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29 Cards in this Set
- Front
- Back
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what does detumescence mean?
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is being flaccid; the oppiste is tumescence: state of being swollen or engorged
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what tissues of the penis are involved in erection?
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corpora cavernosa
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what are the types of erectile dysfunction?
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psychogenic, organic, or mixed
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explain the main mechanism of an erection.
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vasodilation occurs and blood flows into the cavernosal arteries in the corpora cavernosa, blood fills both columns of erectile tissue; this swelling causes the veins to be compressed and blood is not allowed out of the penis
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explain the molecular mechanism of an erection.
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nitric oxide activates guanylate cyclase; guanylate cyclase is needed to convert GTP to cGMP; cGMP causes smooth muscle relaxation and thus tumescence (aka erection)
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what causes detumescence?
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PDE5 (phosphodiesterases) degrade cGMP; thus treatments for erectile dysfunction (ie. maintainence of an erection) include inhibiting PDE5
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what neurotransmitters are involved in penile smooth muscle relaxation?
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ACh, NO, Vasoactive Intestinal polypeptide (VIP), prostaglandin E1, calcitonin gene-related peptide
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what neurotransmitters are invovled in penile smooth muscle contraction?
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NorE, Endothelin 1, neuropeptide Y, and ATP
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list the potential risk factors for ED?
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Diabetes, Smoking, aging, hypertension, hyperlipidemia, vascular disease, depression, and variety of drugs
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clonidine, methyldopa, hydrochlorothiazide, beta andrenocetpor antagonist are what type of drugs and can cause what?
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antihypertensives; ED
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MAOI, TCAs, phenothiazines, and benzodiazepines are what can of drugs and can cause what?
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psychotropics; ED
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sedatives, narcotics, ethanol, and anxiolytics are what type of drugs and can cause what?
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CNS depressants; ED
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These are other miscellaneous treatments that may cause ER.
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atropinics, estrogens, cimetidine, anticancer drugs
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in the past this injectable was used and worked by directly relaxing the cavernosal smooth muscles due to the action of intracellular Ca levels.
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papaverine (direct intracavernosal injection)
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this injectable is an irreversible alpha receptor antagonist (this it keeps it from constricting)
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phenoxybenzamine
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why are the injectables less commonly used today?
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high incidence of penile fibrosis and penile fibrotic nodules
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what injectable is used more commonly today?
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PGE1 (alprostadil); have to give it locally b/c it gets broken down too fast orally and is poorly absorbed
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what are PGE1's main MOA?
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calcium mobilization and prejunctional action affecting neurotransmitter release
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besides the injectable, how else is alprostadil used?
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intra-urethral delivery...whew.(high incidence of burning and itching)
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what oral drugs utilize the PDEV inhibitor method and work by increasing the amount of cGMP?
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sildenafil (Viagra); vardenafil (Levitra); and tadalafil (Cialis) - "-fil the penis"
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Name the time to peak, half-life, and whether there are food interactions to sildenafil?
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peak=60min; T1/2=3-4hrs; interaction with food= yes
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Name the time to peak, half-life, and whether there are food interactions to vardenafil?
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peak=50min; T1/2=4-5hrs; interaction with food= yes
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Name the time to peak, half-life, and whether there are food interactions to tadalafil?
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peak=120min; T1/2=18hrs; interaction with food=no
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by what enzyme are the PDE5 drugs metabolized?
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P450 3A4
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name some inhibitors of CYP3A4?***(bolded)
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cimetidine, ketoconazole, erythromycin (thus, these will decrease the clearance and keep the drug in the system longer)
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name the side-effects of PDE5.
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headache, flushing, dyspepsia, nasal congestion, priaprism (with sildenafil may get blue/green hue since it inihibts PDE6 too which is round in the retina) TADALAFIL*** does not disrupt PDE-6
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what is absoultely contra-indicated when taking a PDE5 inhibitor and why***?
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any drug containing nitrates; nitroglycerin, isosorbide methylnitrate;amyl nitrate (used illicity) should never be combined either; May cause life-threatening HYPOTENSION
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name a possible drug interaction with PDE5 inhibitors?
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anything that lowers BP, especially alpha adrenergic antagonists (used with BPH) exception: tamsulosin (Flomax) may be used safely with tadalafil***
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what sublingual dopamine agonist is being used in europe to treat ED.
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apomorphine - a CNS drug
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