Sexual Dysfunction — Causes, Erectile Dysfunction, PDE5 Inhibitors & Treatment Guide — Symptoms, Causes & Treatment | MyMedicPlus

Sexual dysfunction encompasses any persistent disturbance in the normal sexual response cycle — desire, arousal, orgasm, or resolution — that causes significant personal distress or interpersonal difficulty. It affects approximately 30-40% of men and women at some point in their lifetime, increasing substantially with age and comorbidities. In men, the major disorders are: erectile dysfunction (ED — inability to achieve or maintain an erection sufficient for satisfactory sexual intercourse, affecting 50% of men aged 40-70); premature ejaculation (PE — ejaculation occurring consistently before or within 1 minute of vaginal penetration, the most common male sexual disorder — 20-30%); delayed ejaculation; and hypoactive sexual desire disorder. In women: female sexual interest/arousal disorder (FSIAD — persistent lack of interest or arousal, affecting 10-20%); genito-pelvic pain/penetration disorder (GPPPD — encompassing vaginismus and dyspareunia, affecting 10-15%); female orgasmic disorder; and medication-induced sexual dysfunction (particularly SSRI-induced anorgasmia — affecting 30-50% of SSRI users). Sexual dysfunction is often the first manifestation of serious cardiovascular disease, diabetes, or hypogonadism in men — and must trigger investigation beyond symptomatic treatment.

Erectile dysfunction causes: vascular (the most common organic cause — endothelial dysfunction and atherosclerosis reduce cavernosal blood flow; ED precedes coronary artery disease by 3-5 years in 50% of men with ED and CV risk factors — making ED a major cardiovascular risk marker); diabetes mellitus (autonomic and somatic neuropathy plus vascular disease — ED present in 50-75% of diabetic men); hypogonadism (low testosterone — reduces libido and may impair cavernosal smooth muscle relaxation); medications (antihypertensives — particularly beta-blockers and thiazides; antidepressants — SSRIs, SNRIs, tricyclics; antipsychotics; 5-alpha-reductase inhibitors; antiandrogens; opioids); neurological disease (Parkinson's disease, multiple sclerosis, radical prostatectomy nerve injury, spinal cord injury); psychological factors (performance anxiety, depression, relationship difficulties — especially as cause in younger men). Premature ejaculation: neurobiological — reduced central serotonin (5-HT2C) receptor activity; hypersensitivity of penile glans (low IELT threshold); genetic predisposition. Psychological causes are more important in secondary PE. Female sexual dysfunction: hormonal (oestrogen deficiency — menopause, lactation, PCOS with anti-androgen therapy, combined oral contraceptive pill may reduce free testosterone); medication (SSRIs — anorgasmia, reduced desire; antipsychotics — hyperprolactinaemia; OCP — free testosterone reduction); psychological (relationship factors, body image, history of sexual trauma); gynaecological pathology (endometriosis, vulvodynia, lichen sclerosus, vaginitis — pain during intercourse).

Erectile dysfunction: inability to achieve an erection suitable for penetration; erections that cannot be maintained throughout intercourse; absent or reduced morning erections (loss of nocturnal penile tumescence suggests organic ED; preserved morning erections suggest psychogenic ED). International Index of Erectile Function (IIEF-5): validated 5-item questionnaire; maximum score 25; mild ED: 17-21; moderate: 11-16; severe: under 11. Premature ejaculation: ejaculation consistently occurring within 1 minute of vaginal penetration (lifelong PE) or significantly earlier than desired with negative impact on distress and interpersonal difficulty (acquired PE); measured by intravaginal ejaculatory latency time (IELT). Hypoactive sexual desire: reduced frequency of sexual thoughts, fantasies, and desire for sexual activity causing distress — distinct from asexuality; important to distinguish from secondary causes (depression, relationship factors, medication). Female genito-pelvic pain: superficial dyspareunia (at vaginal entrance — vulvodynia, vestibulodynia, vaginismus); deep dyspareunia (pelvic pain during penetration — endometriosis, PID, pelvic congestion); vaginismus (involuntary contraction of the vaginal introital muscles preventing penetration — associated with anxiety and phobic response).

Detailed sexual and medical history: type of dysfunction, onset (lifelong versus acquired), situational versus generalised, associated symptoms, relationship context, medical comorbidities, and a full medication review. Validated questionnaires: IIEF-5 for erectile dysfunction severity; Premature Ejaculation Profile (PEP) for PE; Female Sexual Function Index (FSFI) for women. Physical examination: genital examination (penile fibrosis — Peyronie's disease; testicular atrophy — hypogonadism; vulval pathology — lichen sclerosus, vestibulitis); blood pressure, body mass index, peripheral pulse assessment (vascular ED). Laboratory investigations in men with ED: fasting glucose and HbA1c (diabetes); total testosterone (morning sample — hypogonadism; if low, repeat and add LH, FSH, prolactin); full lipid profile; renal and liver function; PSA if aged over 50. Nocturnal penile tumescence (NPT) monitoring (RigiScan): distinguishes organic from psychogenic ED — preserved nocturnal erections with no functional erections suggests psychogenic cause. Duplex ultrasound of the penis after intracavernosal papaverine injection: assesses cavernosal arterial flow and venous leakage — reserved for vascular assessment before surgery. In women: hormonal profile (FSH, LH, oestradiol, testosterone, prolactin, TSH); pelvic examination and colposcopy for pain disorders; gynaecological imaging (ultrasound for endometriosis).

Erectile dysfunction: first-line — PDE5 inhibitors (phosphodiesterase-5 inhibitors): sildenafil (Viagra, 50-100 mg taken 30-60 minutes before intercourse — effective in approximately 70% of men); tadalafil (Cialis, 10-20 mg as-needed or 5 mg daily for continuous therapy — longest duration of action, 36 hours, allowing spontaneous sexual activity); avanafil (200 mg — fastest onset, 15 minutes); vardenafil. Contraindicated with nitrates (risk of severe hypotension). If PDE5i fail: vacuum erection devices (VED); intracavernosal injection (alprostadil, papaverine ± phentolamine); intraurethral alprostadil (MUSE); penile implant (inflatable or malleable prosthesis — highest satisfaction rates). Premature ejaculation: dapoxetine (30-60 mg, taken 1-3 hours before intercourse — short-acting SSRI; approved for PE in Europe; reduces IELT 3-fold); regular daily SSRIs (paroxetine — longest IELT-prolonging effect; sertraline, fluoxetine); topical anaesthetic sprays or creams (lidocaine 9.6% or benzocaine 7.5% spray — applied to glans 15-20 minutes before intercourse, washed off before penetration — ProLong, Dynamo); pelvic floor exercises. Hypogonadism-related SD: testosterone replacement (gel, patch, injection) — significantly improves libido and may improve ED. Female sexual dysfunction: psychosexual therapy (CBT-based — efficacious for FSIAD, vaginismus); pelvic floor physiotherapy with graduated vaginal dilators for vaginismus/GPPPD; oestrogen therapy (local vaginal oestrogen cream or pessary — treats genitourinary syndrome of menopause, improving lubrication, reducing dyspareunia); flibanserin (Addyi — FDA-approved for HSDD in premenopausal women; modest benefit; requires alcohol avoidance); ospemifene (SERM for dyspareunia); topical testosterone (emerging evidence for FSIAD in postmenopausal women).

Erectile dysfunction is a significant cardiovascular risk marker — studies show that ED precedes cardiovascular events (angina, MI, stroke) by 3-5 years in 50% of affected men with cardiovascular risk factors; ED itself is equivalent to a 10% additional Framingham cardiovascular risk. Therefore untreated or unrecognised ED may represent a missed opportunity to implement primary cardiovascular prevention. Psychological impact: ED, premature ejaculation, and female sexual dysfunction all cause significant depression, anxiety, social withdrawal, relationship breakdown, and loss of self-confidence — with bidirectional relationships between mental health and sexual dysfunction. Relationship distress: sexual dysfunction is a leading cause of relationship breakdown, particularly when untreated. Male sexual dysfunction — particularly ED — may be the only presenting symptom of serious hypogonadism (pituitary tumour, testicular failure), diabetes, or hypertension — missing the diagnosis delays treatment of these conditions. Vaginismus, untreated, prevents contraceptive examinations, smear tests, and gynaecological procedures — with significant impact on reproductive health.

Optimise cardiovascular risk factors: erectile dysfunction is primarily a vascular disease — the same lifestyle interventions that prevent cardiovascular disease prevent and improve ED. Control diabetes (achieve HbA1c below 53 mmol/mol), treat hypertension (target below 130/80 mmHg), achieve optimal LDL (below 2.0 mmol/L), quit smoking (smoking doubles ED risk), achieve a healthy BMI (obesity is an independent ED risk factor — weight loss of 10 kg improves IIEF score significantly), and exercise regularly (aerobic exercise 30 minutes, 4 times weekly improves endothelial function and reduces ED severity by 40-60% in some RCTs). Avoid medications that cause sexual dysfunction when alternatives exist: review beta-blockers, thiazide diuretics (consider substituting nebivolol or ACE inhibitor), SSRIs (consider switching SSRI to mirtazapine or bupropion if SSRI-induced sexual dysfunction is problematic), and cimetidine. Limit alcohol (above 21 units/week impairs testosterone production and erectile function). Psychosexual health: open communication between partners, early professional help for relationship difficulties, and avoidance of performance anxiety — psychosexual therapy is highly effective when psychological factors predominate.

See a GP for any sexual dysfunction causing personal distress or relationship difficulty — particularly erectile dysfunction in a man under 60, which requires investigation for cardiovascular disease, diabetes, and hypogonadism rather than just symptomatic PDE5 inhibitor prescribing. Request urgent or same-day GP review for: priapism (a prolonged erection lasting over 4 hours unrelated to sexual stimulation — a urological emergency requiring immediate treatment to prevent permanent erectile tissue damage; administer ice, exercise, and go to A&E if it persists over 4 hours); and sudden onset ED or sexual dysfunction after starting or changing a medication. See a GP for: hypoactive sexual desire with fatigue, weight gain, or depressive symptoms (possible thyroid disease or hypogonadism); dyspareunia or pelvic pain during intercourse (possible endometriosis, vulvodynia, or pelvic inflammatory disease); and vaginismus preventing penetration (pelvic floor physiotherapy and psychosexual therapy are highly effective and should be offered promptly).