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.
Myocardial ischaemia is caused by the reduction of coronary blood flow as a result of fixed or dynamic epicardial coronary artery stenosis, abnormal constriction or deficient relaxation of coronary microcirculation, or because of reduced oxygen-carrying capacity of the blood.56 Atherosclerosis is the major cause of myocardial ischaemia. Plaque that develops in atherosclerosis can rupture causing platelet aggregation and subsequent thrombus formation, which leads to MI. The other mechanisms of myocardial ischaemia are encountered far less than atherosclerosis. Endothelial dysfunction has an important role in the progression of atherosclerosis. Endothelial dysfunction enhances the intimal proliferation and malregulation that results in plaque destabilisation in the arteries.6 This process, coupled with paradoxical vasoconstriction, can result in major cardiovascular events such as MI.32

Yet another common erectile dysfunction treatment that can be used in combination with oral drugs is a vacuum pump. This device consists of a plastic cylinder, a pump, a set of constriction bands, and a water-soluble lubricant. The lubricant is applied to the base of the penis to help form an airtight seal. The cylinder is placed over the flaccid penis and held tight against the pelvis. The pump is used to create a vacuum within the cylinder, drawing blood into the penis. Once the penis is engorged with blood, a constriction band is rolled off the cylinder to near the base of the penis. The constriction band is helpful for men with venous leakage, in which blood flows out of the penis as fast as it flows in. However, it should be left on for no more than 30 minutes at a time.
The initial event for normal erectile function is sexual stimulation. Subsequent to processing in the central nervous system neural impulses are conveyed along the spinal cord, exiting through the pelvic parasympathetic preganglionic nerves. These pelvic nerves form the pelvic plexus and send their message through first messenger, acetyl choline, to the cavernosal nerves. The cavernosal nerves enter erectile bodies (corpora cavernosa) (Figure 1). Here, their nerve endings release a second messenger, nitric oxide. Nitric oxide activates the enzyme guanylyl cyclase, which lyses guanosine triphosphate (GTP) to produce a third messenger, the intracellular cyclic guanosine monophosphate (cGMP). Ultimately, the result is a decrease of intracellular calcium and an opening of potassium channels with the resultant relaxation of vascular smooth muscle in the arteries, aterioles, and sinusoids of the corpora cavernosa. The sinusoids open and rapidly fill with blood. Finally, the distended sinusoids compress their drainage pathways (venules) against the fibroelastic covering of the cavernosal bodies (tunica albuginea) and trap the blood in cavernosal bodies. The combination of an increased inflow of blood into the penis and coincident markedly diminished outflow results in rapidly increasing intracavernosal pressure that ultimately approximates systolic pressure. At this pressure the penis has sufficient axial rigidity to permit vaginal penetration.

If you’re taking medication to treat blood pressure, depression, pain, allergies, inflammation, seizures, or heart conditions, you’re one of the tens of millions of people at risk for medically induced erectile dysfunction. It’s just the nature of drug side effects. Yet erectile dysfunction is one of the least talked about side effects of prescription medication.
However, sildenafil should be used carefully with nitrates because their combination can result in severe hypotension and death.68 Both short- and long-acting nitrates are commonly prescribed to treat angina, but they have no prognostic benefit. In addition, there are numerous alternatives to treat angina, such as ranolazine and ivabradine, which do not interact with PDE5 inhibitors. As a result, patients with ED wishing to take PDE5 inhibitors can safely discontinue their nitrates and replace this treatment with the other anti-anginal agents.68
A number of drugs are known to cause ED in patients with DM (Table 1). For example, many EDDM patients are on antihypertensive medications. Replacement of thiazides or beta-blockers with angiotensin-converting enzyme inhibitors or angiotensin receptor blockers may be sufficient to regain erectile ability.5 Furthermore, discontinuation of selective serotonin reuptake inhibitors, if these drugs are not essential for patient well-being, may be therapeutic. Careful monitoring following drug discontinuation will help to determine if ED is due to the medication or other underlying disorders. The benefits of continued drug therapy with these drugs should always be weighed against the likelihood of causing ED and impacting on the patient's QOL.
Now that we better appreciate the complex sequence of events necessary for erections to occur, it’s no surprise that testosterone alone yields less than perfect results. Erectile dysfunction represents more than just low testosterone, which is just one facet of the spectrum of dysfunctional phenomena that cause sexual dysfunction. Nonetheless, when testosterone is combined with popular drugs like Viagra®, success is enhanced to an even greater degree—orgasmic function improves, along with erectile capacity and libido.20 Testosterone also activates penile nitric oxide; ultrasound studies have demonstrated a 27% increase in arterial blood flow into the penis with testosterone supplementation.23
Towards this direction, several sufficiently powered studies have demonstrated a higher incidence of erectile dysfunction in patients with coronary artery disease, either asymptomatic or overt. At the same time, patients with erectile dysfunction are more prone to have established coronary artery stenosis of more than 50% and consequently evident CV disease[75]. This is in conformity with the “artery size hypothesis” according to which smaller arteries (e.g., penile arteries) are the first to undergo a vascular lesion prior to the larger ones (e.g., coronary arteries). Moreover, in such patients erectile dysfunction is connected to the number of occluded vessels and more interestingly occurs over three years before coronary artery disease becomes apparent[76-80].
A significant proportion (ranging from ∼60 to 90%) of heart failure patients report ED and marked decrease in sexual interest, with ultimately one-quarter reporting cessation of sexual activity altogether.48 Erectile dysfunction contributes further to the poor quality of life and aggravates depression. Of interest, many heart failure patients place a greater importance on improving the quality of life (including sexual activity) than on improving survival. Sexual function correlates with the symptomatic status (i.e. NYHA functional class and 6-minute walk test).48 In the Evaluation of Role of Sexual Dysfunction in the Saarland (EROSS) Program, left ventricular dysfunction was a risk factor for ED independent of heart failure symptoms. While heart failure and ED share common pre-disposing risk factors, heart failure by itself can cause ED or affect engagement to sexual activity. Neurohumoral activation, medication (thiazides), limited exercise capacity, and depression are responsible.49
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.
PubMed | Google ScholarSee all References Diabetes was found to play a major role in vasculogenic impotence in a study of 265 patients with ED who underwent color duplex ultrasonography of the cavernosal arteries after intracavernosal injection of prostaglandin E1.13x13Chung, WS, Shim, BS, and Park, YY. Hemodynamic insult by vascular risk factors and pharmacologic erection in men with erectile dysfunction: Doppler sonography study. World J Urol. 2000; 18: 427–430

The development of PDE5-inhibitors is a clear example of how Western medicine approached the problem of ED differently from Eastern medicine. The erectogenic effect of sildenafil (Viagra®) was discovered by accident when patients undergoing heart clinical trials reported better erections as a side effect after taking sildenafil. This observation led to further elucidation of the NO/cGMP signalling pathway and development of PDE5-inhibitors as a first-line therapy in ED (5).
It’s crucial that any underlying medical condition, such as angina or diabetes, is detected. So if you’re experiencing problems with ED, book an appointment with your doctor. He or she will assess and examine you to try to establish the cause of the problem, and may refer you for tests. Don’t take any medicine for ED without first discussing it with your doctor.
Yet another common erectile dysfunction treatment that can be used in combination with oral drugs is a vacuum pump. This device consists of a plastic cylinder, a pump, a set of constriction bands, and a water-soluble lubricant. The lubricant is applied to the base of the penis to help form an airtight seal. The cylinder is placed over the flaccid penis and held tight against the pelvis. The pump is used to create a vacuum within the cylinder, drawing blood into the penis. Once the penis is engorged with blood, a constriction band is rolled off the cylinder to near the base of the penis. The constriction band is helpful for men with venous leakage, in which blood flows out of the penis as fast as it flows in. However, it should be left on for no more than 30 minutes at a time.
×