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Erectile dysfunction
erectile dysfunction
22
Accounting
Pre-School
11/03/2014

Additional Accounting Flashcards

 


 

Cards

Term
Erectile Process
Definition

When muscles of arteries and sinusoids relax (erectile tissue fills with blood at arterial pressure); compression of plexus of subtunical arteries reduces venous outflow

 

Demutescence occurs with reversal of this process

Term
Central nervous input is absolutely necessary for
Definition
overall tone of cavernosal artery
Term
NANC pathway
Definition
Noradrenergic noncholinergic releases NO -- activates guanylyl cyclase --> increases cGMP --> decreases intracellular calcium causing relaxation and subseequent engorgement
Term
Phosphodiesterase 5
Definition

Degrades cGMP 

Partially accounts for detumescence (although norepinephrine released by sympathetic nerves plays a larger role)

Term
Cyclic AMP
Definition

Also involved in smooth muscle relaxation 

Agents like papaverine and PGE1 work through cAMP

Term
Cyclic nucleotide dependent kinases phosphorylate proteins which leads to
Definition

Opening of potassium channels -- hyperpolarization

Sequestration of intracellular calcium by ER

Inhibition of voltage dependent calcium channels blocking influx

Activation of myosin phosphatase 

Term
After initial diagnosis of ED...
Definition

Try lifestyle modification or termination of drugs that may cause ED

If options are unsuccessful, treatment may include drugs, psychotherapy, vacuum devices, or surgery

Term
Injectables (list) and general
Definition

Injected in base of penis (minimal pain fibers), take 5-10 min, greater rigidity of erection

 

PGE1 (alprosadil)

Trimix (phentolamine, papverine, PGE1)

Term
PGE1 (alprosadil)
Definition

Most common AE: pain at injection site

Fibrotic episodes are rare

An intraurethral form is available, however is less effective and can cause burning and itching

Term
Trimix (phentolamine, papaverine, and PGE1)
Definition

Phentolamine blocks a1 -- less constriction

papaverine causes vasorelaxation directly or indirectly inhibiting phosphodiesterase 5

PGE1 - increases cAMP

 

**pharmacologic synergy**

 

each agent is used at a lower concentration so less fibrosis 

Term
Phosphodiesterase inhibitors General
Definition

Over 50 in the body, but 5 in the penile tissues (most prominent is PDE-5 in corpus cavernosum(

Side effects from PDE-5 inhibitors are because of presence in other tissues

Term
PD-5 inhibitors MOA
Definition

Potentiates relaxant effect necessary for erection initiated by NO release from autonomic nerves of parasympathetic system and vascular endothelium 

 

Inhibition of PDE-5 prevents the degradation of cAMP - thereby potentiates relaxation of corporeal arterial and sinusoidal smooth muscle 

Term
PD5 inhibitors not recommended in
Definition
patients with recent history of stroke, MI, low BP, unstable angina, severe cardiac failure, severe liver impairment, and ESRD
Term
Sildenafil/Vardenafil bioavailability and onset of action and degradation
Definition

Oral

Onset usually an hour but some people less than 30 hour; half life is 4-6 hours;duration of effect is 4-5 hours

High fat meals decrease rate of absorption 

 

Degraded by P450 3A4 and 2C9 -- therefore patients with hepatic dysfunction, over 65 years old, or taking CYT P450 inhibitors would have elevated levels (grapefruit juice, cimetidine, erythromycin) 

Term
Efficacy of Silenafil and Vardenafil
Definition

Over 70% of patients will get an erection even with comorbidities 

Response might be lower in diabetics

 

Some patients may switch to injectables because rigidity of erection is greater; however oral form is more convenient 

Term
AE of sildenafil and vardenafil
Definition

Headache

Flushing

Dyspepsia

Nasal Congestion

Altered Vision - usually blue aura 

Diarrhea 

 

Priapism will only occur if sildenafil was used in combination with other therapies for ED 

Can potentiate effects of NO donors -- life threatening hypotension; therefore should be used in caution with people on alpha blockers 

Also in caution in patients with coronary related problems

 

Nonarteritic anterior ischemia optic neuropathy (NAION) has been thought to be associated with PDE inhibitors 

Term
Tadalafil PK and PD
Definition

Half life is 18 hours and duration of effect is 36 hours

Onset of action may be slightly longer

Plasma concentration usually unaffected by food

 

Degraded in liver by cytochrome P450 3A4 and 2C9, therefore patients with hepatic dysfunction, older than 65, or taking cytochrome p450 inhibitors could elevate drug concentration (i.e. grapefruit juice, cimetidine, erythromycin)

Term
When should sildenafil/vardenafil be taken?
Definition
1 hour before sex and not with heavy meals
Term
Efficacy of Tadalafil
Definition
Similar to the other two agents but generally al onger duration of action, 36 hours; some early studeies suggest that patients may prefer tadalafil over sildenafil
Term
Adverse effects of Tadalafil
Definition

Greatest selectivitiy of PDE5 vs PDE3A therefore less cardiac effects

Greater selectivity for PDE5 vs PDE6 therefore less visual effects 

Term
Apomorphine
Definition

Centrally acting agent

Sublingual formation that works within 20 minutes

Dopamine D1/D2 agonist

Works at level of hypothalamus

Term
Apomorphine AE
Definition
Nausea, headache, yawning, and dizziness
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