1. treat or eliminate known causes 2. oral PDE-5 inhibitors 3. intraurethral or intracavernous tx 4. possible combo therapy 5. penile prosthesis

scott p3 Flashcards by Sara Vangjeli

What is the #1 risk factor of ED

age

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etiology of ED…

diabetes, hypetension, CAD, MS, Parkinson’s, stroke, low testosterone levels (rarely)

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physical etiology of ED

injury
surgeries
meidicines
radiation

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drug-induced sexual dysfunction

Antidepressants
SSRIs- up to 70%
antihypertensice agents
estrogens/ anti-androgens
5-alpha reductase inhibitors
cancer chemotherapy

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unhealthy lifestyles

reason for ED
excesive EtOH
tobacco smoking
obesity
inadequate sleep
stress

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erection 101- three subtypes

psychogenic, reflexogenic, nocturnal

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MOA of erection

intitated by PARASYMPATHETIC division of ANS; suppressed by sympathetic division
upon sexual stimulation, ACH is released which cases releases of NITRIC OXIDE is released from the NANC neurons in the penis
Sexual stimulation can be tactile stimulation of the penis or from psychogenic stimulation secondary to audiovisual or fantasy

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what does NO do

NITRIC OXIDE activates guanylate cyclase which converts GTP to cGMP

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what happens after GTP converts to cGMP

elevated levels in cGMP results in Ca++ releae and produces smooth muscle relaxtion in the penis

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Smooth muscle in the penis leads to…

arterial blood flooding chambers in the penis

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when there is pressure in the flooding chambers….

the veins in the penis squeeze shut preventing draining of blood

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Once the penis is filled with blood….

ERECTION!!!!

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anatomy and pathophys

oxygen is important for penile health
3-6 nocturnal erections/night
Nocturnal penile tumescence
frequency influenced by test. levels
important diagnostic information
controled by sacral nerves

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treatment of ED

treat or eliminate known causes
oral PDE-5 inhibitors
intraurethral or intracavernous tx
possible combo therapy
penile prosthesis

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Oral therapies for ED

first line tx of choice for most pts
promotes smooth muscle relaxation in the penis by inhibiton of phosphodiesterase-5
inhibit the hydrolyzation of of cGMP to 5’ GMP
sexual stimulation is required

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Why are PDE-5 inhibitors for popular?

“male sexual enhancement”
enhanced development and MAINTENANCE of erection
more rigid and longer lasting
decrease refractory period between erections

Why are PDE-5 inhibtors so popualr

easy to use
they work
now much more affordable and easier to obtain

generic formulation of PDE-5 inhibitors

Sildenafil and tadalafil

Sidenafil

25,50, 100 mg
starting dose 50 mg
onset 30-60 min
duration 4 hours
take on empty stomach

vardenafil

2.5,5,10,20 mg
starting dose 10 mg
onset 30-60 min
duration 4 hours

tadalafil

2.5,5,10,20 mg
starting dose 10 (2.5-5 mg if daily)
onset 60 min
duration 36 hrs

how should we adjust the dose

try a larger dose but only to produce an erection that lasts no longer than 1 hour

Drug interactions with PDE-5 inhibitors

CYP3A4, prolongs the effect of the drugs (grapefruit juice)
Food delays the absorption

SILDENFIL STARTING DOSE

25 mg

possible side effects of PDE-5 inhibitors

most are mild and self limiting headache flushing hyspepsia nasal congestion NAION (non-arteritic ischemic optic neuropathy) -sudden vision loss

Precautions of using PDE-5 inhibitors

patients on oral or transdermal nitrates DO NOT USE drops blood pressure bad for heart health

If patient is on an alpha-blocker...

start the PDE-5 inhibitor on lower dose

report erections that last longer than....

4 HOURS

Pt education

taking on demand vs daily dosing 1-2 hours prior to intercourse dosing with respect to meals report erections that last >4 hours report any visual or hearing complaints report palpitations or dizziness avoid nitrates

pulmonary hypertention

can be treated by a PDE-5 inhibitor Sildenafil (revatio) 20 mg PO TID Tadalafil: adcirca 40 mg PO once daily

Vacuum erection devices

very effective slow onset base ring used to maintain erection $300-$500 bruising; numbness pain from bands blue, cool penis AVOID IN SICKLE CELL PTS

transurethral suppositories

alprostadil pellets- MUSE more acceptable to many pateints than injection less effective than injection onset within 5-10 minutes penile pain 30%; burning 10%

directions for use of a transurthtral suppositories

urinate first insert suppository roll penis for 10-30 sec max of 2 doses per day

Alprostadil injection

Intracavernosal injections DOC if pts fails PDE-5 inhibitors may be best for neurogenic ED onset 5 minuts duration 1 hour injection technique but be taught no sexual stimulation required

potential side effects of alprostadil injection

some local irritation penile pain risk of priapism cavernosal plagues or areas of fibrosis

priapism

a condition in which a penis remains erect for hours in the absence of stimulation or after stimulation had ended

etiology of priapism

drugs sickle cell disease pelvic tumors and infections leukemias genital trauma cause is unknow approx 1/3 cases Ischemic (painful) vs. non-ischemic (not painful)

Drug induced priapism

ed drugs antidepressants like bupropion, trazadone, floxetine, sertraline, lithium antipsychotics like clozapine and chorpromazine anticoagulants like heparin and warfarin cocaine etoh, prazosin, hydroxyzine

tx of priapism

erection >4 hours pain phenylephrine 0.1-1 mg blood apiration saline irrigation tx non-ischemic with cold packs and compression