82.5% versus 53.0%); significantly more patients using EDEX achieved at least one erection sufficient for sexual intercourse (92.6% versus 61.8%; P <0.0001); and EDEX use resulted in a significantly greater percentage of patients attaining at least 75% of erections sufficient for sexual intercourse (75% versus 36.8%; P <0.0001). Penile pain was the most common side effect for both medications: 20.0% versus 30.5% (in-office) and 33.8% versus 25.0% (at-home) for EDEX and MUSE, respectively. Similar numbers of adverse events were reported with either treatment during the at-home phase. Patient and partner satisfaction was greater with EDEX, and more patients preferred this therapy, choosing to continue it during a patient preference period at the end of the study.

CONCLUSIONS

Since intracavernous injection therapy was more efficacious, better tolerated, and preferred by the patients and their partners, it should be offered as the first-choice treatment if oral therapy fails or is contraindicated.

Pharmacotherapeutic advances in the treatment of erectile dysfunction

An estimated 20 million to 30 million American men have erectile dysfunction (ED). The past 2 decades of research defining erectile physiology and investigating the pathogenesis of ED have led to the recognition of a predominantly vascular basis for organic male sexual dysfunction. These scientific advances have laid the foundation for the advent of pharmacotherapies. The Food and Drug Administration approval of intracavernosal, intraurethral, and oral pharmacotherapeutics for ED has revolutionized non-surgical management of this condition. The primary care physician is faced with the challenges of diagnosis and treatment of ED, as well as referral of patients to urologists. In this article, erectile physiology and pathophysiology are reviewed, and pharmacotherapeutics are classified and discussed by their mechanisms of action and the means of administration. A thorough understanding of these new therapeutic options is key to the accurate diagnosis and successful treatment of ED and maximal patient satisfaction and care.