Treatment depends on the cause. Testosterone supplements may be used for cases due to hormonal deficiency. However, the cause is more usually lack of adequate penile blood supply as a result of damage to inner walls of blood vessels. This damage is more frequent in older men, and often associated with disease, in particular diabetes.
Treatments (with the exception of testosterone supplementation, where effective) work on a temporary basis: they enable an erection to be attained and maintained long enough for intercourse, but do not permanently improve the underlying condition.
ED can in many cases be treated by drugs taken orally, injected, or as penile suppositories. These drugs increase the efficacy of nitrous oxide, which dilates the blood vessels of corpora cavernosa. When oral drugs or suppositories fail, injections into the erectile tissue of the penile shaft are extremely effective but occasionally cause priapism.
Exercise, particularly aerobic exercise is an effective cheap treatment for erectile dysfunction.
When pharmacological methods fail, a purpose-designed external vacuum pump can be used to attain erection, with a separate compression ring fitted to the penis to maintain it. These pumps should be distinguished from other penis pumps (supplied without compression rings) which, rather than being used for temporary treatment of impotence, are claimed to increase penis length if used frequently, or vibrate as an aid to masturbation. More drastically, inflatable or rigid penile implants may be fitted surgically. Implants are irreversible and costly.
All these mechanical methods are based on simple principles of hydraulics and mechanics and are quite reliable, but have their disadvantages. In a few cases there is a vascular problem which can be treated surgically.
- Oral treatment
The cyclic nucleotide phosphodiesterases constitute a group of enzymes that catalyse the hydrolysis of the cyclic nucleotides cyclic AMP and cyclic GMP. They exist in different molecular forms and are unevenly distributed throughout the body.
One of the forms of phophodiesterase is termed PDE5. The prescription PDE5 inhibitors sildenafil (Viagra), vardenafil (Levitra) and tadalafil (Cialis) are prescription drugs which are taken orally. They work by blocking the action of PDE5, which causes cGMP to degrade. CGMP specific phosphodiesterase type 5 causes the smooth muscle of the arteries in the penis to relax, allowing the corpus cavernosum to fill with blood.
These medications work when there is sexual stimulation. Depending on the treatment, it will need to be taken 20 minutes to 1 hour before sex and the period of time over which it works can vary between 3 hours and up to 36 hours.
- Alprostadil
Alprostadil can be injected into the penis or inserted using a special applicator - usually just before sexual intercourse.
Alprostadil has also become available in some countries as a topical cream (under the brand name Befar), and preliminary studies have shown a clinical efficacy of up to 83%. It has an onset of action of 10–15 minutes and its effects can last over 4 hours.
- Vacuum Therapy
These work by placing the penis in a vacuum cylinder device. The device helps draw blood into the penis by applying negative pressure. A tension ring is applied at the base of the penis to help maintain the erection.
- Counselling
Counselling is often a consideration, both where a psychological cause is suspected or must be ruled out, or to assist in management of any distress.
Controversial and unapproved treatments
ED treatment drugs have a high placebo response: if a good result is expected, any highly praised, and often expensive, treatment can be effective. Reputable drugs can also benefit from the same effect.
- Zoraxel
Currently in phase II development, Zoraxel is based on clavulanic acid and allegedly alters brain dopamine and serotonine levels, thus improving erectile function.
- Naltrexone
Drug used for treating drug addicts can have some success in patients with inhibited sexual desire.
- Bremelanotide
The experimental drug bremelanotide (formerly PT-141) does not act on the vascular system like the former compounds but allegedly increases sexual desire and drive in males as well as females. It is applied as a nasal spray. Bremelanotide allegedly works by activating melanocortin receptors in the brain. It is currently in Phase IIb trials.
- Like bremelanotide the experimental drug Melanotan II does not act on the vascular system either but increases libido. Melanotan II works by activating melanocortin receptors in the brain.
- hMaxi-K
hMaxi-K is a form of gene therapy using a plasmid vector that expresses the hSlo gene, that encodes the alpha-subunit of the Maxi-K channel. It has undergone phase I safety trials.
- Ginseng
A double-blind study's results show evidence that ginseng is better than placebo.
- Enzyte
Enzyte is a product that has been advertised by saturation coverage on television channels such as CourtTV. However, the Center for Science in the Public Interest (CSPI) has filed a complaint with the Federal Trade Commission (FTC) about Enzyte for deceptive advertising. It is manufactured by Berkeley Nutritionals, which is alleged to be the subject of an investigation by the Attorney General of Ohio and the defendant in class-action lawsuits for false advertising.
Enzyte is a supplement that claims to increase the male libido or frequency of erections of the penis.
The effectiveness of Enzyte is in dispute. Some medical professionals in fact advise against taking Enzyte, saying that it can lead to damage. The Center for Science in the Public Interest have urged the Federal Trade Commission to disallow further television advertising for Enzyte due to a lack of proper studies supporting claims.
Enzyte is said to contain: ''Tribulus terrestris''; Yohimbe Extract; Niacin; Epimedium; ''Avena sativa''; zinc oxide; maca; Muira Pauma; ''Ginkgo biloba''; L-Arginine; Saw Palmetto. Other ingredients: gelatin, rice bran, oat fiber, magnesium stearate, silicon dioxide.
- Prelox
Prelox is a Proprietary mix/combination of naturally occurring ingredients, L-arginine aspartate and Pycnogenol. In double blind tests carried out by Dr. Steven Lamm at New York University School of Medicine, 81.1% of men overall judged Prelox to be effective in improving their ability to engage in sexual activity. Whilst the supplements should be taken daily, the manufacturers claim that it brings the spontaneity back into ones' love life; unlike other products which must be remembered to be taken a fixed time before sexual activity.
Alternative treatment methods
Numerous alternative therapies are used to improve sexual function. Some include: niacin, zinc, copper, Korean red ginseng root, ginkgo, pine bark, ''Tribulus terrestris'', arginine, ''Avena sativa'', horny goat weed, maca root, muira puama, saw palmetto, and Swedish flower pollen. None of these however have been recognized as effective by the FDA. While zinc deficiency may be a cause of lower testosterone levels in hemodialysis patients, which may benefit from zinc supplementation, such supplements have no effect on the testosterone levels of healthy males who consume a zinc-sufficient diet.
Continuing research
The peptide Tx2-6 from the venom of the Brazilian wandering spider has recently received media attention as a potential prototype for new drugs targeting nitric oxide signaling.
Further Reading
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