Sexual Health Matters

Erectile dysfunction

Roger A Fisken FRCP, Consultant Physician

Friarage Hospital, Northallerton.

Introduction

The prevalence of erectile dysfunction (ED) varies depending on the population studied and is known to increase with age1,2. For the general male population the Massachusetts's Male Aging Study in 19942 showed that the combined prevalence of all grades of impotence was 54% and the prevalence of moderate or complete impotence in men aged 40 to 70 is about 34.8%. So far as the effect of age is concerned, the MMAS study reported a prevalence of complete ED of 5.1% at age 40, increasing to 15% at age 70. High-risk populations include men with diabetes, a previous spinal cord injury, history of prostatic or pelvic surgery, etc.

Aetiology and associated conditions

Drugs
Any antihypertensive agent can be responsible, especially thiazides and beta-blockers (ED is unusual with CCBs and ACE inhibitors, rare with alpha-blockers). Selective serotonin reuptake inhibitors (SSRIs) and other antidepressants, neuroleptics, spironolactone, digoxin, statins and numerous other agents have been reported to cause ED.

Miscellaneous
Smoking or excessive intake of alcohol can lead to erectile dysfunction. Rarer disorders like hyperprolactinaemia, hypogonadism (primary or secondary), liver disease or haemo-chromatosis are possible aetiological factors.

Men with diabetes or coronary heart disease
Six percent of diabetic men aged 20-24, rising to 52% in men aged 55-59, suffers with erectile dysfunction3. This is due to a complex mixture of small vessel disease (microangiopathy), autonomic neuropathy and large vessel disease. Other associated disorders such as fungal balanitis or phimosis may aggravate the condition. Psychological difficulties related to coping with a chronic disease compound the situation. Many of the known risk factors for coronary heart disease are also risk factors for ED and there is a correlation between the severity of ED and the extent of coronary vessel disease. Cigarette smoking increases the incidence of
complete ED in men with heart disease and hypertension2. There is a weak association with hypertension itself, aside from the known, strong association with use of antihypertensive drugs.
Friarage Hospital Sexual Dysfunction service (Carmel Clinic)
This consists of a team of specialists in the field of erectile dysfunction, namely a consultant physician (RAF), a consultant in clinical/health psychology and a sexual dysfunction counsellor. Meetings to discuss patients and service developments are held fortnightly. Referrals are regarded as team referrals: the team decide which health professional should see each patient. There is a common assessment and management protocol and the meetings provide mutual support and updating.

Assessment of the patient with erectile dysfunction

History:
Exact nature of the problem, gradual vs. abrupt onset, daily shaving? One should also ask about libido and enquire about evidence of depression and the partner’s attitude to the problem. It is important to know what the couple’s expectations of treatment are. Other enquiries include: drugs/medicines?, alcohol? other medical problems? In some cases a detailed psychosexual history needs to be taken. General emotional well-being is routinely assessed using a HAD scale questionnaire.

Examination
General examination: breast enlargement, general health, signs of hypogonadism: loss of body hair, soft or small testes. Blood pressure is determined and we feel for the femoral pulses

Is it organic or psychological in origin?
It is usually both. There may be clues to a major psychological component: these include sudden onset; variable severity; sudden loss of rigidity before penetration; stress in relationship or other personal problems; high scores on HAD scale, especially for anxiety. The presence of normal erections during sleep or in the early morning tends to point to a psychological cause for the patient’s symptoms, though this is not totally reliable.

Preliminary blood tests
Blood glucose, liver function tests and blood levels of testosterone are requested in most cases, especially if libido is impaired or examination suggests hypogonadism. It is not necessary to do full blood counts, urea and electrolytes, thyroid function tests, or serum prolactin levels unless specifically indicated.

Eligibility for NHS treatment

Certain medical conditions make a patient with erectile dysfunction qualify for National Health Service (NHS) free treatment. These conditions include: diabetes, multiple sclerosis, Parkinson's disease, polio, prostate cancer, severe pelvic injury, single gene neurological disease, spinal bifida, spinal cord injury. Others are renal dialysis for chronic renal failure; previous radical pelvic surgery, prostatectomy or renal transplant. Patients who were receiving drug treatment before September 1998 are eligible for NHS treatment. “Severe distress” as defined by a hospital specialist is also a qualifying condition for NHS treatment.

Treatment options

These can be divided into medical (including devices) and psychological; surgical treatments are available but are not commonly used. The medications may be in the form of tablets for oral or sublingual
use, or injections. They include: sildenafil
(Viagra), tadalafil (Cialis), vardenafil (Levitra), apomorphine sublingal (Uprima), intracavernosal injection- alprostadil (Caverject), transurethral alprostadil (MUSE) and vacuum tumescence devices. Testosterone is sometimes used if the serum testosterone is borderline low, especially if libido is impaired.

In the consideration of treating impotence in men with cardiovascular risks, it must be borne in mind that sexual activity is about as strenuous as playing golf or walking a mile in 20 mins.

Specific medications:

Sildenafil (Viagra), Cialis and Levitra
These act on phosphodylesterase 5 within cavernosal tissue to enhance vasodilatation induced by erotic stimulation. They are only active in the presence of sexual arousal. Must be taken at least 45 mins (preferably 60-90 minutes) before sex. These medicines are effective in around 65-70% of cases4. There is no convincing evidence that one is better than the others. Cialis has longer duration of effect (up to 36 hours) and can be taken with food.

Sildenafil
A history of ischaemic heart disease is not a contra-indication to Viagra. Moderate or severe heart disease is a contra-indication to sexual activity. The taking of regular oral or transdermal nitrates is an absolute contra-indication to Viagra use (or that of other PDE5 inhibitors) and the same applies to nicorandil and nebivolol. Caution re concurrent use with alpha-blockers.

Side effects: facial flushing, headache, nasal stuffiness, blue tinge to vision. Tadalafil (Cialis): myalgia and back pain. Starting dose of sildenafil 50mg, regular dose range 25-100mg (150mg occasionally). A high percentage of men with diabetes mellitus will require 100mg.

Apomorphine
Given sublingually - ineffective if swallowed. Acts as dopamine agonist, enhancing activity in the hypothalamus, increasing parasympathetic neural outflow to penile vessels. The main advantages are speed (median time to erection 18 minutes) and compatibility with nitrates.

Action is within the central nervous system: the drug has a high specificity for nuclei in the hypothalamus. There is no significant action outside the CNS. Success rate in producing erection sufficient for intercourse is around 45 to 50% (upto 66% in most mildly affected patients). Dose: 2mg or 3 mg. Adverse reactions to apomorphine: nausea (up to 7), headache, dizziness, yawning, rhinitis, pharyngitis, somnolence. Uncommonly: syncope.

Intracavernosal injection
Alprostadil (Caverject, Viridal): this is the most effective pharmacological therapy available (80-90% successful). The dosage is 5 to 7.5mcg initially (1.25-2.5mcg in neurogenic impotence). Response is within 2-3 min. Increased by 5-10mcg as required. Maximum dose 40mcg; rarely necessary to go above 20mcg. Aim for erection lasting approximately one hour. Adverse reactions of this medication include: bruising, scarring (Peyronie's disease), priapism (prolonged painful erection). The patient should be given clear advice about what to do if an erection lasts for more than 4hrs. A discontinuation rate of around 40% is seen, due to inadequate response, becoming fed up with injections, and lack of spontaneity.

Transurethral alprostadil (MUSE)
This avoids the need for an injection but it is less effective than injection therapy (around 40-50%). It takes 5-10 minutes to work. Adverse reactions include penile pain (32%), urethral burning (12%), urethral bleeding 5%, swelling of leg veins or leg.

Vacuum tumescence devices
These are effective in a high percentage of patients. Manual and electrically operated versions are available. They are now available on prescription for men with qualifying medical conditions. They are however often rejected for aesthetic reasons and also because they interfere with ejaculation.

Testosterone: for hypogonadism
Testosterone is really for the treatment of hypogonadism, and not erectile dysfunction. In most clinics, men with slightly low testosterone levels (7-10) that do not show any improvement in erectile function with other treatments may be offered testosterone.

Meta-analysis suggests5 possible benefit if testosterone clearly low. Testosterone is best given transdermally (Testogel) or by buccal route (Striant). Therapeutic trail should be for a maximum of three months. In men over 50 years of age, a rectal examination should be performed to exclude prostate enlargement and blood levels of prostate specific antigen (PSA) should be determined.

Psychological therapies
A variety of treatments are used, including informal psychotherapy (often including the use of educational books or leaflets), teaching of coping strategies, cognitive behaviour therapy and sensate focus – this last is particularly useful for dealing with performance anxiety. Physical and psychological treatments are often used together.

Surgery
This is usually seen as the treatment of last resort as it is necessary to core out patient's own erectile tissue in order to insert an implant. Costly: £1500 - 3500, payable by patient.

Complications of surgery: Infection (1-10%), “supersonic tip”, extrusion of the prosthesis or erosion into adjacent structures, mechanical failure, altered sensation, penis looks smaller than before.

Conclusion

Erectile dysfunction is a common disorder which may present to doctors in a number of different disciplines. It can have many causes. A systematic and sensitive assessment, from both a physical and a psychological point of view, is important. Cure is not often possible (unless a responsible drug can be withdrawn) but treatment is available for the great majority of sufferers. A combined approach, using the skills of physicians, psychologists and others seems to offer considerable benefit.

References.

1. Kinsey AC, Pomeroy WB, Martin CE. Sexual behaviour in the human male. Philadelphia: WB Saunders Co, 1948.
2. Feldman HA, Goldstein I, Hatzichristou et al. Impotence and its medical and psychosocial correlates: results of the Massachusetts Male Aging Study. J Urol 1994; 151:54-61.
3. McCulloch DK, Campbell IW, Wu FC et al. The prevalence of diabetic impotence. Diabetologia 1980; 18:279-83.
4. Goldstein I, Lue TF, Padma-Nathan H et al. Oral sildenafil in the treatment of erectile dysfunction. N Engl J Med 1998; 338:1397-1404.
5. Jain P, Rademaker AW, McVary KT. Testosterone supplementation for erectile dysfunction: a meta-analysis. J Urol 2000; 164:371-5.