Combination therapy for erectile dysfunction: a randomized, double blind, unblinded active-controlled, cross-over study of the pharmacodynamics and safety of combined oral formulations of apomorphine hydrochloride, phentolamine mesylate and papaverine hydrochloride in men with moderate to severe erectile dysfunction

Oral therapy has become first line treatment for patients with mild to moderate erectile dysfunction (ED). Studies have shown that sildenafil may not be effective in all patients, and has been associated with a variety of adverse effects and an adverse interaction with nitrates and inhibitors of cytochrome P450 enzymes. The objective was to compare the efficacy and safety of three different oral combinations with the highest dose of sildenafil in men with moderate to severe ED. Randomized, double blind, unblinded active-controlled, Phase II study was carried out at three sites in Mexico. After a 4-week placebo run-in period, patients received all four of the following treatments using a 4-way cross-over design: 40 mg phentolamine (PM) +6 mg apomorphine (Apo); 40 mg PM +150 mg papaverine (Pap); 40 mg PM +6 mg Apo +150 mg Pap (Tricombo); 100 mg sildenafil (SC). With the exception of sildenafil tablets, all study medication was blinded. Moderate to severe ED was defined as a less than 50% vaginal penetration success rate during the placebo run-in period. A total of 44 patients were enrolled, of whom 36 completed all four treatment periods. All treatments produced a significant effect in primary efficacy variable (Sexual Encounter Profile) compared to baseline, however, no statistically significant differences were found between treatments. A significant period effect was observed. Also, the four treatments were found not to differ significantly in five out of six secondary efficacy variables. The lowest incidence of treatment-related adverse events (AE) occurred in the 40 mg PM +6 mg Apo group (9.8%), followed by 100 mg SC (15%), and the other two combinations (16.7 and 17.5%, respectively). Nasocongestion and headache were the most frequently reported AE. An oral combination of vasoactive agents may provide an alternative approach to sildenafil. Based on these results a combination of phentolamine and apomorphine warrants further clinical investigation.     

A European multicentre study to evaluate the tolerability of apomorphine sublingual administered in a forced dose-escalation regimen in patients with erectile dysfunction

OBJECTIVE: To determine the risk-benefit ratio of a forced dose-escalation regimen (2 to 3 to 4 mg) in a European clinical study evaluating apomorphine sublingual (SL) in treating erectile dysfunction (ED), by evaluating the overall tolerability and efficacy of the regimen compared with placebo in patients with ED, and evaluating efficacy by assessing the proportion of successful attempts resulting in sexual intercourse. PATIENTS AND METHODS: This randomized, double-blind, two-arm, parallel-group study was conducted in 507 patients enrolled at 34 European sites. After a 1-2 week screening period, patients were treated for 8 weeks with either placebo or apomorphine SL administered as a forced dose-escalation regimen. Heterosexual men (aged 18-70 years) were eligible for participation in the study if they were in stable health, a stable relationship of > or = 6 months duration, had a history of erectile inability, and were diagnosed with ED (successful in fewer than half of attempts to attain and maintain an erection firm enough for intercourse during the 30 days before screening). Patients provided information (recorded on diary cards and reviewed at each study visit) about the frequency and success in achieving erections and of sexual intercourse attempts during both the screening and treatment periods. The dosing regimen required patients to take one tablet of apomorphine SL (2 mg for 2 weeks, then 3 mg for 2 weeks and finally 4 mg for the remaining 4 weeks) or placebo 15-25 min before intercourse, and intercourse was to be attempted at least twice a week. Safety data were collected throughout the 8-week study period, and included recording adverse events, vital signs and changes in laboratory test values for standard haematology and biochemistry variables. The primary efficacy variable was the proportion of successful attempts, defined as an erection rigid enough for sexual intercourse, occurring after dosing (successful intercourse rate). The proportion of erections achieved was a secondary efficacy variable. RESULTS: Of the 507 patients, 254 received apomorphine SL and 253 received placebo; 87% of patients in both groups completed the 8-week treatment period. Of the patients receiving apomorphine SL, 24% had hypertension, 11% had coronary artery disease, 10% had diabetes, and 5.5% had benign prostatic hypertrophy; 62.6% of treated patients received concomitant medications for these maladies. The treatment groups were balanced for demographic and baseline variables, including comorbidity factors. Treatment-emergent adverse events, reported by > 5% of patients in the treated group, were nausea (9.8%), dizziness (7.1%) and headache (6.7%), compared with 0.4%, 2.4% and 4.0%, respectively, in the placebo group. Sixty-six patients withdrew from the study, 16 because of study drug-related adverse events (12 from the apomorphine and four from the placebo group). Six patients (three in each group) reported a total of nine serious treatment-emergent adverse events, all of which resolved by the end of the study. In the intention-to-treat population, the proportion of successful attempts at sexual intercourse and of erections were statistically greater in the apomorphine than in the placebo group (P = 0.001 and 0.021, respectively); analysis of the per-protocol population results confirmed this significant difference. CONCLUSION: This European study supports the safety and tolerability of apomorphine SL despite the forced escalation to a 4-mg dose (exceeding the approved 2-3 mg dose). Adverse effects were not treatment-limiting. These results further support the clinically significant efficacy of apomorphine SL for treating ED at all doses used. The risk/benefit ratio supports apomorphine SL as a safe and effective alternative in managing ED.     

Post-marketing surveillance study of the safety and efficacy of sildenafil prescribed in primary care to erectile dysfunction patients

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.     

Comparative cross-over study of sildenafil and apomorphine for treating erectile dysfunction

OBJECTIVE

To compare the effectiveness, safety and tolerability of sildenafil and apomorphine in Brazilian patients with erectile dysfunction (ED) of various causes.

PATIENTS AND METHODS

In all, 108 patients (mean age 55 years, sd 11) and documented ED for ≥6 months were included in 12 centres in Brazil. The patients were initially followed for 2 weeks and then randomized to initial treatment with apomorphine or sildenafil, taken before sexual intercourse, no more than once a day. The initial dose (2 mg apomorphine and 50 mg sildenafil) could be adjusted (to 3 mg apomorphine, or to 25 or 100 mg for sildenafil) depending on the effectiveness and tolerability during the first 4 weeks of treatment. The patients were re‐evaluated after 8 weeks on treatment and, after a wash‐out period of 2 weeks (no treatment), received the other study drug (other than that received in the first phase), and then had the same procedures as in the first phase.

RESULTS

In all, 97 patients were evaluated for therapeutic effectiveness, the overall effectiveness being assessed using two questions; sildenafil had a significantly higher proportion of affirmative answers for both (P < 0.001). Likewise, the estimates for the mean (sd ) proportion of successful sexual intercourse, of 83.3 (4.7)% vs 40.3 (4.7)% and the total ED Inventory of Treatment Satisfaction score, of 86.7 (2.9) vs 56.9 (2.9) (P < 0.001) were higher for sildenafil. At the end of the study, 93.8% of the patients randomized to initial therapy with apomorphine declared a preference for sildenafil, and 81.3% of those initially treated with sildenafil declared a preference for that drug. The two drugs were well tolerated, and the main adverse events for apomorphine were nausea, vomiting, headache, taste perversion and dizziness; for sildenafil they were headache, flushing or vasodilatation, abdominal pain or dyspepsia and nasal congestion.

CONCLUSIONS

Sildenafil is more effective than apomorphine for treating ED, in the domains of erectile function, satisfaction with sexual intercourse and overall satisfaction, and was the drug preferred by most of the patients.     

Double-blind, crossover comparison of 3 mg apomorphine SL with placebo and with 4 mg apomorphine SL in male erectile dysfunction.

OBJECTIVE: To establish the efficacy and safety of a fixed, 3-mg dose of apomorphine SL compared with placebo, and to compare 3 mg with 4 mg apomorphine SL in patients with erectile dysfunction. METHODS: This randomized, double-blind, crossover study included 296 heterosexual men with ED of various etiologies and severities. Two crossover groups were evaluated separately: 3 mg apomorphine SL vs. placebo (n = 194), and 3 vs. 4 mg apomorphine SL (n = 102). The primary efficacy variable was the percentage of attempts resulting in erections firm enough for intercourse; additional variables included the percentage of attempts resulting in intercourse and time to erection. Partner assessments were also analyzed. RESULTS: 3 mg apomorphine SL was significantly more effective than placebo (p<0.001) for the percentage of attempts resulting in erections firm enough for intercourse and resulting in intercourse, as assessed by both patients and partners. Median time to erection was 18.8 min. The 3-mg dose was not significantly different from 4 mg in the evaluation of efficacy variables, but the incidence of adverse events was higher with 4 mg. Nausea was the most common event, reported by 3.3% of patients on 3 mg vs. 14.1% on 4 mg; in the placebo comparison, nausea was reported by 7.0% of patients taking 3 mg apomorphine SL vs. 1.1% of those taking placebo. CONCLUSIONS: 3 mg apomorphine SL was significantly more effective than placebo and comparable to 4 mg, while offering an improved risk-benefit ratio.     

Medication prescribing patterns in ambulatory haemodialysis patients: comparisons of USRDS to a large not-for-profit dialysis provider.

BACKGROUND: End-stage renal disease (ESRD) patients are prescribed numerous medications. The United States Renal Data System (USRDS) reported on medication prescribing patterns in 1998. Since then, several new medications, treatment guidelines and recommendations have been introduced. The objective was to analyse and compare haemodialysis (HD) patient medication prescribing patterns between the Dialysis Clinic, Inc. (DCI) database and the USRDS report. METHODS: Point-prevalent (01/01/03) medication use data from the DCI national database was obtained. Data collected included patient demographics, reason for and duration of ESRD, and medication listed on profile. All medications were classified similar to the USRDS and by where taken (clinic vs home). Medication prescribing patterns were compared between DCI and USRDS databases. Comparisons between age groups (<65 and >or=65 years) and diabetic status [diabetes mellitus (DM) vs non-DM] were made. RESULTS: There were 128 477 medication orders categorized in 10 474 patients. DCI patient demographics were similar to present USRDS patients except for fewer Hispanics (P<0.001). Patients were prescribed 12.3+/-5.0 (median 12) different medications (2.6+/-1.4 clinic medications and 10.0+/-4.5 home medications). This is higher than reported by USRDS (median 9 medications). Patient age did not influence number of medications used (P = 0.54). DM patients are prescribed more medications than non-DM (13.3+/-5.0 DM vs 11.6+/-4.8 non-DM; P<0.00001). All medication class prescribing patterns were markedly different. CONCLUSION: The data suggest that medication prescribing patterns in HD patients have changed. The audit identified appropriate and questionable prescribing patterns. Various prescribing patterns identified areas for improvement in care (e.g. increased use of aspirin, beta-blockers and hyperlipidaemia medications) and areas requiring further investigation (e.g. high use of anti-acid, benzodiazepine and non-aluminum/non-calcium phosphate-binding medications).     

A comparative, crossover study of the efficacy and safety of sildenafil and apomorphine in men with evidence of arteriogenic erectile dysfunction

The aim of the study was to establish and compare the efficacy and safety of sildenafil and apomorphine in men with arteriogenic erectile dysfunction (ED). In all, 43 men with ED and postinjection max penile systolic velocity <25 cm/s in repeated Doppler ultrasonography were included. Of these, 24 men started on apomorphine 2 mg and 19 on sildenafil 50 mg, the doses titrated up to 3 and 100 mg according to effectiveness and tolerability. Safety was evaluated according to adverse events (AEs) and patient withdrawal. Efficacy was the percentage of attempts resulting in erections firm enough for intercourse, based on event log data. The incidence of AEs with apomorphine 3 mg was higher than with sildenafil 100 mg. Two men on apomorphine 3 mg discontinued treatment due to AEs. The overall success rate of sildenafil was 63.7% compared to 32.1% of apomorphine (Pearson chi(2), P<0.01). Of all men, 25 (58.1%) responded to sildenafil 50 mg without the need for dose increase, while only one responded to apomorphine 2 mg. The response to sildenafil 50 mg was age related (analysis of variance, p=0.04). Satisfaction was reported by 76.75 and 13.95% of patients for sildenafil and apomorphine, respectively, but 20.9% were not satisfied with any of the two drugs. In conclusion, this study provides clear evidence that sildenafil, even at 50 mg dose, is more effective than apomorphine 3 mg in men with arteriogenic ED. The fact that one out of five patients is not satisfied with the above-studied drugs shows that new oral agents need to be evaluated for the treatment of this disorder.