Intro Pharm Test #2
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- what does exercise or stress cause? (concerning norepi & epi)
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- inc norepi release from sympathetic nerve terminals --> inc in widespread sympathetic tone in target organs
- inc epi release from adrenal medulla --> inc in widespread sympathetic tone in target organs - what are the naturally occuring catecholamines?
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-epi
-norepi
-dopamine - what is a sympathomimetic?
- a drug which mimics the action of either epi or norepi (NE)
- which adrenergic receptor is selectively agonized by dobutamine (dobutrex)?
- b1
- what is/are the most important b1 site(s)?
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-heart --> inc HR & contractility
-kidney --> inc renin secretion - which adrenergic receptor is selectively agonized by albuterol, metroproterenol (alupent)?
- b2
- what is/are the most important b2 site(s)?
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-bronchial tree --> bronchodilation
-skeletal muscle --> vasodilation - which adrenergic receptor is seletively agonized by phenylephrine?
- a1
- what is/are the most important a1 site(s)?
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-skin & skeletal muscle --> vasoconstriction
-nasal mucosa --> vasoconstriction --> decongestion
-nasal glands --> dec secretions - which adrenergic receptor is selectively agonized by clonidine, methyldopa and others?
- a2
- what is/are the most important a2 site(s)?
- -vasomotor center-medulla --> dec HR & BP
- what are the classic sympathomimetic drugs?
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-epi
-NE
-isoproterenol
-dopamine
-dobutamine - what does epi do?
- inc BP by 1) positive inotropy & chronotopy which --> CO and 2) potent a1 vasopressor action in many vascular beds
- what does a positive inotropy cause?
- causes the heart to beat more forcefully
- what does NE do?
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-same effects as epi
-inc TPR --> inc systolic and diastolic BP - what does isoproterenol do?
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-same effects as epi on the heart but...
-has only b1 and b2 activity, no a activity, therefore...
-potent bronchodilator
-inc HR and contractility
-slight inc in systolic BP due to inc CO
-may be used in cardiogenic shock - what type of adrenergic activity does isoproterenol have and which does it lack?
- only has b1 and b2 activity, lacks a activity
- what does dopamine do at low doses?
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-renal vasodilation
-no change in TPR
-used to keep kidneys working in cardiogenic shock - what does dobutamine do?
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-has selective b1 action
-used in cardiogenic shock for its positive inotropy - what are other sympathomimetics that are not catecholamines, but are similar in structure?
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-phenylephrine
-ephedrine
-oxymetazoline
-amphetamine
-methamphetamine
-phenylpropanolamine
-methylphenidate
-pemoline
-amphetamine
-fen-phen - what does phenylephrine do?
- -mydriatic (a1) and decongestant (a1)
- what does ephedrine do?
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-pressor agent (a1) used:
-intra-operatively if BP is low
-in chronic orthostatic hypotension
-as a decongestant (a1)
-release of stored catecholamines
-enters the CNS --> mild amphetamine-like stimulation - what does oxymetazoline do?
- -decongestant (a1)
- what does amphetamine do?
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-release of store catecholamines
-enters CNS well --> stimulates mood and alertness, depresses apetite - what does methamphetamine do?
- -enters CNS well --> stimulates mood and alertness, inspires motorcycle gangs
- what does phenylpropanolamine do?
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-weak amphetamine variant, therefore a weak mood stimulant
-safe as an appetite suppressant, but may cause severe HTN in large doses - why were the sympathomimetics involved in the Fen-Phen diet withdrawn from the market?
- too many cases of valvulopathy and/or pulmonary hypertension.
- what does methylphenidate do?
- used for ADHD in children
- what is another name for methylphenidate?
- ritalin
- what does pemoline do?
- used for ADHD in children
- what is another name for pemoline?
- cylert
- what is adderall?
- used for adult ADHD
- what does cocaine do?
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-a local anesthetic with sympathomimetic action because it decreases NE reuptake at synapses
-enters CNS very well - what are the adverse side effects of cocaine?
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-HTN
-arrhythmias
-MI & stroke
-paranoia
-poverty
-dec fetal brain development
-other fetal abnormalities - what are the 4 sympathomimetics that make your nose feel good?
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-pseudoephedrine
-phenylephrine
-phenylpropanolamine
-oxymetazoline - what is the most common decongestant? the least common?
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-pseudoephedrine - MOST COMMON
-oxymetazoline - LEAST COMMON - what sympathomimetic is used as a therapeutic application for asthma and COPD?
- -b2 agonists
- what is the prototype sympathomimetic for asthma and COPD?
- albuterol
- what can cause "palpitations" in a patient?
- b2 agonists
- anaphylactic shock is what type of hypersensitivity reaction?
- -type I, IgE-mediated
- what does anaphylactic shock cause?
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-bronchospasm & hypersecretions --> bad dyspnea
-angioedema
-cardiovascular collapse
-can happen to anyone you give any drug or perscription to - what is the drug of choice for tx anaphylactic shock?
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-epi because it causes vasoconstriction (a1), stimulates heart (b1), bronchodilation (b2)
-also give antihistamine (benadryl inj.) and a steroid - what is the tx for HTN?
- -clonidine (catapres) & methyldopa (aldomet) are a2 agonists
- how do a2 agonists effect HTN?
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-cause 1) inc in vagal parasympathetic act to the heart --> slows it and dec it contractility & 2) a dec in sympathetic activity to the heart and peripheral vasculature --> dec HR and contractility further & dec TPR by dilating vessels
-all of which dec BP - what is given for premature labor?
- -ritodrine and terbutaline, which are b2 agonists --> relax the uterus
- what is pharmacokinetics?
- "what the body does to the drug"
- what happens after a drug is administered?
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⬢Liberation
⬢Absorption
⬢Distribution
⬢Metabolism
⬢Excretion - What Parameters Do We Use To Describe the “Fate of a Drugâ€?
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⬢Volume of distribution (VD)
⬢Clearance (Cl)
⬢Half-life (t ½)
⬢Bioavailability (F)
⬢Protein binding (PB) - what is pharmacodynamics?
- "what the drug does to the body"
- what is Volume of Distribution (Vd)?
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•The “apparent†volume in which the drug is distributed
•Actually relates the amount of drug in the body to the measured concentration in the plasma (or blood) - what is the equation for Vd?
- Vd = dose / Co
- what is clearance?
- ⬢Volume of plasma (or blood) from which drug is removed (or cleared) per unit time
- what is hepatic clearance?
- –Volume………cleared by the liver
- what is renal clearance?
- –Volume………cleared by the kidney
- t/f: clearance is usually constant
- true
- what is the equation for total clearance?
- Cl(hepatic) + Cl(renal) + Cl(lung) + Cl(other organs)
- what is half-life?
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⬢Time taken for drug concentration to decline by one-half
⬢Refers to elimination or terminal half-life - what is fractional availability?
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⬢ The fraction of unchanged drug reaching the systemic circulation following administration
⬢For IV administration, F = 1
⬢For oral administration, F is often < 1 - what is first pass effect?
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•The fraction or percentage of an orally administered drug removed on the first pass through the gastrointestinal wall and/or liver before reaching the systemic circulation
•Conventionally
–First Pass = 1 – fractional bioavailability - what is an example of alternations in absorption?
- chelation
- what is chelation?
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⬢Irreversible binding of drugs in the GI tract
⬢Tetracyclines, quinolone antibiotics - ferrous sulfate (Fe+2), antacids (Al+3, Ca+2, Mg+2), dairy products (Ca+2)
⬢Usually separating administration of chelating drugs by 2+ hours decreases interaction effect
⬢Dose tetracycline 1 hour before or 2 hours after dairy products - what is Interindividual Variability?
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Pharmacogenetics
⬢There are wide interindividual differences in drug metabolizing ability which may arise from genetically determined differences in the basal level of expression of an enzyme
⬢Poor metabolizers will have high plasma concentrations of parent compounds and low concentration of metabolites - what are the most common single agent drug interactions?
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⬢Cimetidine
⬢Digoxin
⬢Antacids
⬢Warfarin
⬢Propranolol
⬢Theophylline - what are the Dose-Effect Parameters?
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POTENCY: The sensitivity of an organ or tissue to the drug
EFFICACY: The maximum effect - what is the dose response curve?
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-relates the amount administered to the response
-response may be measured as % responding or as intensity of response.
-it's sigmoidal in shape