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NSAIDs I
cmbm exam IV
52
Chemistry
Graduate
01/27/2010

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Term
what cascade are NSAIDs active on?
Definition
the arachadonic acid cascade
Term
what are the 2 enzymes active in the arachadonic acid cascade?
Definition
lipoxygenases, (arachidonic acid->leukotrienes) and cyclooxygenases,(arachidonic acid->thromboxanes, prostaglandind)
Term
what is the target of NSAID inhibition? why?
Definition
cyclooxygenase, (COX). these can cut down inflammation as well as pain, (analgesic property)
Term
what things can cause pain in the body?
Definition
potassium, serotonin (anti-pain NT in CNS/pro-pain NT in PNS ), bradykinin, histamin, *prostaglandins, leukotrienes, and substance P (NT)
Term
what prostaglandins are responsible for inflammation?
Definition
PGE2 and PGI2 are responsible for erythema, edema and increased blood flow
Term
what prostaglandin is associated with the production of fever?
Definition
increased PGE2 synthesis in the hypothalamus is associated with fever
Term
how do prostaglandins affect renal function? is this good for the kidneys?
Definition
in the kidneys, prostaglandins promote increased renal flow, increased glomerular filtration rate, renal vasodilation, and increased excretion of Na+, K+ and H20 -> these are all beneficial for good kidney function
Term
how do prostaglandins affect the GI? are the effects generally positive?
Definition
prostaglandins promote secretion of mucus and inhibit the secretion of acid, (both good for the GI)
Term
how do prostaglandins affect the blood? do all prostaglandins have the same effect?
Definition
different prostaglandins have opposing effects on the blood: PGI2 inhibits aggregation, (antithrombogenic effects), and TXA2 induces platelet aggregation, (thrombogenic effects)
Term
what effect do NSAIDS have in low doses?
Definition
antithrombotic effects, through more selective inhibition of thromboxane synthesis in platelets
Term
what effect do NSAIDs have in high doses?
Definition
thrombotic effects through broad inhibition of prostacyclin
Term
what are characteristics of most NSAIDs? in terms of effects, absorption, protein binding, site of metabolism/excretion
Definition
COX inhibition, analgesic/antiinflammatory/antipyretic/antiplatelet, absorbed from stomach/small intestines, highly bound to plasma proteins, and metabolized by the liver/excreted by the kidney
Term
what are contraindications for most NSAIDs?
Definition
asa hypersensitivity, liver/renal dysfunction, alcoholism/smoking (lead to ulcers), caution during pregnancy/breast feeding (RA etc are exceptions)
Term
what are3 ex of salicylates?
Definition
salicylic acid, aspirin, diflunisal
Term
what is the generic name of aspirin?
Definition
aceytlsalicylic acid, (aspirin is an old brand name).
Term
where did salicylic acid come from originally? why did bayer acetlyate it?
Definition
a tea made from tea bark that helped with inflammation but caused GI tract pain. bayer found that acetylating salicylic acid cut down absorbtion-associated stomach pain, (hydrolysis in digestion de-acytelates it and it becomes salicylic acid again in the bloodstream)
Term
why can aspirin be considered a pro-drug?
Definition
it has to be biotransformed to be active
Term
can people w/asa allergry still have a rxn to aspercreme?
Definition
yes
Term
what are the 4 A's of aspirin action? does it affect respiration? how?
Definition
Analgesic, Antiinflammatory, Antipyretic, Antiplatelet. asa stimulates respiration by uncoupling oxidative phosphorylation and stimulating the medullary respiratory center. it also alters the acid-base equilibrium, b/c of action on heart/kidneys/respiration
Term
what is asa used for?
Definition
pain, inflammation, fever, (pyrogen-induced and CNS response), cardiac conditions to reduce blood clotting
Term
is asa's inhibition of COX reversible? what are the implications of this?
Definition
no, asa irreversibly inhibits COX. therefore effects of the drug will last until new COX is made - this is why asa is recommended after MIs
Term
does asa have high binding to plasma proteins? what does it compete with/what are the implication of that?
Definition
yes 80-90% asa competes with thyroxine, PCN, phenytoin, naproxen, sulfinpyrazone, and bilirubin, (it could displace them from that carrier protein - can be problematic w/phenytoin and thyroxine (T4 thyroid hormone), displaced over time can lead to hyperthyroidism
Term
what happens to acetylsalicylic acid in the plasma?
Definition
it is hydrolyzed to salicylate
Term
what are asa side effects on the CNS? GI? liver?
Definition
CNS: tinnitus, vertigo, confusion/delirium. GI: nausea+emesis (vomiting), local gastric irritation w/bleeding (prostaglandins increase mucus+decrease acid in the stomach/duodenum and asa decreases platelets), hepatoxicity w/prolonged high doses or viral infection
Term
what are contraindications for asa?
Definition
asa hypersensitivity, chronic liver disease, gout, peptic ulcer, hemophilia/vit K deficiency (already have excessive bleeding), diabetes (renal complications), chickenpox or influenza in children -> high risk of developing reyes syndrome, (metal retardation)
Term
what is salicylism?
Definition
asa overdose. when mild: headache/dizziness, tinnitus, dim vision, mental confusion, drowsiness, vomiting/diarrhea, sweating, thirst, nausea and hyperventilation
Term
what happens at higher dose salicylism?
Definition
generalized convulsions, skin eruptions, marked alterations in acid-base balance, fever, and serious dehydration due to hyperpyrexia, sweating, vomiting and loss of water vapor (during hyperventilation)
Term
at what plasma level are asa's analgesisic, antiplatelet and antipyretic effects seen
Definition
0-10 mg/dL
Term
at what plasma level are asa's antiinflammatory effects seen?
Definition
10-50 mg/dL
Term
at what plasma level do you start seeing asa's mild intoxication effects? **what is an important marker for this plasma level?**
Definition
50-80 mg/dL, tinnitus will start at mild intoxication
Term
at what plasma level do you start seeing asa's moderate intoxication effects?
Definition
80-100 mg/dL
Term
at what plasma level do you start seeing asa's severe intoxication effects?
Definition
110-160 mg/dL
Term
at what plasma level do you start seeing asa's lethal intoxication effects?
Definition
past 160 mg/dL
Term
what starts at mild asa intoxication?
Definition
tinnitus will start at mild intoxication, this used to be used as doctors' way of managing individual doses, (they would prescribe up to this point)
Term
what are treatments of asa toxicity?
Definition
induce emesis (vomiting), gastric lavage, activated charcoal, hydrate, and correct acid/bast balance. the first three procedures try to minimize asa levels, and the liver really has to do the rest.
Term
what is DOLOBID/diflunisal? what is its potency relative to asa? does it have anti-pyretic effects? how does it affect platelet levels?
Definition
diflunisal is a difluorophenyl derivative of salicylic acid. it is a more potent antiinflammatory/analgesic effects than asa, but has no antipyretic effects due to poor CNS penetration. it has less antiplatelet activity, leading to insignificant prologation of bleeding time and less occult blood loss than asa (blood in stool - doesn't affect platelets as much, so even if it damages the GI, clotting occurs better).
Term
what is diflunisal used for?
Definition
pain, osteoarthritis, RA -> more severe inflammatory conditions
Term
what is diflunisal's mechanism of inhibition?
Definition
it is competetive COX inhibitor
Term
how much of diflunisal binds to albumin? what does it compete with?
Definition
it binds 99% to plasma albumin and competes with oral hypoglycemics (like metformin for diabetics) and anticoagulants (coumadin/warfarin)
Term
what are side effects associated with diflunisal? is tinnitus associated with diflunisal?
Definition
dizziness, nephritis, and gastric ulceration. diflunisal does not produce tinnitus
Term
is diflunisal contraindicated for anything?
Definition
asthma, may have to do with issues of pushing respiration
Term
what is acetaminophen? what are its effects?
Definition
a para-aminophenol derivative. it is an analgesic, antipyretic, and has a weak antiinflammatory effect. it is known as paracetamol in europe.
Term
when is acetaminophen used?
Definition
when asa and other NSAIDs are contraindicated, (such as asa sensitivity or chickenpox/infuenza to avoid reyes syndrome)
Term
can acetaminophen be used to treat gout?
Definition
yes, it is used concomitantly with probenecid for gout tx
Term
what is the acetaminophen's mechanism of antipyretic action? is acetaminophen's mechanism of analgesic action known?
Definition
acetaminophen blocks COX in the hypothalamus (lowers fever) BUT elsewhere it only inhibits COX in environments w/low levels of peroxides. there are high levels of peroxides in inflammatory lesions, which is why it has weak inflammatory effects. its analgesic mechanism is unknown.
Term
how much plasma protein does acetaminophen bind?
Definition
20-50%
Term
how does the liver metabolize acetaminophen?
Definition
90%+ of acetaminophen conjugated with glucuronic acid, sulfuric acid, or cysteine in the liver. a small portion (~10%), of acetaminophen is also metabolized in the liver by microsomal enzymes
Term
can acetaminophen cause GI, bleeding, renal or pH problems? what side effects can it cause?
Definition
acetaminophen causes no GI, bleeding, renal or pH problems. it can cause hepatoxicity,
Term
what is seen within 12 hrs of acute acetaminophen intoxication?
Definition
nausea, vomiting, lethargy, renal tubular necrosis, hypoglycemic coma
Term
what is seen within 48 hrs of acute acetaminophen intoxication?
Definition
potentially fatal hepatic necrosis (dose and treatment timing dependent)
Term
what are contraindications for acetaminophen?
Definition
acetaminophen is not used for inflammatory conditions (it is however used for analgesia adjunct w/other antiinflammatory agents). it should be used with caution in light of liver disease
Term
who is the hepatoxicity and acetaminophen risk worse for?
Definition
children, (ironic b/c it used for fever reduction)
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