The common PDE5 inhibitor drugs approved in the United States are sildenafil (Viagra), vardenafil (Levitra and Staxyn, the generic form), tadalafil (Cialis), or avanafil (Stendra). All of the currently approved PDE5 inhibitors work in the same way. They differ in the number of available doses, how quickly they work and last in your system, the dosing, and to some extent in the side effects. However, they generally share the same indications and contraindications. Currently, tadalafil is the only medication that patients can take on a daily basis and is approved for the treatment of both ED and BPH (benign enlargement of the prostate).
The male erectile response is a vascular event initiated by neuronal action and maintained by a complex interplay between vascular and neurological events. In its most common form, it is initiated by a central nervous system event that integrates psychogenic stimuli (perception, desire, etc.) and controls the sympathetic and parasympathetic innervation of the penis. Sensory stimuli from the penis are important in continuing this process and in initiating a reflex arc that may cause erection under proper circumstances and may help to maintain erection during sexual activity.
Having erection trouble from time to time isn't necessarily a cause for concern. If erectile dysfunction is an ongoing issue, however, it can cause stress, affect your self-confidence and contribute to relationship problems. Problems getting or keeping an erection can also be a sign of an underlying health condition that needs treatment and a risk factor for heart disease.

Another approach is vacuum therapy. The man inserts his penis into a clear plastic cylinder and uses a pump to force air out of the cylinder. This forms a partial vacuum around the penis, which helps to draw blood into the corpora cavernosa. The man then places a special ring over the base of the penis to trap the blood inside it. The only side effect with this type of treatment is occasional bruising if the vacuum is left on too long.
The term "impotence," as applied to the title of this conference, has traditionally been used to signify the inability of the male to attain and maintain erection of the penis sufficient to permit satisfactory sexual intercourse. However, this use has often led to confusing and uninterpretable results in both clinical and basic science investigations. This, together with its pejorative implications, suggests that the more precise term "erectile dysfunction" be used instead to signify an inability of the male to achieve an erect penis as part of the overall multifaceted process of male sexual function.
Although women tend to become more around by psychological stimuli, such as fantasies or romance novels, men tend to be more visual creatures, meaning they need to be able to actually see the object of arousal. Obviously, no two people are alike, so this is not a blanket statement, but scientific study after study over the years has shown this to be the norm.
The most common inflatable prosthesis is the three-piece penile prosthesis. It is composed of paired cylinders, which doctors surgically insert inside the penis. Patients can expand the cylinders using pressurized fluid (see figure 3). Tubes connect the cylinders to a fluid reservoir and pump, which doctors also surgically implant. The reservoir is usually in the pelvis. A doctor places the pump in the scrotum. By pressing on the pump, sterile fluid transfers from the reservoir into the cylinders in the penis. An erection is produced primarily by expansion of the width of the penis, however, one model can increase in length a small amount also. Lock-out valves in the tubing prevent the fluid from leaving the cylinder until a release valve is pressed. By pressing the relief valve and gently squeezing the penis, the fluid within the cylinders transfers back into the reservoir.

Impotence, or erectile dysfunction, is the inability of a male to attain and keep an erection sufficiently firm to engage in or complete sexual intercourse. Although it is more common in older men, impotence can occur at any age. Impotence is not a normal consequence of aging. About 70% of erectile dysfunction is due to diseases such as diabetes and atherosclerosis, another 10% to 20% is due to psychological factors, and the remaining percentage is related to medications, lifestyle factors, and injury (Source: NIDDK).


The first step in treating the patient with ED is to take a thorough sexual, medical, and psychosocial history. Questionnaires are available to assist clinicians in obtaining important patient data. (See Presentation.) Successful treatment of sexual dysfunction has been demonstrated to improve sexual intimacy and satisfaction, improve sexual aspects of quality of life, improve overall quality of life, and relieve symptoms of depression. (See Treatment.)
The drugs are worth trying, but don’t expect miracles. Everyone has heard of Viagra, but Cialis is actually more popular because it’s effective longer—24 to 36 hours instead of three to five. Erection drugs improve erections in around two-thirds of men. They don’t work for about one-third. When they work, they do not produce porn-star erections. Over time, many men need larger doses. But as dosage increases, side effects become more likely, notably, headache and nasal congestion. Finally, the drugs have no effect on arousal, so men may raise erections but don't feel particularly interested in sex. Many men feel disappointed with the drugs. Fewer than half refill their prescriptions.
You’ve heard of—and probably experienced—the numbing effect alcohol has on your mind, body, and (unfortunately) penis. If you fail to rise to the occasion on a regular basis and you're drinking has gone from occassional weekend binge to a Monday through Friday ordeal, consider cutting back—way back. Heavy drinking proportionately increases your risk of ED, according to research from the Indian Journal of Psychiatry.
This may be the oldest excuse in the book as a reason not to have safe sex, but research has confirmed that condoms may interfere with some men’s ability to have and hold an erection. For example, a 2006 study found that, over a three-month period, about 37 percent of men lost at least one erection when putting on a condom, or during sex with a condom, SexualHealth.com reported.
A lot of guys don’t want to admit it, but not being able to get or keep an erection happens more often than you’d think. Guys usually have trouble getting or keeping an erection when they’re nervous, scared or worried about something. They might be worried about how they’ll “perform,” or they could be feeling guilty about having sex. They might be afraid of getting a sexually transmitted disease (STD), or, if they are with a girl, getting their partner pregnant. Drugs (including some anti-depressants) and alcohol can also prevent you from getting and/or maintaining an erection.
A lot of guys don’t want to admit it, but not being able to get or keep an erection happens more often than you’d think. Guys usually have trouble getting or keeping an erection when they’re nervous, scared or worried about something. They might be worried about how they’ll “perform,” or they could be feeling guilty about having sex. They might be afraid of getting a sexually transmitted disease (STD), or, if they are with a girl, getting their partner pregnant. Drugs (including some anti-depressants) and alcohol can also prevent you from getting and/or maintaining an erection.
Sildenafil (Viagra) was the first oral phosphodiesterase type 5 (PDE5) inhibitor approved by the FDA in the United States for the treatment of erectile dysfunction (it is not approved for women). Sildenafil inhibits PDE5, which is an enzyme that destroys cGMP. By inhibiting the destruction of cGMP by PDE5, sildenafil allows cGMP to accumulate. The cGMP in turn prolongs relaxation of the smooth muscle of the corpora cavernosa. Relaxation of the corpora cavernosa smooth muscle allows blood to flow into the penis resulting in increased engorgement of the penis. In short, sildenafil increases blood flow into the penis and decreases blood flow out of the penis.
Whatever happens, remember there are still ways you can have fun and be intimate even if your partner can’t get an erection.  Exchanging sexy texts, reading erotic literature, and indulging in sensual massage can all help to relax, inspire and increase intimacy.  Of course, every couple is different and it may take a while to find out what works for you.

If PDE5 drugs don't work or cannot be used because of potential side effects, your doctor can recommend other therapies. The drug alprostadil (Caverject, Edex, Muse) allows blood to flow more freely in the penis, leading to an erection. The drug can be injected with a tiny needle into your penis. Or, a small pellet (suppository) can be inserted into the opening of the penis. Suppositories and injections are effective in the majority of men.


Men are very susceptible to visual stimulation, particularly as children and teenagers. Seeing anything appealing (say, a person or image) activates pathways in the brain that tell nerves in your lower spinal cord to trigger a release of nitric oxide, which relaxes blood vessel walls and floods your penis with blood, making it hard. Nitric oxide is the key chemical here, as you need a mix released from your nerves AND from your blood vessels to get an erection. If the blood vessels, nerves, or both are damaged, it's difficult to get a hard erection. That's why your doctor may well be interested if you're struggling with erections, as it could be a sign of early heart disease or diabetes.

This inflatable penile prosthesis has 3 major components. The 2 cylinders are placed within the corpora cavernosa, a reservoir is placed beneath the rectus muscle, and the pump is placed in the scrotum. When the pump is squeezed, fluid from the reservoir is transferred into the 2 cylinders, producing a firm erection. The deflation mechanism is also located on the pump and differs by manufacturer.


The link between chronic disease and ED is most striking for diabetes. Men who have diabetes are two to three times more likely to have erectile dysfunction than men who do not have diabetes. Among men with erectile dysfunction, those with diabetes may experience the problem as much as 10 to 15 years earlier than men without diabetes. Yet evidence shows that good blood sugar control can minimize this risk. Other conditions that may cause ED include cardiovascular disease, atherosclerosis (hardening of the arteries), kidney disease, and multiple sclerosis. These illnesses can impair blood flow or nerve impulses throughout the body.
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