Exam 1 Flashcards
what about the structure of LAs increases their lipophilicity?
longer hydrocarbon chain and interconnecting chain
how do ester and amide LA metabolism differ?
esters - metabolized by plasma and liver pseudocholinesterases
amides - metabolized by liver P450s
how does LA change on either side of the cell membrane?
outside - uncharged
inside - becomes charged (this is what blocks the channel)
which drugs are used for topical anesthesia
benzocaine and cocaine
procaine and lidocaine can both be used for which 3 forms of LA?
infiltration (injection), epidural, spinal
why does LA getting to the brain cause convulsions?
d/t blockade of the GABA-A receptors (causes decr inhibition)
how is cocaine the exception when it comes to LAs having adverse cardio effects?
causes tachycardia, vasoconstriction, HTN
how does Epi affect the action of LAs?
it incr the LA action by 50%
how does diazepam aid in the tox caused by LAs?
treats convulsions d/t systemic absorption by activating the GABA-A receptors in the CNS
how is clonidine used as an adjunct in LA admin?
decr substance P and glutamate release (decr pain transmission)
which routes of LA admin is clonidine used in?
epidural and spinal
what are the protective components of the stomach?
mucous, bicarbonate, PGE
why do you need to be careful with cimetidine?
it is metabolized by CYPs so can interact with warfarin and phenytoin
which patients need a dose adjustment for H2 blockers?
renal insufficiency
how long does one dose of omeprazole work for?
t1/2 = 1.5hrs, however decr acid secretion for 2-3 days
rare side effects of omeprazole
nausea, diarrhea, dizziness
how do PPIs affect the bones with longterm use?
decr acidity decr the amount of Ca absorbed so bones more fragile
what is the first choice treatment in Zollinger-Ellison syndrome?
omeprazole
what indication is omeprazole less than ideal for?
occasional heartburn
which upper GI drugs can you develop a tolerance to?
H2 blockers
when can antacids be taken?
after a meal when there is acid present
what AE does Mg(OH)2 have if given alone?
diarrhea
what AE does Al(OH)3 or CaCO3 have if either are given alone?
constipation
how can antacids affect the urine?
they can increase the pH and alter the elimination of acidic and basic drugs
which drugs do Al(OH)3 and CaCO3 alter the absorption of?
tetracycline, INH, ketoconazole
which drug must be admin 2 hours after tetracycline, phenytoin, and digoxin and why?
sucralfate b/c it can absorb other drugs
when must sucralfate be admin?
before a meal
what strange AE does bismuth cause?
blackened tongue and stool
why can’t bismuth be used in children?
salicylate acid causes Reye’s syndrome
what is bismuth esp good for and why?
H. pylori infection d/t antimicrobial feature
what is misoprostol CI in?
pregnancy (d/t induction of contractions)
which drugs is B12 malabsorption associated with? why?
PPIs
d/t the fact that B12 absorption needs an acidic environment
where is the majority of 5-HT produced?
guts
how does metoclopramide affect the LES and pyloric sphincters?
incr LES tone to prevent backup
relaxes pyloric sphincter tone to incr gastric emptying
how do the MOAs for metoclopramide and ondansetron differ?
metoclopramide - D2 & 5-HT3 antagonist; 5-HT4 agonist
ondansetron - 5-HT3 receptor antagonist
how can ondansetron effectiveness be incr?
adding dexamethasone or aprepitant
metoclopramide AEs
parkinsonism like sx, tardive dyskinesia
ondansetron AEs
constipation and headache/GI sx
why can’t linaclotide be used in children
reports of mortality d/t dehydration in mice
how do linaclotide and lubiprostone MOAs differ?
Linaclotide - activates CFTR via cGMP
Lubiprostone - directly activates ClC2 Cl channel
what type of solution is Mg(OH)2 as an osmotic laxative and how does this affect its MOA?
admin as hypertonic solution which incr osmotic pressure and causes accumulation of fluids in GI tract
what are the indications for saline laxative (MgOH2)?
colonoscopy prep
IBS-C
how do steroids help IBD?
reduce ulceration and cause initial remission
what are the GI prodrugs?
omeprazole, sulfasalazine, azathioprine
adverse effects of 5-ASA
diarrhea, nausea, headaches, hypersensitivity, bone marrow suppression
AE of infliximab
infections (d/t immunosuppression)
what is azathioprine good for?
IBD long term treatment (response could take weeks-months)
which drugs are substrates for P450 enzymes and therefore can have their metabolism affected by ethanol
TCAs, H1 antihistamines, narcotics, anticonvulsants, BZs
lethal dose of alcohol
> 500mg/dL
at what dose of alcohol does impaired driving occur?
50-80 mg/dL
alcohol’s affect on GABA
at high conc, it will incr the inhibitory effect of GABA
what is the mechanism behind alcohol induced vomiting
alcohol excites the 5-HT3 receptors which leads to emesis
why can’t acetaminophen be used with alcohol?
it coverts acetaminophen to a hepatotoxic metabolite
what are the 3 endocrine effects of alcohol use?
gynecomastia, testicular atrophy, salt retention
tx for alcohol w/d syndrome
long acting BZs (diazepam, chlordiazepoxide), clonidine, propranolol
what does chronic EtOH use incr (neurologically)
incr synaptic concentration of dopamine, serotonin, endogenous opioids
how do functional tolerance and metabolic tolerance differ?
metabolic tolerance - d/t induction of MEOS enzymes
functional tolerance - reduction of CNS sensitivity to alcohol d/t down regulation of GABA receptors, up regulation of NMDA (glutamate) receptors, up regulation of Ca channels
how is naltrexone used for alcoholism?
anti-craving b/c it reduces the reward assoc w/alcohol consumption
which population do you need to be careful with in prescribing naltrexone? why?
opioid dependent patients b/c it can lead to severe w/d
other than naltrexone, which medications are used for used for their anti-craving effect?
acamprosate and topiramate
what is NAC?
N-acetylcysteine
used to tx chronic alcoholics suspected of acetaminophen poisoning which could lead to irreversible liver damage
what is fomepizole used for?
antidote to methanol and ethylene glycol toxicity
how does one get ethylene glycol poisoning?
industrial exposure or drinking antifreeze
what is oxalic acid?
what ethylene glycol is metabolized to
can cause severe acidosis and renal damage
what is used to prevent the results of ethylene glycol toxicity?
ethanol (will compete for oxidation by ADH)
what is the Narcan test
used if you suspect recovering alcoholic is abusing opioids
what is methanol metabolized into and what can it cause?
formaldehyde which can cause severe acidosis, blindness, and retinal damage
how can methanol intoxication be reversed?
IV ethanol (will compete for ADH and prevent the oxidation of methanol)
how do clonidine and propranolol each decr sympathetic outflow?
clonidine - activates alpha2 adrenergic receptors in the CNS
propranolol - block beta adrenergic receptors in the CNS
more lipid soluble an anesthetic the more ______ it is
potent
how is anesthetic uptake calculated
gas solubility in the blood x cardiac output x gradient between alveolar and blood anesthetic partial pressures
why is it beneficial that inhaled anesthetics decr CO?
higher CO means slower induction b/c it removes the agent faster from the alveoli and thus takes longer for equilibrium to be reached between the alveoli and the brain (lower CO means less anesthetic taken to the periphery which is not the site of action)
what is MAC?
minimum alveolar concentration - end tidal concentration of inhaled anesthetic needed to eliminate movement in 50% of patients stimulated by an incision
what are BZs good for?
reduce anxiety, induce amnesia
what are antihistamines good for?
ppx for allergic rxn, some sedation
what are antiemetics good for?
prevent aspiration, decr postop N/V
what are opioids good for?
provide analgesia
what are antimuscarinics good for?
amnesia, prevent bradycardia and fluid secretion
what are muscle relaxants good for?
facilitating intubation
what is the big disadvantage with halothane?
halothane hepatitis
what is the MC used inhaled anesthetic?
isoflurane
what are the advantages with isoflurane?
CO maintained, systemic vessels dilate causing small decr in BP, arrhythmias are uncommon, potent coronary vasodilator
why are sevoflurane & desflurane unique?
can be used for outpatient anesthesia d/t rapid recovery
NO provides ____ but not ____
analgesia; anesthesia
what are the characteristics of malignant hyperthermia?
sustained muscle contraction, lactate production, increased body temp
how does dantrolene tx malignant hyperthermia?
reduces intracellular Ca
what should be provided upon d/c of NO and why?
100% oxygen b/c hypoxia may occur
why should NO be used w/caution in closed spaces?
it incr the volume of closed spaces (can cause pneumothorax or incr pressure in sinus)
what is the milk of amnesia?
propofol (hypnotic and forgetful rest)
what determines the duration of action for IV anesthetics?
redistribution to body groups (VRG, muscle groups, fat group, vessel poor group)
what is the advantage of sodium thiopental?
little postop excitement or vomiting
which patient population is ketamine better for and why?
kids
adverse effects less common
what are the AEs of ketamine?
incr muscle tone causing involuntary movements
hallucinations
what is the unique advantage of ketamine?
does not cause respiratory depression
may cause incr in BP
what is the unique advantage of etomidate?
antagonist available
if a drug accumulates somewhere what does that mean in terms of recovery?
it will be slow
which IV agent(s) provide analgesia?
ketamine
which IV agents do not provide analgesia?
propofol, sodium thiopental, etomidate
which IV agent can cause a painful injection?
etomidate
what type of proteins do DAAs target?
non-structural proteins
what is the BBW for DAAs?
HBV reactivation of HCV/HBV coinfection
what are the 3 types of DAAs?
protease inhibitors (PIs, NS3/4), polymerase inhibitors (NS5B), NS5A inhibitors
How does clonidine effect the C and A fibers?
Activates a2 adrenergic receptors on both fiber types to decr release of glutamate and substance P
How is clonidine used in LA admin?
Adjunct to epidural and spinal
What is the diazepam mechanism of action?
Activate GABA in CNS
For which drug does the isomer used matter? And why?
Ropivacaine - S isomer has low affinity for cardiac Na channels
What are the antimuscarinics? And what do they do?
Scopolamine and atropine
Cause amnesia and prevent bradycardia and fluid secretion
Blood:gas coefficient tells us what about the GA?
Onset
MAC tells us what about the GA?
Potency
