Case Discussion for Pharmacy Undergraduates Erectile Dysfunction By. Dr. Lokesh Shetty MPHARM – Pharmacology Lecturer- RCsDP
A 72-year-old male patient complains of erectile dysfunctionon a routine office visit. He was married for 30 years when his wifedied of cancer few years ago. He was depressed initially and oftenthought of his late wife. On the insistence of his children and friends,he began to socialize again and recently met an attractive female,with whom he started an intimate relationship. However, hefailed to obtain sufficient erection at the momentsthat mattered. He feels very frustrated and seeks help. He has ahistory of coronary artery disease with a myocardialinfarction five years ago, well-controlled hypertension for thelast ten years, diabetes mellitus for 15 years, benign prostatichypertrophy, exertional angina, and hyperlipidemia. He istaking the following medications: enalapril; aspirin; isosorbidemononitrate; doxazosin; lovastatin; and insulin glargine. His physicalexamination is unremarkable except for diminished peripheral pulses,and he appears to be in good spirits. Doctor prescribe him forSildenafil Citrate.
ObjectiveDefine erectile dysfunction (ED)Discuss the most common causes of EDReview the treatment options
Sexual Response and Ageing in Men: Sexual response begins to slow down while ageing (Afterthe age of 30) & Sexual inability is common in Geriatrics. Stages of sexual response also change with aging. There is delayed erection, decreased tensing of thescrotal sac, and loss of testicular elevation during theexcitement phase. Prolongation of plateau stage, and decrease in pre-ejaculatory secretion. An aging man may find that it takes longer to achieve anerection. Quick loss of erection after orgasm, or longer time neededfor next erection.Complete Erectile Dysfunction ?
ERECTILE DYSFUNCTION The inability to achieve and maintain a penile erectionsatisfactory for sexual intercourse ---- Does not includeejaculation disordersERECTION ? The erection of the penis is its enlarged and firm state. It depends on a complex interaction of psychological,neural, vascular and endocrine factors. The penis is formed by erectile tissues (corporacavernosa) and involuntary muscles. Penis has rich blood supply. Penis is supplied by Autonomic & Somatic nervoussystem
Penile erection Occurs when blood flow increases &Outflow is obstructed. Thus spongy erectile tissues will befilled with blood (due to arteriolar dilatation & venoconstriction). Thus erection results in swelling and enlargement of the penisSmooth Muscle Relaxation & Erection:Erection is caused by vasorelaxation in the arteries andarterioles supplying the erectile tissue. This increases penileblood flow. Relaxation of trabecular smooth muscle causesfilling of the sinusoids. This compresses the plexuses ofsubtunical venules between the trabeculae and the tunicaalbuginea, occluding venous outflow and causing erection.
Mechanism of Smooth muscle relaxation:Release of Neurotransmitters-nitric oxide (released bothfrom nitergic nerves and from endothelium)NO endogenous activator of soluble guanylateCyclase Thus Conversion of GTP to cGMP - erectionBreakdown of cGMP by PDE type 5 - Detumiscence
Classification of ED:PsychogenicNeurogenicEndocrinologicArteriogenicCavernosal (Venogenic)Drug-inducedErectile dysfunction associated with aging,systemic disease & others
Pharmacological Treatment:1. Phosphodiesterase Enzyme (PDE) Inhibitor:Sildenafil Citrate, Tadalafil, Vardenafil.Sildenafil, the first selective Phosphodiesterase type Vinhibitor (Phosphodiesterase metabolizes the cGMPformed, Thus diminish intracellular cGMP concentration). The resulting increase in cytoplasmic cGMP mediatesvasodilation via activation of protein kinase G.Indications: Psychogenic ED Mild vasculogenic EDNeurogenic ED
Side effects:Headache Flushing Dyspepsia Nasal congestionVisual disturbances Pianism2. Alpha 2 adrenoreceptor antagonistYohimbine SE Side effects: increase blood pressure,tachycardia, anxiety3. Dopamine agonistApomorphine SE Potent Emetic4. Alpha blockerPhentolamine40% efficacy in mild organic EDSide effects: nasal congestion, tachycardia, dizziness,hypotension
5. Prostaglandin E Alprostradil Vasodilator Transurethral (Insert through urethra) Erection occurs 10-15 minutes laterErection lasts 30-45 minutesSide effects: Pain, bleeding, priapism (painfulcondition in which erect penis does not return to itsflaccid state)
Non – Pharmacological:1. Vacuum constriction deviceMechanism of Action:Penis placed in plastic tubeAir evacuated from the tubeBlood trapped in penis with constricting ring2. Penile Prosthesis Surgery & placing pump Patients who have failed other therapies