Flashcards in Drug Treatment of Urogenital Disease Deck (22):
Define erectile dysfunction.
Persistent inability to achieve or maintain erection sufficient for satisfactory penetration of sexual satisfaction
Stats about erectile dysfunction?
Age related; 39% men>40yrs, 55% men>70yrs.
Psychogenic, organic of mixed aetiology.
What are risk factors for erectile dysfunction?
1) Disease - diabetes, CV disease (interact with vascular function), depression (psychogenic)
2) Drugs - alcohol, thiazides, antidepressants, sedatives.
3)Trauma - spinal cord injury, prostatectomy.
Explain the physiology of an erection.
2) Activation of parasympathetic nerves - releasing NO, causing relaxation of blood vessels.
AND...inhibition of sympathetic nerves removing NA induced (alpha1) contraction of BV.
3) Blood enters corpus cavernosum and corpus spongiosum causing them to swell; swelling occludes the venous outflow causing engorgement and erection.
4) Following orgasm, the parasympathetic nerves re inhibited and the sympathetic nerves are activated; the release of NA contracts the CC/CS and allows detumescence.
Explain what happens at the nitergic neuroeffector junction.
In parasympathetic nerve: Larg --nNOS (Ca++ dependant)--> Lcit + NO.... NO to smooth muscle and activate guanylyl cyclase. GTP --gunaylyl cyclase--> cGMP which causes relaxation. cGMP is broken down to GMP by PDE5.
Selective PDE5 inhibitor.
Requires sexual arousal to provide effect
Pleak plasma levels after 30-120mins
25-100mg, 1hr, prior to sex.
t1/2 = 4 hours
metabolised by cytP450
SIDE EFFECTS: visual disturbances/blue tinge (PDE6), headache, flushing, nitrate interactions.
What are 2 newer PDE5 inhibitors?
Vasodilator. Intracavernous injection, painful.
Vasodilator, weak PDE inhibitor - intracevernous injection - pain at site of injection.
Symptholytic - alpha antagonist!
BUT can cause Priapism. Painful, prolonged erection for more than 4 hours - if great than 6, treat...aspiration of blood, administration of sympathomimetics - phyenylephrone (alpha ag)
Explain a central treatment for Erectile Dysfunction.
Apomorphine - dopamine agonist.
Sublingual administration - but vomitting.
Give some example of female sexual dysfunction.
Hypoactive sexual desire, sexual arousal disorder, orgasmic disorder, sexual pain disorder.
What is urinary incontinence?
Demonstrable involuntary loss of urine - affects 10% of women.
What is stress incontinence?
Involuntary loss of urine in the absence of detrusor contraction.
- pressure inside the bladder > pressure applied by urethra.
- displacement of urethra downwards through the pelvic floor and out of abdomen.
- caused by weakening of pelvic floor muscles following childbirth.
-loss of urine during coughing, sneezing, laughing.
What is urge incontinence?
Persistent need to urinate due to detrusor over activity (due to inflammation/irritation).
Treatment of stress incontinence?
Drugs used to support non-pharmacological approaches - eg pelvic floor exercises/bladder management.
Drugs aim to increase urethral pressure.
- alpha 1 agonist - ephedrine.
- NA uptake inhibitor - duloxetine
or...oestrogen therapy to build up the urethral mucosa.
Treatment of urge incontinence?
Decrease detrusor activity (contracts via ACh on M3 receptors)
M3 antagosnist - oxybutnin
BUT - dry mouth, constipation, headaches and nausea.
Explain bengin prostatic hyperplasia.
Most frequence cause of neoplasm - caused by excessive growth of a gland.
50+ yrs > 85%
Enlargement of prostate causes bladder outflow obstruction and decreased urine flow....or conversely - urge incontinence.
Explain growth and contraction of the prostate.
Growth - androgen dependent. (DHT)
Contraction - sympathetic.
Inhibits 5 alpha reductase (converts testosterone to DHT). Decreases DHT levels and prostate size (20%) and decreased need for surgery by 50%!
Alpha 1 antag - inhibits contraction, relieves pressure on urethra.
BUT postural hypertension, dizziness etc.
Tamsulosin - alpha 1A anta - less side effects and only take once daily!