西地那非治疗保留神经耻骨后前列腺根治性切除术后ED

耻骨后前列腺根治术对患者性功能会产生不同程度的影响,可引起勃起功能障碍(ED)。治疗ED的一线口服药西地那非对此类人群是否有效呢?Shimizu T等人回顾性评价了保留神经耻骨后前列腺根治性切除术(RRP)后的勃起功能,以及西地那非治疗RRP后ED的疗效。1996年1月到2001年12月,研究者利用专为本研究设计的问卷,对48例接受保留神经耻骨后前列腺     

西地那非治疗根治性前列腺切除术后ED的结果及预测因子

勃起功能障碍（ED）是根治性前列腺切除术后不希望发生的一种并发症，但是它的发生率又非常高（10—90）％。西地那非治疗ED的有效性已有相关研究。为确定根治性前列腺切除术后使用西地那非治疗的结果和预测因子，Lima Pompeo AC等进行了一项研究。入选了71例临床局限性前列腺癌患者（平均65岁），行耻骨后前列腺癌根治术，术前有良好性交能力。其中61例患者在手术过程中保留了单侧或双侧的性神经。术后3-28个月中，主诉有勃起功能障碍的患者，以不能插入阴道确定。这些患者口服西地那非100mg，     

伐地那非治疗耻骨后前列腺根治切除术后的勃起功能障碍

超过三分之一的患者在行保留性神经的前列腺根治切除术后会出现勃起功能障碍(ED)。最近的研究表明,磷酸二酯酶 5(PDE5)抑制剂伐地那非可改善保留单侧或双侧神经的耻骨后前列腺根治切除术后ED患者的勃起功能,而且安全性良好。     

伐地那非对肾阳虚、肾阴虚及肝气郁结型勃起功能障碍的疗效分析

目的:观察伐地那非对肾阳虚、肾阴虚及肝气郁结型勃起功能障碍(ED)的临床疗效。方法:将124例ED患者按中医辨证分为肾阳虚型ED(44例)、肾阴虚型ED(41例)、肝气郁结型ED(39例),所有患者每天服用伐地那非5 mg,总疗程为8周。结果:伐地那非能显著提高各型ED患者的勃起功能问卷-5(IIEF-5)和勃起质量表(EQS)评分,且各组间比较差别有统计学意义(P<0.01);伐地那非显著提高肾阳虚和肾阴虚型ED患者性交成功百分率(P<0.01),肝气郁结型ED在治疗后性交成功百分率也有明显提高(P<0.05);伐地那非还能显著提高各型ED患者阴茎勃起硬度,3组治疗后总体有效率分别为81.82%、73.17%、43.59%。结论:伐地那非对肾阳虚和肾阴虚型ED患者疗效优于肝气郁结型ED患者。     

伐地那非治疗难治性勃起功能障碍的最新进展

5型磷酸二酯酶(phosphodiesterase 5,PDE5)在阴茎勃起功能中所起的作用越来越引起人们的关注。环磷酸鸟苷(cGMP)信号通路介导的一氧化氮平滑肌舒张效应是正常勃起功能的必要条件,这个信号通路的下调能引起勃起功能障碍(erectile dysfunction,ED)的许多病理状态,并导致一些慢性疾病的发生。本文回顾了伐地那非治疗ED患者的有效性和安全性。结果表明,伐地那非对于合并异常脂蛋白血症和高血压、糖尿病、抑郁症、前列腺切除术后、外伤性脊髓损伤、西地那非治疗无效、肾移植术后、慢性前列腺炎和早泄的ED患者安全有效,为这些难治性ED患者提供了一种合理的治疗选择。另外,伐地那非还能延长ED患者的勃起时间。     

全面康复:勃起功能障碍治疗的新目标

5型磷酸二酯酶(PDE5)抑制剂有效改善勃起功能障碍(ED)患者的勃起功能。枸橼酸西地那非的应用范围不断扩展,肺动脉高压已成为新的适应证。临床研究发现,西地那非能改善多种血管性疾病患者的内皮功能。在ED领域的研究进展包括:动物实验发现,西地那非可以改善海绵体内皮功能,增强磷酸化内皮型一氧化氮合酶(eNOS)蛋白表达,逆转缺血或缺氧导致的海绵体内压(ICP)降低。临床研究证实,西地那非可以使50%以上ED患者阴茎勃起恢复到最充分的硬度(4级勃起);使50%以上保留神经的根治性前列腺切除术后患者勃起功能康复,自发产生足以性交的勃起;使ED患者的自尊心、自信心和性关系满意度等社会心理功能恢复正常。从勃起功能到社会心理功能的全面恢复可能成为今后ED治疗的新目标。     

关于CONFIRMED研究中伐地那非与西地那非临床疗效的比较

CONFIRMED研究是完全遵循良好试验设计规范进行设计的一项研究。该研究是一项非劣性设计,主要目的是比较伐地那非与西地那非在治疗男性勃起功能障碍(ED)方面患者选择的倾向性,结果表明,总体倾向性伐地那非优于西地那非,尤其在总体满意度、性交满意度及伴侣关系满意度等方面显著优于西地那非。通过比较伐地那非与西地那非的结构,伐地那非的结构更具优势,其5型磷酸二酯酶(PDE5)选择性远远高于西地那非,这是伐地那非临床疗效优于西地那非的分子学基础。本研究提供了伐地那非优于西地那非的临床证据,进一步证实了伐地那非是对ED患者进行治疗的一线药物。     

5型磷酸二酯酶抑制剂治疗辅助生殖技术中偶发ED

目的:探讨5型磷酸二酯酶抑制剂(PDE5i)对辅助生殖技术(ART)中偶发阴茎勃起功能障碍(ED)的治疗价值。方法:2008年3月至2012年6月行ART治疗的因偶发性ED而发生取精困难的患者75例,给予口服PDE5i(西地那非、他达拉非、伐地那非)的方法进行治疗,采用勃起硬度分级(EHS)法对患者的勃起程度进行评价,对患者获取精液的成功率进行分析。结果:75例患者中,有28例、25例和22例分别服用西地那非、他达拉非和伐地那非,61例(81.3%)服药后有效勃起,其中西地那非24例,他达拉非20例,伐地那非17例,有效率分别为85.7%、80.0%和77.3%,三者比较差异无统计学意义(P>0.05)。75例患者中有53例(70.7%)服药后有效勃起并成功获取精液,其中西地那非21例,他达拉非17例,伐地那非15例,成功率分别为75.0%、68.0%和68.2%,三者比较差异无统计学意义(P>0.05)。75例患者中有37例和38例分别服用PDE5i一般推荐剂量(半量)和最大推荐剂量(全量),分别有28例和25例获取精液成功,成功率分别为75.7%和65.8%,两者相比差异无统计学意义(P>0.05)。75例患者中有5例(6.7%)服药后出现轻度一过性的颜面潮红、头晕等药物不良反应。结论:3种PDE5i均能帮助偶发性ED患者有效勃起并成功获取精液,是治疗ART中突发性取精困难患者的一种安全有效的药物。     

西地那非治疗根治性前列腺切除术后勃起功能障碍

前列腺根治术是治疗前列腺癌的常用方法,术后部分患者会发生勃起功能障碍(ED)。Zippe等进行了一项研究,探讨了前列腺癌根治术后ED患者对西地那非的反映是否受神经血管束的存在与否、手术到用药的时间间隔、药物剂量等因素的影响。他们研究了91例前列腺根治性切除术后ED患者的基     

应用西地那非治疗前列腺根治术后勃起功能障碍的有效性及预后良好相关因子的研究

前列腺根治术(RP)是治疗前列腺癌的有效方法,但手术可能影响患者的性功能而出现勃起功能障碍(ED)。枸橼酸西地那非对于多种病因的ED都有效,那么该药对前列腺根治术后的ED患者是否有效以及影响疗效的因素又有那些呢?Raina R等人对此进行了相关研究[Urology,2004,63(5):960-966]。他们入选了平均年龄(60.1±6.25)岁的174例分别接受保留双侧神经(59.8%)、保留单侧神经(16.1%)和未保留神经(24.1%)的RP术并出现ED的患者,所有患者服用枸橼酸西地那非治疗,初始剂量为50mg,若无效增加为100mg。从RP到此次用药的间期为3个月。在治疗前和治疗1…     

Tadalafil in the treatment of erectile dysfunction following bilateral nerve sparing radical retropubic prostatectomy: a randomized, double-blind, placebo controlled trial

PURPOSE: We evaluated the efficacy and safety of tadalafil 20 mg, taken on demand, in men with erectile dysfunction following bilateral nerve sparing radical retropubic prostatectomy (BNSRRP). MATERIALS AND METHODS: This randomized, double-blind, placebo controlled multicenter study consisted of a 4-week treatment-free run-in period (baseline) followed by 12 weeks of treatment. A total of 303 men (mean age 60 years) with preoperative normal erectile function who had undergone a BNSRRP 12 to 48 months before study were randomized (2:1) to tadalafil (201) or placebo (102). The 3 co-primary end points were changes from baseline in the International Index of Erectile Function erectile function domain score, and the percentage of positive responses to Sexual Encounter Profile questions 2 (successful penetration) and 3 (successful intercourse). The Global Assessment Question and the Erectile Dysfunction Inventory of Treatment Satisfaction questionnaire were secondary end points. We defined a priori a subgroup of 201 patients reporting evidence of postoperative tumescence, defined as 50% or greater "yes" responses to Sexual Encounter Profile question 1 (ability to achieve at least some erection) during baseline intercourse attempts and stratified randomization based on this criterion. RESULTS: Patients receiving tadalafil reported greater improvement on all primary and secondary end points (p <0.001) compared to placebo. For all randomized patients and for the subgroup with evidence of postoperative tumescence, the mean International Index of Erectile Function erectile function domain score increased for patients receiving tadalafil (mean +/- SEM 5.3 +/- 0.5 and 5.9 +/- 0.7, respectively, p <0.001 vs placebo for both). For all randomized patients who received tadalafil, the mean percentage of successful penetration attempts was 54% and the mean percentage of successful intercourse attempts was 41%. For the subgroup with evidence of postoperative tumescence these values were 69% and 52%, respectively. Of all patients randomized to tadalafil 62% and of the subgroup patients randomized to tadalafil 71% reported improved erections. Patients receiving tadalafil reported greater treatment satisfaction on the Erectile Dysfunction Inventory of Treatment Satisfaction than those receiving placebo. Headache (21%), dyspepsia (13%) and myalgia (7%) were the most commonly reported adverse events. CONCLUSIONS: Tadalafil 20 mg, taken on-demand, was an efficacious and well tolerated treatment for erectile dysfunction following BNSRRP.     

Treatment of erectile dysfunction after radical prostatectomy with sildenafil citrate (Viagra)

Objectives. To determine whether the response to the new oral medication, sildenafil citrate (Viagra), was influenced by the presence or absence of the neurovascular bundles, as recent reports on its success did not specify the efficacy of the drug in patients with erectile dysfunction after radical prostatectomy.Methods. Baseline and follow-up data from 28 healthy patients presenting with erectile dysfunction after radical prostatectomy were obtained. Patients receiving any neoadjuvant/adjuvant hormones or adjuvant radiation therapy were excluded. Patients reported what their erectile status was before surgery, before sildenafil therapy, and after using a minimum of four doses of sildenafil. Both the patients and their spouses were interviewed using the Cleveland Clinic post-prostatectomy questionnaire, which includes questions about response to therapy, duration of intercourse, spousal satisfaction, side effects, and related topics. The patients were compared on the basis of the type of surgical procedure they had undergone—nerve sparing or non-nerve sparing. A positive response to sildenafil was defined as erection sufficient for vaginal penetration.Results. Of the 15 patients who had bilateral nerve-sparing procedures, 12 (80%) had a positive response to sildenafil, with a mean duration of 6.92 minutes of vaginal intercourse. These 12 patients also reported a spousal satisfaction rate of 80%. All 12 of the responders had a positive response within the first three doses, and 10 of the 12 responded with the first or second dose. None of the 3 patients who had undergone a unilateral nerve-sparing procedure responded, nor did any of the 10 patients who had undergone a non-nerve-sparing procedure. The two most common side effects of the drug were transient headaches (39%) and abnormal color vision (11%). No patients discontinued the medication because of side effects.Conclusions. Successful treatment of erectile dysfunction in a patient after prostatectomy with sildenafil citrate may depend on the presence of bilateral neurovascular bundles. No patient who had undergone a non-nerve-sparing procedure responded. Whether patients who undergo unilateral nerve-sparing procedures will respond to sildenafil is still unclear because of the small number of patients in our study. These findings should encourage urologists to continue to perform and perfect the nerve-sparing approach. The ability to restore potency with an oral medication after radical prostatectomy will impact our discussion with the patient on the surgical morbidity of radical prostatectomy.     

Role of sildenafil citrate in treatment of erectile dysfunction after radical retropubic prostatectomy

BACKGROUND: Sildenafil citrate was introduced as a treatment for erectile dysfunction in April 1998 in the United States and has been available since March 1999 in Japan. In this article, we assess the efficacy of sildenafil in the treatment of erectile dysfunction in Japanese men after radical retropubic prostatectomy for localized prostate cancer. METHODS: Of 106 men who underwent radical retropubic prostatectomy between January 1994 and March 2000, 43 were prescribed sildenafil at their request after radical retropubic prostatectomy. Medication was initiated at 25 mg, and if this was ineffective, the dose was increased to 50 mg. Of the patients, 18 underwent bilateral and 21 unilateral nerve sparing (NS) procedures, while in 4 patients, a non-NS procedure was performed. These patients were interviewed using a questionnaire about their response to sildenafil and using the 5-item International Index of Erectile Function (IIEF-5) questionnaire. RESULTS: Thirty-three of the 43 patients were eligible for evaluation of the efficacy of sildenafil and 27 completed the IIEF-5 questionnaires. Sildenafil at 50 mg had a better effect on sexual function than 25 mg in most Japanese patients. Of the 16 patients who underwent bilateral NS procedures, 10 (62.5%) had improved ability for intercourse and 3 (18.8%) had improved erections. Of the 13 patients who underwent unilateral NS procedures, 7 (53.8%) had improved ability for intercourse and 4 (30.8%) had improved erections. None of the 4 patients who underwent non-NS procedures had a positive response. Of 24 patients with positive response to sildenafil, 3 (12.5%) did not have to take sildenafil after receiving it because they did not require it for intercourse. Mean IIEF-5 score increased from 4.3 to 11.4 (P < 0.0001). Patient age, time since surgery, PSA and pathological stage did not have statistically significant effects on outcome. The most commonly cited adverse effect was headache (21%). CONCLUSION: Sildenafil is equally effective for erectile dysfunction in Japanese patients who have undergone bilateral and unilateral NS procedures, and aids recovery of natural erectile function after radical retropubic prostatectomy. However, non-NS procedure patients had no response to sildenafil. This study suggested that sildenafil is well tolerated and should be initially used for treatment of Japanese men with erectile dysfunction after radical retropubic prostatectomy.     

Therapeutic effectiveness and patient satisfaction after 6 months of treatment with tadalafil, sildenafil, and vardenafil: results from the erectile dysfunction observational study (EDOS)

OBJECTIVE: This observational study was conducted across Europe to assess health outcomes in men with erectile dysfunction (ED) who took tadalafil, sildenafil citrate (sildenafil), or vardenafil HCl (vardenafil) for 6 mo. METHODS: Therapy effectiveness and patient satisfaction were evaluated using established and new questions on erectile function. Behavioural, psychological, and relationship outcomes were assessed using the short form of the Psychological and Interpersonal Relationship Scales (SF-PAIRS). RESULTS: In nine European countries at 904 sites, 8047 patients were enrolled and 94% (7560) selected either tadalafil (5315), sildenafil (1252), or vardenafil (993) for treatment at baseline. Of the 7560, 3998 (52.9%) took the same drug for 6 mo. Baseline characteristics across the three treatment groups were comparable: mean age approximately 56 yr, moderate or severe ED, and mean International Index of Erectile Function-Erectile Function domain score about 13. Tadalafil, sildenafil, and vardenafil were therapeutically effective and improved patient satisfaction in the 40-58% of men who completed 6 mo of a single therapy. Patients taking tadalafil consistently had numerically higher levels of therapeutic effectiveness and satisfaction compared with patients who took sildenafil or vardenafil. The three cohorts had statistically significant changes from baseline in response to SF-PAIRS and there were significant differences, in favour of tadalafil, among cohorts in the Time Concerns domain. CONCLUSION: In a large observational study that mimics a routine clinical setting, most patients selected an inhibitor of phosphodiesterase 5 to treat ED, which resulted in a high level of therapeutic effectiveness and patient satisfaction.     

Rehabilitación endotelial del tejido cavernoso con sildenafilo 100 mg en pacientes sometidos a prostatectomía radical

ObjectivesWe try to figure out whether early penile rahabilitation ameliorates erectile dysfunction secondary to radical prostatectomy.Material and methodsRetrospective study of 80 cases of patients that were operated between 2005-2008; all of them went under radical prostatectomy and were treated with sildenafil 100mg every second day (Monday, Wednesday and Friday) plus 100mg on demand after the surgery. As objective measurements, we used validated questionnaire IIEF-5 and also axil penile rigidity before and after surgery in the third and ninth month.ResultsPatients treated with sildenafil in fixed doses presented a 60% full erection recovery 9 months after radical prostatectomy. In the case where patients underwent bilateral or unilateral nerve sparing, they got a successful rate of almost 90%. Even 20% of those patients who did not have a nerve preservation got satisfactory erections.ConclusionsOur experience shows that early penile rehabilitation seems to be a good treatment for erectile dysfunction after radical prostatectomy with ipde5 in fixed doses. administration every other day plus on demand looks like also as an appropriate option.     

Efficacy, safety and patient acceptance of sildenafil citrate as treatment for erectile dysfunction

PURPOSE: We assessed the efficacy and safety of sildenafil citrate as treatment for erectile dysfunction. MATERIALS AND METHODS: A total of 433 completely evaluated men with chronic erectile dysfunction were treated with sildenafil citrate. Response was assessed prospectively by baseline and followup physician interviews, and by a patient self-administered 15-item questionnaire on the domains of patient treatment response and satisfaction, partner treatment satisfaction, comparative previous treatment satisfaction, adverse effects, and patient and partner quality of life. RESULTS: Of the 304 men (70.2%) who completed the questionnaire 278 received sildenafil, including 186 who previously had undergone treatment for erectile dysfunction, principally involving intracavernous injection therapy. A response was elicited by a median dose of 100 mg. in 188 patients (67.6%) who achieved erection suitable for sexual intercourse. Those with psychogenic erectile dysfunction responded significantly better than those with organic dysfunction (p <0.001). Erection suitable for intercourse was attained by 30.8% of patients with erectile dysfunction after radical prostatectomy and 80% with cavernous veno-occlusive dysfunction. Of previous intracavernous injection responders 29.9% were refractory to sildenafil, while 33. 3% of previous intracavernous injection nonresponders responded to sildenafil. The sildenafil response was considered inferior to the intracavernous injection response by 43.6% of the men who previously responded to intracavernous injection, of whom 51.5% continued to receive intracavernous injection as the only treatment (19.5%) or as an alternative to sildenafil (32%). Adverse effects in 53.6% of cases were assessed as mild in 56.4%, moderate in 38.3% and severe in 5.3%. Multiple adverse effects were reported by 62.4% of patients, while 17 (6.1%) discontinued sildenafil as a direct result of intolerable adverse effects. The most common adverse effects were facial flushing in 33.5% of cases, headaches in 23.4%, nasal congestion in 12.6%, dyspepsia in 10.1% and dizziness in 10.8%. Baseline patient and partner quality of life scores significantly improved after sildenafil treatment (p <0.001), while significantly improved quality of life was noticed by 51.5% and 43.1%, respectively. CONCLUSIONS: Sildenafil citrate is effective oral first line treatment for erectile dysfunction. Although more than 50% of men reported adverse effects, most were considered mild and rarely resulted in treatment cessation. There was a trend in those on intracavernous injection who responded to sildenafil to continue intracavernous injection as the only therapy or as an alternative to sildenafil. Also, we noted that some cases refractory to sildenafil responded to intracavernous injection. These findings imply that intracavernous injection remains an effective erectile dysfunction treatment option.     

伐地那非在难治性ED人群中的应用

本文回顾了高选择性口服磷酸二酯酶5(PDE5)抑制剂伐地那非在各种难治性ED人群的疗效和安全性。结果表明,伐地那非对于合并糖尿病、抑郁症、前列腺切除术后、外伤性脊髓损伤性、以及西地那非治疗无效的ED患者安全有效,为这些难治性ED人群提供了一种合理的治疗选择。     

同期内使用3种PDE5抑制剂治疗ED的经验

目的:观察与比较同期内使用3种PDE5抑制剂治疗ED患者的疗效,满意情况和不良反应。分析影响患者疗效、接受度、倾向性的因素。方法:11个月在门诊应用3种PDE5抑制剂治疗ED患者331例。使用西地那非134例,他达拉非88例,及伐地那非109例。医师详细指导药物的应用,注意事项,观察的内容等,并互留电话,列表登记、随访。结果:复诊或电话随访时间,结果为:①获得良好的疗效及满意率为西地那非72例(79.12%),他达拉非52例(78.78%),伐地那非63例(81.81%)。②PDE5抑制剂单纯或交叉应用的资料分析显示:青年患者或新婚者,偏好伐地那非;③中青年患者倾向于他达拉非;中老年及较长期应用PDE5抑制剂的患者多选用西地那非。3种PDE5抑制剂用于早泄均有一定疗效。④对不能继续用此类药治疗ED的原因进行了分析,分别为:价高,不治本,效果差,耽心不良反应。结论:①同期3种PDE5抑制剂治疗ED的疗效基本相近。亦各有一些优势和特点。②3种PDE5抑制剂的安全性均好,一般、轻度不良反应相近,中度、特殊的不良反应少,严重不良反应均无发生。③PDE5抑制剂的疗效观察,目前众多的问卷、量表实际均仍以主观的感受为主。对同一个人以相同形式、相同问题、繁简一致阐述,获得的有关疗效满意情况、感受等简易回答是有可比性、可信度和实用性的。     

Effect of sildenafil citrate on post-radical prostatectomy erectile dysfunction

PURPOSE: We assess the effect of sildenafil in a subgroup of patients after prostatectomy with erectile dysfunction and determine whether nerve preservation improves sildenafil response in this subgroup. MATERIALS AND METHODS: Between April 1998 and January 1999, 53 patients who had undergone radical retropubic prostatectomy and were prescribed oral sildenafil were surveyed using a confidential mail questionnaire. Of the patients 21 underwent bilateral and 15 unilateral neurovascular bundle sparing procedures, while in 17 a nonnerve sparing procedure was performed. All patients received 25 to 100 mg. sildenafil in a flexible dose escalation manner. Response, satisfaction and side effects were assessed using a modified, self-administered International Index of Erectile Function questionnaire. Response was defined as erection sufficient for intercourse. Preoperative and postoperative/pretreatment erectile functions were assessed for baseline comparison in each patient, and partner overall satisfaction with sildenafil was measured. Statistical data analysis was performed using analysis of variance and Newman-Keuls multiple comparison tests. RESULTS: Of the 21 patients who underwent a bilateral nerve sparing procedure 15 had a positive response. Of the 15 patients who had undergone a unilateral nerve sparing procedure 12 had a positive response, and only 1 of the 17 patients who had undergone a nonnerve sparing procedure responded to sildenafil. The most commonly reported adverse events of all causes were headaches (21%), flushing (8.3%), visual disturbance (6.3%) and nasal congestion (6.3%). CONCLUSIONS: Sildenafil is an equally effective treatment for erectile dysfunction after bilateral and unilateral nerve sparing procedures, and patient response to sildenafil is confirmed by the partners. However, patients who undergo nonnerve sparing procedures do not respond satisfactorily to sildenafil.     

Evidence for contamination of herbal erectile dysfunction products with phosphodiesterase type 5 inhibitors

PURPOSE: We determined if pharmacological dosages of phosphodiesterase type 5 inhibitors (PDE5) inhibitors were present within a group of natural products marketed for the treatment of erectile dysfunction. MATERIALS AND METHODS: Seven herbal products marketed for the treatment of erectile dysfunction were purchased via the Internet or at local health food stores. Specimens were batched, relabeled and blindly analyzed for contamination with PDE5 inhibitors. High performance liquid chromatography and mass spectrometry were used to detect evidence of contamination with sildenafil, tadalafil or vardenafil. RESULTS: Of the 7 tested products 2 contained pharmacological dosages of sildenafil and tadalafil. Contamination with vardenafil was not identified. Mean dosages of sildenafil and tadalafil were 30.2 and 19.7 mg, respectively. CONCLUSIONS: A significant proportion of natural products marketed for erectile dysfunction contains PDE5 inhibitors. Although marketed as natural products devoid of adverse effects, these agents are known to have potentially fatal drug interactions with nitrates. Better regulation of the natural health products industry is urged.