Dr Saqib Mahmud MRCP(UK), MRCPS(Glasg), MRCGP

1. ED Dr Saqib Mahmud MRCP(UK), MRCPS(Glasg), MRCGP

2. ED-inability to achieve/maintain an erection sufficient for mutually satisfying intercourse • Incidence- increase with age • 39% men aged 40yrs, 67% age 70yrs • Present worldwide prevalence>150 million men, double in next 25yrs >300 million men by 2025 • Previously thought of inorganic origin, now believed that ED is increasingly due to organic disease

3. Mechanism of erection • Largely a vascular event • In response to sexual stimuli, parasympathetic nervous system dilates cavernosal arteries & relaxes trabecular smooth muscle increased blood flow filing sinusoidal spaces engorge penis (tumescence) compress & stops venous outflow maintaining the erection • Reverse of these events after ejaculation sympathetic activity--.contraction of arteries & trabecular smooth muscle--.venous outflow decompression of venous channels (detumescence)

4. Chemical pathways in penile erection • Most important NO-induced cGMP pathway • Endothelial cells release NO in response to sexual stimuli • NO increases cGMP, which relaxes the corpus cavernosal smooth muscle leading to an erection • Detumescence occurs when cGMP is broken down by an enzyme ‘’phosphodiesterase’’(PDE-5)hence the role of PDE5 inhibitors in maintaining the erection

5. causes • Vascular-endothelial dysfunction, atherosclerosis, htn, hypercholesterolemia • Endocrine-DM, hypothyroidism, hyperprolactinaemia, testosterone deficiency, hormonal imbalance due to hepatic & renal disease • Neurological-MS, CVA, Parkinson’s, Alzheimer’s, spinal cord & brain injuries • Peyronie’s disease- rare inflammatory condition->scaring of erectile tissue->painful erection

6. Drugs->200 commonly prescribed drugs can cause or contribute to ED • Beta-blockers • Diuretics-BFZ, furosemide • ACEI • CCB • LH-RH analogs • Antiandrogens • Benzodiazepines • Alcohol • Illicit drugs

7. Other causes of ED • Pelvic trauma • Radiotherapy • Colorectal, prostate & bladder surgery increases the risk of ED • Vascular leak- veins unable to constrict efficiently during erection • Substance abuse- chronic use of cocaine, marijuana, alcohol, steroids • Excessive use of tobacco-nicotine in tobacco causes contraction of small blood vessels less flow to the region->ED

8. Psychological causes of ED • Depression • Anxiety • Stress • Performance anxiety– anxiety & stress lead to increased production of catecholamine which act as erection inhibitors

9. Assessment – ED as a marker Study of 980 men with ED found; • 18% - undiagnosed HTN • 16% - DM • 15% - BPH • 5% - IHD • 4% - Ca Prostate • 1% - Depression b/w 39 & 64% of males with CVD suffer from ED

10. Physical Assessment • BP • Femoral & peripheral pulses, femoral bruits – vascular abnormalities / PVD • Neurological exam – deep tendon reflexes, bulbocavernosis reflex (gentle squeeze of glans anal contraction), reduced sensation- sacrum, perineum • Visual field defects – prolactinoma, pituitary mass • Gynaecomastia – hyperprolactinaemia • Testicular atrophy- testosterone def, hypogonadism

11. Assessment - contd • Rectal exam – assessment of prostate & sphincter tone • PHQ-9 Questionnaire • FBS • U&Es, LFTs, TFTs • Serum testosterone & SHBG, prolactin

12. Management of ED • PDE5 inhibitors – sildenafil, tadalafil, vardenafil • Sildenafil (1998) - 25mg, 50mg,100mg Taken 1hr before sex, effective up to 4 to 5 hrs, s/e - headache • Tadalafil (2003) – 10mg, 20mg(PRN) 2.5mg, 5mg(once daily-2009) Taken 30 minutes before sex, effective up to 36hrs, s/e - dyspepsia, headache

13. contd • Vardenafil(2003) – 5mg, 10mg, 20mg Taken 25 – 60minutes before sex, effective up to 4 – 5 hrs, s/e – headache, flushing

14. When PDE5 inhibitors don’t work Patient Education • 81% do not take them correctly • Adequate sexual stimulation necessary • Food & alcohol delay & reduce absorption • Some need 6-8 doses before an optimal response occurs • Psychotherapy integrated with pharmacotherapy

15. Prescribing advice • Switch drugs • Optimize dose – increase to max • Patients unresponsive to PRN Tadalafil, consider once daily regime • Combine with other drugs; intraurethral alprostadil with PDE5 inhibitors or with doxazocin (weak erectogenic agent) ideal with BPH+HTN patients

16. Other treatments for ED • MUSE – medicated urethral system for erection, pallet of PGE1(alprostadil) inserted in urethra 15min before sex, lasts 30 to 60min • Can be used up to twice daily • s/e – penile pain, burning (32%) • 43% efficacy compared to intracavernosal route but less complications such as priapism and penile fibrosis with injections

17. Vacuum constriction devices • SOMACorrect Xtra, SOMAerect Response II • One time cost (£160 - £180/-) • Efficacy – 92% regardless of underlying cause of ED • Time to erection onset- 90 to 120 seconds • Time required to terminate erectin <30seconds • No systemic side effects compared to oral Rx

18. Surgical treatment for ED • Penile prosthesis – for patients who probabaly have sufffered physical damage to corpora, renndering other treatments ineffective • Vascular surgery – when ED is due to poor arterial inflow or abnormal venous drainage ( arterial revascularization, ligation of venous incompetence) • Results vary widely but usually poor

19. Testosterone therapy • Only indicated in men whose loss of libido/ ED is due to hypogonadism or documented low testosterone levels • Testosterone deficiency is a rare cause of ED • Administered orally, i/m injections, skin patches or implants