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TREATMENT
General management
The initial management should be to advise patients to reduce their alcohol
intake and smoking. Diabetic control should be monitored and it may be possible
to adjust the existing drug regimen, although changing one anti hypertensive
drug to another seldom improves erectile function. Almost all men with erectile
dysfunction will be affected psychologically, even if the cause is organic. In
severe cases sexual counselling is important and it is preferable to also
involve the patient's partner. Counselling helps to reassure the couple and ease
tension in the relationship. Temporary erectile dysfunction is not uncommon and
does not usually require pharmacological intervention.
Drug therapy
Most men consider this the treatment of choice. Yohimbine has a weak alpha
adrenoreceptor blocking ability, and has not been very effective in many
patients. Oral phentolamine is being used in other parts of the world, and
according to clinical trials is an effective oral treatment. Apomorphine (a
dopamine receptor agonist) is currently being considered by Medsafe for
registration as an oral treatment for erectile dysfunction in New Zealand. It
obtained FDA registration and is a treatment being used by doctors in the US.
Sildenafil is the first effective oral drug that has been approved for the
treatment of erectile dysfunction in New Zealand.
Further preparations with similar mechanism of
action are likely to become available now the basic biochemical mechanisms of
erection physiology are better understood.
a. Sildenafil (Viagra)
Sildenafil is a type 5 p hosphod iaste rase
inhibitor that prevents the intra corpeal breakdown of cyclic GMP. It was
originally developed for the treatment of angina pectoris and was found to
increase the number of erections in patients undergoing clinical trials. It has
now been Ncenced for use in the treatment of erectile dysfunction for men with
organic and psychological aetiologies.
Sildenafil is rapidly absorbed after oral
administration. It is taken 60 minutes before anticipated sexual activity and
its effects last is taken approximately four hours. I have found that in many
patients the window of opportunity can be as long before as eight hours. The
drug is available in three strengths, ie, 25, 50 and 10Orng. Most patients seem
to do well on 50 mg. Taking the drug itself does not provoke an erection as
such, but enhances the continued relaxation of the cavernous smooth muscle
initiated by the release of endogenous nitric oxide with an improved quality of
erection. Sildenafil is contraindicated in men taking nitrates due to the risk
of hypotension. Clinical trials have shown it is efficacious in 40-80 per cent
of men, depending on the aetiology of their dysfunction. It has a relatively low
side effect profile and the side effects consist mainly of headache (16 per
cent), facial flushing (10 per cent) and dyspepsia (7 per cent). A mild
transient disturbance of colour vision and also increased sensitivity to light
or blurred vision has been found in 3 per cent of men. The side effects are all
dose related. It is important not to take sildenafil with any fat-containing
foods, and simultaneous intake of alcohol can also affect the absorption. It is
also advisable not to split tablets, because the chemical deterioration of the
unused half can make it less effective.
Transurethral administration of alprostadil
Alprostadil was first licensed for use in the treatment of erectile dysfunction
by intracavernous injection. This drug has been incorporated into a pellet that
can be given by intraurethral application. Alprostadil, the synthetic
reproduction of the naturally occurring prostaglandin E1 acts by initiating an
erection. In contrast to sildenafil ' it initiates the relaxation of cavernous
smooth muscle to bring about an erection. This is a device-based treatment.
Patients need to be instructed in the use of MUSE, which is introduced into the
urethra with a disposable applicator. The patient needs to pass urine beforehand
to act as a natural lubricant and to facilitate the absorption of the drug.
Absorption is also facilitated by the patient rolling his penis between the
palms of his hands. Some patients find that a constrictive ring around the base
of the penis enhances efficacy. The erection takes about 10 minutes to develop
and the dose range varies between 125 and 1000pg. I find most patients get good
results from 550pg and occasionally 1000pg. In clinical trials about 43 per cent
of patients who tried MUSE were able to have intercourse at least once with this
treatment but, as with other invasive methods, there is a high dropout rate. The
most common side effect is penile pain (30 per cent), urethral burning (12 per
cent) or minor urethral bleeding (5 per cent). Systemic side effects are
uncommon. For those patients who elect to use MUSE, I usually administer the
first dose in my rooms. I make sure the patient knows exactly what to do, and it
also gives me an idea of its efficacy and whether to adjust the dose. I also
give these patients a video (available from the pharmaceutical company) which
takes the patient through the application process step by step.
c. Vacuum devices
This treatment form has the merit of being non-invasive. The disadvantage is it
requires some degree of skill in handling, and applying the treatment can take
some time. They should only be used for 30 minutes at a time, and usually
require a willing and cooperative partner. These devices create a vacuum around
the penis and blood is drawn into the corporal spaces. A band is slipped off the
plastic cylinder around the base of the penis to maintain penile tumescence
without rigidity in the crura. There are few side effects, although there is
some degree of discomfort and the penis feels cold. Ejaculation is usually
blocked and some men find this makes orgasm less satisfactory. Bruising can
occur in 10-15 per cent of men. Vacuum devices are useful in older men with
stable relationships and where other treatment options are contraindicated or
less effective. They may also be used to enhance the result of pharmacotherapy.
The use of a constrictive ring without the involvement of a vacuum device has
been effective in some men to augment the effects of pharmacotherapy.
d. Intracavernosal injection therapy
Intracavernosal injection therapy was started in 1982 by Dr Vigra when he used
papaverine to initiate the erection process in men suffering from erectile
dysfunction. Self-injection therapy requires some specialist knowledge by the
treating doctor, who must also be skilled in treating priapism should it occur.
This treatment used to be regarded as the standard one for erectile dysfunction
and it was used for both diagnostic and therapeutic reasons. Patients need to be
taught how to perform self-injection, and the dose needs to be calculated
carefully to avoid prolonged erections. I teach my patients by demonstrating on
a latex model, and once again make use of videos. I encourage them to use an
auto-injector, as most find it difficult to insert the needle into the
appropriate site in the corpus cavernosum. In order to calculate the dose and
consider which of the different combinations to use, I administer a standard
test dose to all my patients. I also perform a vascular Doppler on the dorsal
penile artery before, and 15 minutes after, giving the test dose. Erection
occurs after 10 minutes and may be enhanced by sexual stimulation. The incidence
of complications varies with the different pharmacological agents; some pain is
not uncommon, but long term complications are limited to priapism and/or penile
fibrosis.
Drugs for intracavernous injection
Alprostadil: This is the most widely used agent. It is effective in 70-80 per
cent of patients and has a low incidence of side effects. Penile pain occurs in
15-50 per cent of patients but is often not severe enough to discourage
intercourse. The dose range is 5-20pg but I sometimes increase it further, or
use a combination with papaverine and or phentolamine. Priapism occurs in about
1 per cent of cases. Papaverine: This was the first agent for general use. It
always pays to use this drug in combination therapy because of its high
incidence of priapism if used in high doses on its own. It also has the ability
to cause penile fibrosis if used over a long period of time. Papaverine and
phentolamine mix-ture: This is still used in many countries. It is more
effective than papaverine alone and the chance of developing priapism is less
than with papaverine alone. Trimix (papaverine, alprostadil, phentoiamine): This
mixture was introduced to treat those patients who responded poorly to
papaverine alone or in combination with phentolamine or alprostadif alone.
e. Surgery
3.
Surgery is rarely performed these days as a treatment for erectile dysfunction.
The following are indications for surgery:
Arterial reconstruction in young men under the age of 40 with a proven
post-traumatic arterial lesion on a selective angio-gram and with no risk
factors such as smoking, hypertension or diabetes. The inferior epigastric
artery is rerouted and anastomosed with the dorsal penile artery/vein. Careful
selection of patients gives a 65 per cent one-year success rate. Surgery for
veno-occlusive dysfunction. This is sometimes successful in cases of congenital
focal abnormalities, but has a low success rate in the presence of vascular risk
factors. Penile prosthesis. This type of surgery is only indicated in a select
group of patients who fail to respond to any of the less invasive treatment
options. A prosthesis does not restore a normal erection, but makes the penis
rigid enough for sexual intercourse.
CONCLUSION
Men with erectile dysfunction should be encouraged to seek medical advice.
Erectile dysfunction is more common in men over the age of 40 with risk factors
such as chronic illness, pelvic trauma, pelvic surgery, alcohol abuse, cigarette
smoking, systemic atherosclerosis and diabetes. There are various treatment
forms available and the list of options will increase in the near future. Most
patients would prefer to regain the ability to have a normal, spontaneous
erection. This is only possible when the problem is mainly psychological,
drug-related or hormonal. All patients can benefit from counselling and it is
also important to remember some patients prefer the option of a satisfactory
nonpenetrative sexual relationship. It is customary to start with non-invasive
therapy, and limit the more invasive forms of treatment to those with specific
indications.
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