Causes of Erectile Dysfunction and Treatment Options

Erectile dysfunction (ED) is the persistent inability to attain and maintain an erection satisfactory for sexual intercourse, present for at least 3 months.

Prevalence rises steeply with age: about 50% of non-diabetic men over 60, and 55–95% of diabetic men over 60.

Continuation of an active sex life is associated with longevity in both men and women; ED must never be dismissed as normal ageing. In women the parallel problems are vaginal atrophy, low desire, depression and SSRI effects.

Physiology: erection is parasympathetic (S2–S4) and nitric-oxide mediated → cavernosal smooth-muscle relaxation via cGMP; PDE5 degrades cGMP. Detumescence is sympathetic. This is the rationale for PDE5 inhibition.

Vasculogenic (commonest): atherosclerosis, hypertension, dyslipidaemia, smoking, diabetes, endothelial dysfunction, venous leak, pelvic irradiation, Leriche syndrome.

Neurogenic: diabetic autonomic neuropathy, stroke, Parkinson's disease, multiple sclerosis, spinal cord disease, cauda equina, and pelvic or prostate surgery (radical prostatectomy, cystectomy).

Endocrine / hormonal dysregulation: hypogonadism, hyperprolactinaemia, thyroid disease, poorly controlled diabetes.

Local and anatomical: Peyronie's disease, post-priapism fibrosis, phimosis, BPH-related lower urinary tract symptoms.

Drug-related — a particular problem in older patients: thiazide diuretics, spironolactone, beta blockers, cimetidine (all four specifically named in Pathy's), plus SSRIs, antipsychotics, antiandrogens and GnRH agonists, 5-alpha-reductase inhibitors, opioids, and older centrally acting antihypertensives. Always take an alcohol and tobacco history.

Performance anxiety, depression, bereavement and loss of a partner, relationship difficulty, and lack of privacy in institutional or multigenerational settings. Sudden onset, situational failure and preserved nocturnal or early-morning erections suggest a psychogenic component. In practice most older men have a mixed organic and psychogenic picture.

Interview the patient — and the partner where appropriate. Take a full sexual, psychosocial and drug history, and clarify whether the problem is desire, erection, ejaculation or orgasm.

Examination: secondary sexual characteristics, penis (plaques, phimosis), testicular volume and consistency, gynaecomastia, peripheral pulses, blood pressure, digital rectal examination, and a focused neurological examination including perineal sensation and bulbocavernosus reflex.

Investigations: fasting glucose/HbA1c, lipid profile, early-morning total testosterone, thyroid function; add prolactin and gonadotrophins if testosterone is low. Validated assessment: the International Index of Erectile Function (IIEF / IIEF-5).

Specialised tests — nocturnal penile tumescence, penile duplex Doppler, cavernosometry — are available through specialist ED clinics but are usually avoided in older patients, in whom extensive testing rarely changes management.

Step 1 — modify reversible factors: optimise glycaemic, blood pressure and lipid control; stop smoking; reduce alcohol; weight loss and regular exercise; and substitute the offending drug (for example replace a thiazide or non-selective beta blocker — nebivolol and ARBs are more erection-friendly; use bupropion or mirtazapine rather than an SSRI for depression).

Step 2 — psychosexual counselling with the partner involved; general education about age-related sexual change; treat depression and address bereavement.

Step 3 — oral PDE5 inhibitors (first-line pharmacotherapy): Sildenafil 25–100 mg on demand, about 1 hour before intercourse; a fatty meal delays absorption. Tadalafil 10–20 mg on demand or 5 mg once daily; duration up to 36 hours, and it also improves BPH-related LUTS — often the best choice in the older man. Vardenafil and avanafil are alternatives. PDE5 inhibitors are effective in carefully selected older people with diabetes. Start at the lower dose in the elderly, in renal or hepatic impairment, and in men on alpha blockers.

PDE5 inhibitor contraindications and cautions: absolute — any nitrate or nicorandil (risk of profound hypotension), and riociguat. Caution with alpha blockers (separate dosing), recent myocardial infarction or stroke, unstable angina, severe aortic stenosis, hypotension, and retinitis pigmentosa. Side effects: headache, flushing, dyspepsia, nasal congestion, blue-tinged vision (sildenafil), back and muscle ache (tadalafil), and rarely non-arteritic anterior ischaemic optic neuropathy and sudden sensorineural hearing loss.

Step 4 — testosterone replacement where the man is genuinely hypogonadal: it improves libido and may restore responsiveness to a previously failed PDE5 inhibitor. It is not a treatment for ED with normal testosterone.

Step 5 — second-line therapies: intracavernosal alprostadil injection (most effective non-surgical option; warn about priapism), intraurethral alprostadil (MUSE), and the vacuum erection device — particularly valuable in older men on nitrates or anticoagulants and after radical prostatectomy.

Step 6 — penile prosthesis (inflatable or malleable) for refractory ED, with high satisfaction rates. Penile revascularisation is reserved for younger men with isolated post-traumatic arterial insufficiency. Low-intensity shockwave therapy, platelet-rich plasma and stem-cell “restorative” therapies remain investigational and should not be offered as established treatment.