27th June 2023

Erectile Dysfunction

Definition

NICE defines erectile dysfunction (ED) as the persistent inability to attain and maintain an erection sufficient to permit satisfactory sexual performance. The causes are usually multifactorial but can be considered as primarily organic or primarily psychogenic. Medications may also contribute. ED is a common disorder with incidence and prevalence increasing with age. ED affects the physical, emotional, and psychosocial health of the sufferer, and interestingly there is also a significant increase in the risk of cardiovascular disease (CVD) among men with ED.

Organic causes

Vascular causes account for most organic ED presentations. Risk factors are the same as for the development of CVD and include hypertension, dyslipidaemia, and diabetes mellitus. Major pelvic surgery can also affect blood supply, including prostate-cancer surgeries and radiotherapy to the pelvis or retroperitoneum.

Neurogenic causes may be central or peripheral. Central causes include degenerative diseases, such as Parkinson’s disease, stroke, trauma, and central nervous system tumours. Peripheral causes include diabetes and chronic renal disease.

Hormonal imbalance can cause ED; hyperprolactinaemia, Cushing’s and hyper/hypothyroidism are all potential causes to rule out.

Psychogenic causes

These can be considered as generalised, for example, the inability to become aroused, or situational, where it may be partner or time specific. Stress and psychiatric illness, for example, anxiety or depression, all contribute to the development of ED.

Common drug related causes

A drug cause should be considered if erectile dysfunction began within two weeks of starting a new medication; on stopping the drug, ED symptoms should resolve; however, many of the medications are essential to treat or prevent serious illness, so it may not always be practicable to stop treatments.

Potential drug causes of ED include:

• Antihypertensives such as beta-blockers, verapamil, and clonidine
• Antidepressants, including SSRIs and tricyclics
• Antiarrhythmics: digoxin and amiodarone
• Diuretics, especially thiazide-type and spironolactone
• H2-antagonists such as cimetidine and ranitidine
• Recreational drugs, including alcohol, cannabis, heroin, cocaine, methadone, and anabolic steroids.

Pharmacological Management

For most men, phosphodiesterase-5 (PD5) inhibitors, as required, are appropriate – these can now be bought over the counter in the UK, as well as prescribed. They should be avoided in men with severe coronary artery disease, those who have had a stroke in the last six months or myocardial infarction in the last three months. They are not suitable for men who have severe hepatic impairment, and the dose should be reduced for those with significant renal impairment. There are many drug interactions, including with cytochrome p450 inhibitors, as clearance of PD5-inhibitors relies on this pathway. Concurrent use of nitrates is an absolute contraindication due to the risks of unpredictable hypotensive episodes. If a man develops chest pain after taking a PD5 inhibitor organic nitrates cannot be given for at least 12 hours (depending on PD5 inhibitor taken).