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55 Cards in this Set
- Front
- Back
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What is the result of sympathetic stimulation?
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increased rate and force of heart contractions
rise in blood pressure shift of blood flow to skeletal muscles dilation of bronchioles and pupils increase in blood glucose leves |
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What chemical class of substances are epinephrine and norepinephrine?
What configuration is the natural enantiomer? |
catecholamines
R |
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List the enzymes needed for epinephrine synthesis and the location it occurs
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Tyrosine hydroxylase
L-aromatic amino acid decarboxylase Dopamine B-Hydroxylase (inside storage vesicals) Phenylethylamine N-metheyltransferase (inside adrenal gland) |
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What ion does tyrosine hydroxlase use and what does it require as a cofactor?
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Fe2+
tetrahydrobiopterin |
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What is tyrosine hydroxylase inhibited and activated by?
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inhibited by NE
activated by cAMP |
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What is the rate determining step for epinephrine synthesis?
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tyrosine hydroxylase
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what does L-aromatic aa decarboxylase use as a cofactor?
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pyridoxal phosphate
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What element does dopamine B-hydroxlase use?
What is its cofactor? |
Cu2+
ascorbic acid |
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What occurs if there is a tyramine build up?
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hypertensive crisis
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What kind of receptor are adrenergic receptors?
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G-coupled receptors
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What classes of adrenergic receptors are there?
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alpha and beta
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what is the agonist potency on alpha and beta 1 2 and 3 receptors concerning epinephrine, norepinephrine and isoproterenol?
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a1, a2 - Epi > NE >> ISO
B1 - ISO > EPI = NE B2 - ISO > EPI >> NE B3 - ISO = NE > NE |
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Which receptor is presynaptic?
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a2
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What receptors go with the organs and what is the response when stimulated?
arterioles heart lungs liver fat cells intestine kidney uterus veins |
Arterioles
a1 - constriction b2 - dilation heart b1 - increased rate and force of contraction Lungs b2 - relatation (bronchial dilation) Liver a and b - increased glycogenolysis fat cells a and b - lipolysis intestine a and b - decreased motility kidney b1 - renin secretion uterus a1 - contraction b2 - relaxation veins a - constriction |
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What is Metyrosine?
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a competiative inhibitor of tyrosine hydroxylase (catecholamine biosynthesis inhibitor)
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What is Metyrosine used for?
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preoperative management of pheochromocytoma (benign tumor in adrenal medulla causing excessive release of catecholamines) which can lead to hypertensive episodes
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What isomer of Metyrosine is bioactive?
what is the dose what is a main side effect? |
the (-)-isomer is bioactive
dose - 0.6g/day side effect crystalluria |
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What should you not use with metyrosine?
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sulfa drugs
alkalinize urine if need to use |
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What is Reserpines MOA?
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vesical storage inhibitor
prevents storage of NE in sympathetic neurons and of epinephrine in adrenal medulla it binds strongly to monoamine transporter |
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What is the pharmacokinetics of reserpine and its indications?
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slow onset, long duration
indicated for treatment of hypertension and psycotic disorders such as schizophrenia |
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What is guanethidine and guanadrel? and its MOA?
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neuronal blocking agents
prevents release of NE from sympathetic nerve terminals to the synaptic cleft it accumulates within the neuronal storage vesicals and prevents fusion of the vesical with the neuronal membrane |
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what is guanethidine and guanadrel used for?
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treating hypertension
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WHat is NE used for?
what is addd to the preperation and used as an antioxidant? |
to maintain blood pressure in acute hypotensive states
sodium bisulfite |
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What is epinephrine used for?
side effects? |
potent stimulator of a and b adrenoreceptors
used in anaphylactic rxns cerebral hemorrhage and cardiac arrhythmias |
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what is dopamine used for?
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treatment of severe congestive heartfailure
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What is the main point of the easson-stedman hypothesis?
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a drug must bind to a minimum of three spots on a receptor
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what does direct acting mean?
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interacts directly with adrenergic receptors elicting sympathomimetic resonse
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indirect acting?
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causes release of norepinephrine from adrenergic nerve terminals
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mixed mechanism?
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combo of indirect and direct acting
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what are phenylephrine and methoxamine and what are they used for?
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a1 agonists
phenylephrine is a potent vasoconstrictor (direct acting) used in severe hypotension, nasal congestion, and open angle glaucoma methoxamine is a potent vasoconstrictor (direct acting) - used to treat hypotension caused by surgery or shock |
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What is the difference between metaraminol and midodrine?
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midodrine is a orally active prodrug of metaraminol
both are a1 selctive |
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Xylometazoline, Oxymetazoline, Naphazoline, and tetrahydrozoline all contain what?
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an imidazoline ring
a1 agonists topical nasal decongestants and in eye drops |
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bulky groups and the meta or para possitions offer greater affinity for a1? T/F
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TRUE
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Name 5 a2 selective agonists
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clonidine, aproclonidine, brimodine, guanfacine, guanabenz
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What is clonidine used for along with side effects?
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antihypertensive
side effects - sedation, dry mouth, sudden discontinuation causes withdrawl symptoms contains guanidine structural fragment |
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what is aproclonidine and brimonidine used for?
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topical treatment of glaucoma
decreased production of aqueous humor and increased outflow reduces intraocular pressure |
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What are better a2 agonists then clonidine?
when are they used? |
guanfacin and guanabenz
preferred drug during pregnancy |
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what is isoproterenol?
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b adrenergic agonists
causes brochodilation nonselctive |
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how are b2 selective adreneric agonists metaproterenol and terbutaline metabolized?
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through glucuronidation
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what effect does inhalation have on b selectivity?
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greater b2 selectivity
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what is bitolterol a prodrug of?
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colterol
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what is ritodrine used for?
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b2 selective agonist
utrine relaxation |
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what type of agonists are amphetamines?
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indirect agonists
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what do a antagonists lead to?
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decrease in blood pressure
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what do B-haloalkylamines do?
what are they indicated for? |
block a1 and a2 receptors irreversibly
inhibits uptake of catecholamines into adrenergic nerve terminals indicated for pheochromocytoma preoperatively and chronic major side effect is postural hypotension |
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what are b-haloalkalamines related to?
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nitrogen mustards
forms aziridinium ion intermediate |
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what is tolazoline and what is it used for?
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non-selective a antagonist used for persistent pulmonary hypertension of newborns
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what is phentolamine and what is it used for?
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nonselective a antagonist used to control hypertension in pts with phenochromocytoma
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name three a1 antagonists
inidcation |
prazosin, terazosin and doxazosin
systemic hypertension |
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name the nonselective b blockers (5)
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propranolol, naphthoxylactic acid, timolol, penbutolol, pinmdolol
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what are beta blockers indicated for?
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hypertension, ischemic heart disease, CHF, arrhythmias
lowers heart workload by slowing down theheart rate and decreasing force of contraction |
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name b1 selective antagonists
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metoprolol, atenolol, esmolol, beaxolol, acebutolol, diacetolol
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why should b blockers be used in caution in pts with asthma?
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because it has the potential to cause bronchoconstriction
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why do b blockers need to be used with caution in diabetics?
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can cause frequent hypoglycemic rxns due to inibition of catecholamine induced glycogenolysis
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what is significant about esmolols duratin of action?
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it is very short (8-9 min half life) but has a rapid on set of action (10-20 mins).
its usful in surgury or emergency situatinos for short term control of heart rates |
