To date, there are no studies directly comparing the effectiveness of these three agents among diabetic men with ED, so it is impossible to state that one agent is superior to another in terms of effectiveness in diabetic patients. However, there are an number of studies that compare the individual agents to placebo in diabetic men with ED. For example, Boulton et al.41 completed a 12-week double-blind, placebo-controlled randomized clinical trial of the effectiveness of sildenafil in 219 men with ED and type 2 diabetes. They found that sildenafil resulted in a significant improvement in the ability to both achieve and maintain an erection adequate for sexual intercourse in men with type 2 diabetes. In a similar study, Rendell et al.42 randomized 268 diabetic men with ED to receive either sildenafil in a dose-escalation manner or placebo. At the conclusion of the 12-week study, 56% of the patients in the sildenafil arm reported improved erections, compared to 10% in the placebo arm (P < 0.001). Additionally, 61% of patients in the diabetic arm reported at least one successful attempt at sexual intercourse in the final month of the study, compared to 22% in the control arm (P < 0.001). Similar randomized studies have documented the effectiveness of both tadalafil43 and vardenafil44 in the treatment of diabetes-related ED.
Your doctor may also choose to lower your dose of certain medications. Or your provider may switch the type of drug you’re taking if it’s interfering with your sex life. Some medicines used for managing blood pressure, insomnia, anxiety, depression, seizures and prostate problems increase the risk for erectile dysfunction. Beta-blockers (for high blood pressure), SSRIs (often used to treat depression) and the class of drugs called benzodiazepines (like Ativan, Xanax, Librium and Valium) are commonly tied to ED. You may want to speak to your doctor about this.
First of all, libido (sexual desire) triggers a sympathetic (adrenaline-dependent) nervous system reaction mediated through the thoracic spinal cord. Also important is tactile stimulation, the pleasurable effect of touch, which is mediated through the acetylcholine-dependent parasympathetic nervous system. Both the sympathetic and parasympathetic forces regulate the release of nitric oxide—the universal artery-relaxing agent—from the cells lining the penile arteries and all its smaller branches. Nitric oxide causes the arteries to enlarge, increasing blood flow into the penile tissues. This is followed by compression of blood-draining penile veins, which causes blood to engorge the penis and create an erection.4
This category of treatments includes external vacuum therapies: devices that go around the penis and produce erections by increasing the flow of blood in, while constricting the flow out. Such devices imitate a natural erection, and do not interfere with orgasm. External vacuum therapy mechanisms are approximately 95 percent successful in causing and sustaining an erection. All are portable, and costs range between $200-$500, covered under most insurance plans and Medicare Part B.
The vascular endothelium has an important role in angiogenesis and vascular repair by producing regulatory substances, including NO, prostaglandin, endothelins, prostacyclin and angiotensin II. These regulatory factors regulate the blood flow to the penis by controlling smooth muscle contractility and subsequent vasoconstriction and vasodilatation. Generally, in erectile tissue, increased blood flow through the cavernosal artery increases shear stress and produces NO, which further relaxes the vascular smooth muscles and increases blood flow in the corpora cavernosa.54 These events cause penile erection. However, in ED, endothelial NO synthesis is reduced and there is increased endothelial cell death (Figure 2).55
Second-generation cardioselective beta-blockers (atenolol, metoprolol, bisoprolol, etc.) can also lead to ED. Atenolol was shown to cause significant reduction of sexual activity compared with placebo in a double-blind, parallel-arm study.22 The same study also showed a significant reduction in testosterone levels with atenolol versus valsartan. An open, prospective study of hypertensive men treated with atenolol, metoprolol and bisoprolol for at least 6 months showed high prevalence of ED – approaching 66 % – in these patients.23

Physical and sexual activity can trigger acute cardiac events. In a recent meta-analysis, a significant association between acute cardiac events and episodic physical (relative risk 3.45 for myocardial infarction and 4.98 for sudden cardiac death) and sexual activity (relative risk 2.7 for myocardial infarction) was demonstrated.32 This association was attenuated among individuals with high levels of habitual physical activity (for every additional time per week the relative risk for myocardial infarction decreased by ∼45%, and the relative risk for sudden cardiac death decreased by 30%). The physical demands of sexual activity have been identified as follows. Studies conducted primarily in young married men showed that sexual activity with a person's usual partner is comparable with mild-to-moderate physical activity in the range of 3–4 metabolic equivalents of the task (METS).30,33 The heart rate rarely exceeds 130 b.p.m. and systolic blood pressure rarely exceeds 170 mmHg in normotensive individuals. Accordingly, demands during sexual activity correspond to walking 1.5 km (or 1 mile) on the flat in 20 min or briskly climbing two flights of stairs in 10 s. Generalization, however, may not characterize all individuals (especially those who are older, are less physically fit, or have CVD) or sexual activity circumstances (e.g. extramarital, unfamiliar setting, excessive food and alcohol consumption). Therefore, completing 4 min of the standard Bruce treadmill protocol (5–6 METS) without symptoms, ST segment changes, arrhythmias, or a fall in systolic BP identifies the safety of sexual activity.30,33
Organic nitrates are drugs that widen arteries by increasing their supply of nitric oxide; that's how they open the partially blocked coronary arteries in patients with angina. But because nitrates and ED pills both act on nitric oxide, the drugs don't mix; healthy volunteers given Viagra followed an hour later by nitroglycerin see their blood pressures drop by 25–51 mm Hg, a potentially dangerous amount. All experts agree that men who are taking nitrates cannot use ED pills; this includes all preparations of nitroglycerin (short-acting, under-the-tongue tablets or sprays), long-acting nitrates (isosorbide dinitrate or Isordil, Sorbitrate, and others, and isosorbide mononitrate, Imdur, ISMO, and others), nitroglycerin patches and pastes, and amyl nitrite or amyl nitrate (so-called poppers, which some men use for sexual stimulation).
Chlamydia and erectile dysfunction: What's the link? Some people who have chlamydia also experience erectile dysfunction (ED), which involves problems getting or maintaining an erection. Chlamydia can infect the prostate gland, leading to prostatitis, pain, and ED. In this article, learn more about the link between this common infection and ED, and treatments for both. Read now
In some cases, however, these drugs may be unsuitable for patients with heart disease. If you are considering one of these drugs and you have heart disease, as many diabetics do, be sure to tell your doctor. In rare cases, the pills may create “priapism,” a prolonged and painful erection lasting six hours or more (although reversible with prompt medical attention).
Sildenafil should be taken 1–2 h before intercourse. It is important to tell patients that the drug’s effectiveness requires sexual stimulation. One patient in our clinic recently complained that he had no effect from taking sildenafil. It was later discovered that he took the pill and then sat on his couch and read a book about how to grow tomatoes!

If you have several atherosclerotic risk factors or symptoms of heart disease, your doctor might do additional tests to look for atherosclerosis in the coronary arteries. A stress test involves monitoring the heart with an electrocardiogram or images before and after exercise. An angiogram, or cardiac catheterization, involves entering a blood vessel in the leg or wrist to pass instruments into the heart to directly visualize the coronary arteries. During this procedure, atherosclerosis can be treated by inflating a balloon or placing a metal stent in the coronary blood vessel to keep it open. If you and your doctor begin a treatment plan to prevent atherosclerosis at the first sign of ED, then you may significantly delay or prevent the need for these more invasive procedures.
If you have symptoms of ED, it’s important to check with your doctor before trying any treatments on your own. This is because ED can be a sign of other health problems. For instance, heart disease or high cholesterol could cause ED symptoms. With a diagnosis, your doctor could recommend a number of steps that would likely improve both your heart health and your ED. These steps include lowering your cholesterol, reducing your weight, or taking medications to unclog your blood vessels.
Having ED means that all, most, or some of the time, the penis fails to become or stay hard enough for sexual intercourse. If, on rare occasions, you cannot get an erection, you do not have ED. You also do not have ED if you have a decrease in sexual desire, have premature ejaculation, or if you fail to ejaculate or reach orgasm. ED means that you can’t get or keep an erection.

It is recommended that testosterone be measured in patients with ED because low levels are a reliable measure of hypogonadism. Hypogonadism is not only a treatable cause of ED, but can also lead to reduced or lack of response to PDE5 inhibitors.73 Testosterone deficiency is also associated with increased cardiovascular and all-cause mortality.74 Levels >350 ng/dl do not usually require replacement, but in patients with testosterone <230 ng/dl, replacement can usually be beneficial.57 In patients with congestive heart failure, testosterone replacement can lead to fluid retention, so caution is advised. In these patients, the aim should be to keep testosterone levels in the middle range, i.e. 350–600 ng/dl.57
Crossref | PubMed | Scopus (53) | Google ScholarSee all References This study found that, although hypertensive patients had more coronary artery disease, no direct evidence supported an association between hypertension and arteriogenic impotence, as measured by the PBI, peak systolic velocity, and resistive index, in patients with mild to moderate hypertension.
Crossref | Google ScholarSee all References A 1985 study found that ED accounted for 400,000 outpatient visits and 30,000 hospital admissions per year in the United States, with a direct total cost of $146 million.4x4Feldman, HA, Goldstein, I, Hatzichristou, DG, Krane, RJ, and McKinlay, JB. Impotence and its medical and psychosocial correlates: results of the Massachusetts Male Aging Study. J Urol. 1994; 151: 54–61
Ohlsson C,  Barrett-Connor E,  Bhasin S,  Orwoll E,  Labrie F,  Karlsson MK,  Ljunggren O,  Vandenput L,  Mellström D,  Tivesten A. High serum testosterone is associated with reduced risk of cardiovascular events in elderly men. The MrOS (Osteoporotic Fractures in Men) study in Sweden, J Am Coll Cardiol , 2011, vol. 58 (pg. 1674-1681)https://doi.org/10.1016/j.jacc.2011.07.019
But closer questioning often revealed a very different story—men would admit that struggles to achieve an erection usually preceded a heart attack or other cardiac event by one, two, or three years. Back then, the pattern of erectile dysfunction and cardiac disease was so widespread, that most in the medical profession attributed it to simple “aging,” as common as wrinkles and constipation.
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.
Several drugs can produce erectile difficulties, but blood pressure drugs are near the top. ED is an occasional side effect of BP drugs like thiazide diuretics, loop diuretics, and beta-blockers, all of which can decrease blood flow to the penis and make it difficult to get an erection. However, other BP drugs, such as alpha-blockers, ACE inhibitors, and angioten-sin-receptor blockers, rarely cause ED.
There are so many potential reasons a man might develop erectile dysfunction (ED), it's nearly impossible to generalize the best ways to treat it. What works for one man may not work for another simply because they are having problems for different reasons. That said, it may encouraging to hear that there are a variety of options that may be considered, from psychological counseling to lifestyle changes, medications to treatments and devices.

Abstract | Full Text | Full Text PDF | PubMed | Scopus (37) | Google ScholarSee all References One MET is equal to a resting state, or 3.5 mL/kg per minute. The relative MET values of sexual activity compared with other forms of activity are shown in Table 3. In general, sexual activity is similar to mild or moderate activity for most patients either with or without coronary artery disease.51x51DeBusk, R, Drory, Y, Goldstein, I et al. Management of sexual dysfunction in patients with cardiovascular disease: recommendations of the Princeton Consensus Panel. Am J Cardiol. 2000; 86: 62F–68F


Some doctors prefer to start a man on the lowest dose of an oral medicine and increase the dose until an effective one is found. Others prefer to start with the highest dose and go to a lower dose only if a man complains of side effects. In either case, it’s important for a man to communicate with his doctor to let him know how the dose he’s using is working.
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