Introduction
In the past few years, there has been an increase in the number of advertisements regarding erectile dysfunction. You've probably seen former Presidential candidate Bob Dole or Baltimore Oriole Rafael Palmeiro in television commercials informing viewers of erectile dysfunction and the use of Viagra. Former professional football player and coach Mike Ditka has also been seen educating viewers about the once taboo subject of erectile dysfunction. With heightened awareness of this disorder, the attitudes of the public and healthcare professionals are changing with more individuals seeking help with the disorder.
What is it?
Erectile dysfunction (ED), sometimes called "impotence", is the inability to achieve or maintain an erection for sexual intercourse. Impotence can involve three aspects of erection development: the time to develop an erection, the strength of the erection, or the amount of stimulation needed to achieve an erection. Erectile dysfunction may be a result of a variety of factors, ranging from chronic diseases, medications, to psychological factors.
What causes it?
Before discussing the causes of erectile dysfunction, it is important to understand how an erection develops and how an erection is sustained. The penis is made of a mass of tissue composed of several structures of spongy networks that contain blood vessels and smooth muscle tissue. Normal nerve function and blood supply to these areas is essential to experience and maintain an erection. When sexual arousal takes place (whether it be a result of visual stimuli, touches, smells, or thoughts), the brain responds by communicating the arousal to the body's nervous system, which activates blood flow to the penis. As blood flow increases in the penile area, blood vessels supplying the penis dilate so the body of erectile tissue becomes engorged. When the erectile tissue engorges, an erection develops.
If something affects any of the factors responsible for an erection, erectile dysfunction may result. Psychological factors or nonphysical factors may also contribute to erectile dysfunction. Such factors may include depression, stress, anxiety, negative feelings toward a sexual partner, or even feelings of dissatisfaction with sexual function.
Although psychological and nonphysical causes are possible, there are several physical causes that may contribute to erectile dysfunction. Common diseases such as diabetes, high blood pressure, atherosclerosis (hardening of the arteries), thyroid problems, and alcoholism may also cause erectile dysfunction. Spinal cord injury, multiple sclerosis, or other diseases that may affect nerve conduction to the penile area can decrease the likelihood of achieving or maintaining an erection. Low hormone levels (for example, low levels of testosterone or prolactin) may also be a cause of erectile dysfunction, although the incidence of this cause is thought to be much less than the common diseases such as diabetes. Studies have even shown that the pressure obtained from riding a bike, which comes from sitting on a bicycle seat with a nose extension, restricts blood flow to the penis.
Certain prescription medications and illicit drugs may cause erectile dysfunction. Up to 25% of cases of erectile dysfunction result from medication side effects. Examples of prescription medications that may lead to erectile dysfunction include certain antidepressants, medications for high blood pressure, antipsychotics, medications used for anxiety disorders, anticholinergics (e.g. diphenhydramine, benztropine, and atropine), cimetidine, digoxin, and substances of abuse (e.g. alcohol, cocaine, and marijuana). Check with your doctor or pharmacist if you suspect that a medication you are taking may be the cause of erectile dysfunction.
Who has it?
Erectile dysfunction can affect all age groups. It has been estimated that 18 to 30 million American men suffer from erectile dysfunction. This number has increased significantly as awareness of the disorder has heightened. Researchers and health care professionals now have a better understanding of what causes erectile dysfunction and the effective medications used to treat the condition.
What are the risk factors?
Numerous physical and emotional risk factors may contribute to erectile dysfunction. Many of these risk factors are similar to the causes of the disorder. Risk factors may include the following:
- Physical diseases, disorders, or conditions - Chronic diseases such as diabetes, high blood pressure, atherosclerosis (hardening of the arteries), thyroid diseases and disorders affecting the nerves are risk factors for developing erectile dysfunction. Also, men greater than the age of 40 are at risk for developing erectile dysfunction.
- Surgery or trauma- surgeries to treat the bladder, rectum, or prostate can also result in erectile dysfunction; erectile dysfunction can also result from injury to the pelvic area or spinal cord.
- Prescription medications - Certain antidepressants, antipsychotics, medications used to treat anxiety disorders and high blood pressure, anticholinergics (e.g. diphenhydramine, benztropine, and atropine), cimetidine, and digoxin have been shown to contribute to erectile dysfunction. If you are experiencing erectile dysfunction, talk to your doctor or pharmacist to see if any of your medications may be the cause.
- Nonphysical disorders - Stress, depression, anxiety, or even negative feelings toward a sexual partner can cause erectile dysfunction.
- Substance abuse - Alcohol, anabolic steroids, heroin, cocaine, and marijuana have also been shown to lead to erectile dysfunction.
The inability to achieve or maintain an erection is the main symptom of erectile dysfunction. The inability to develop an erection may or may not occur every time an individual becomes aroused. If you consistently experience erectile dysfunction for longer than 2 months, contact your doctor so the cause of the dysfunction may be determined.
How is it treated?
The first step in the treatment of erectile dysfunction is a physical examination. This is done to rule out disorders such as diabetes, high blood pressure, high cholesterol, kidney disease, alcoholism, or multiple sclerosis, which can cause erectile dysfunction. It is estimated that physical diseases or conditions are the cause of erectile dysfunction approximately 70% of the time.
An important part of the evaluation should be a detailed patient history, which can give the doctor valuable clues about the patient's condition and the degree of severity of the condition. Usually, the doctor will ask about sexual activity and carefully discuss all of the patient's symptoms, which may help determine if the patient is having problems with erection, ejaculation, orgasm, or sexual desire. The treatment of erectile dysfunction is tailored to the individual, with the severity and cause of the erectile dysfunction taken into account.
Prescription medications like Viagra (sildenafil), Levitra (vardenafil), and Cialis (tadalafil) are frequently prescribed, but vacuum devices, penile implants, and vascular surgery are also options for the treatment of ED. It may also be helpful for some patients to receive psychological therapy as well.
Drug Therapy
First-line medications for the treatment of ED are phosphodiesterase inhibitors which include Viagra, Cialis, and Levitra. These medications work by preventing the breakdown of nitric oxide, causing relaxation of the muscles in the penis. This allows more blood to flow into the penis improving an erection. In order for these medications to work, sexual stimulation is needed. One advantage to Cialis is that it has been shown to improve erectile function for up to 36 hours following a dose while Viagra lasts for 4 hours and Levitra lasts for 5 hours. Cialis also has a faster onset of action of 15 minutes compared to Viagra and Levitra which have an onset of action of 30 minutes. This allows for more flexibility in planning sexual intercourse.
Although not first-line, several other drug classes are available. One of these is the prostaglandin E analogs which includes alprostadil. Alprostadil is a hormone that causes relaxation of the muscle tissue in the penis allowing for an erection. Alprostadil is available in two forms. With the injectable form (Caverject, Edex), a fine needle is used to inject the hormone into the penis. With the intraurethral form (Muse), a tiny suppository is inserted into the tip of the penis. Yohimbine, an alkaloid, is also sometimes used to treat ED. It is not thought to be effective for most men, but may be helpful to men whose ED is due to nonphysical causes such as stress or anxiety. Testosterone may also be helpful in treating ED in men who have a testosterone deficiency.
Vacuum Devices
Vacuum devices are non-drug options for treating erectile dysfunction. The device creates a vacuum around the penis, which draws blood into the penis and allows it to engorge, hence causing an erection. The devices are made up of three parts: a plastic cylinder that is placed over the penis; a pump which draws air out of the cylinder; and an elastic band which is placed around the base of the penis to maintain erection after the cylinder is removed and during intercourse to keep the penis engorged with blood.
Penile Prosthesis & Implants
Penile prosthesis/implants are another non-drug option for treating erectile dysfunction. A penile implant or inflatable prosthesis can be surgically embedded into the penis. With an inflatable prosthesis, fluid is pumped from a holding chamber in the abdomen into hollow cylinders placed within the corpora cavernosa (the 2 chambers inside the penis). The inflation and deflation of the hollow cylinders can be done by the patient as desired. An easy way to think about it is that penile implants function similarly to putting water into a latex balloon. As water is put into a balloon, the balloon expands (much like pumping fluid into the hollow cylinders of the penile implant makes the penis become erect). As water is let out of the balloon, the balloon deflates (much like deflating the fluid from the penile implants then makes the penis become flaccid again). Penile implants have a high satisfaction rate with patients. However, complications of the penile implant include infections, which can lead to the removal of the prosthesis. The cost of treating an infected prosthesis can actually exceed the cost of the original implant.
Surgery
Vascular surgery is another non-drug option for this disorder. Surgery can be performed to restore blood flow to the penile area if the vasculature (blood vessels) to the area is compromised. These types of surgeries have fallen out of favor in recent years due to the possible risk of infection associated with such invasive procedures. As a result, prescription medications have become the treatment of choice for erectile dysfunction.
Psychological Therapy
Psychological therapy and behavior modifications are other options to treat erectile dysfunction. This method targets any anxiety that may be associated with sexual intercourse. If your doctor feels this is an issue for you, a visit to a psychologist or psychiatrist may be warranted.
Drug classes used to treat Erectile Dysfunction
- Alkaloids for erectile dysfunction
- Phosphodiesterase Enzyme Inhibitors
- Prostoglandin E Analogs
- Testosterone for erectile dysfunction
A new regular dosing schedule for sildenafil (Viagra) and the other phosphodiesterase enzyme inhibitors like tadalafil (Cialis) and vardenafil (Levitra) may restore erectile function more effectively than an "as needed" dosing schedule. According to a recent study, Viagra taken every night may provide more nocturnal erections which may benefit patients with erectile dysfunction. The significance of the benefit, however, has yet to be determined by larger, more conclusive studies. The safety of an "every day" treatment pattern has also not been determined and is therefore discouraged at this time.
Because of the success and wide spread use with sildenafil (Viagra) for erectile dysfunction, researchers are focusing on other noninvasive treatment options to treat erectile dysfunction. Currently, a form of phentolamine to be taken by mouth is being studied to determine its effectiveness in treating erectile dysfunction. Another study is looking at the use of radiation treatments to improve erections.
There was a study conducted in patients taking sildenafil (Viagra) to see if this medication is still effective 8 hours after taking the dose. The study measured if patients with mild to moderate erectile dysfunction will have difficulty obtaining an erection 8 hours after the first dose of Viagra. This study is most likely being carried out to make Viagra more competitive with Cialis, which works up to 36 hours after the dose is taken. The study has been completed, however the results have not yet been reported.
Researchers think they may have found a way to help men avoid impotence caused by nerve damage. While they haven't tried their approach on humans yet, the researchers say tests on rats suggest that a type of gene therapy may bring back the ability to have an erection. Individuals with diabetes and/or whom have had their prostate removed are at risk for nerve damage.
