Pharmacology Flashcards
What are the phase I reactions in hepatic metabolism?
oxidation reduction hydrolysis
What are the phase II reactions in hepatic metabolism?
glutathione conjugation sulfation acetylation glucuronidation
How does blood flow affect extraction ratio?
For drugs with high intrinsic clearance, extraction ratio is nearly independent of blood flow. For drugs with low intrinsic clearance, extraction ration is inversely proportional to blood flow.
Should drugs with a high or low extraction ratio be adjusted for low liver blood flow states?
high extraction ratio
Should drugs with a high or low extraction ratio be adjusted for liver failure?
low extraction ratio
What is context dependent half-life?
The longer you infuse a drug, its half-life steadily rises to approach the elimination half-life.
Name some drugs that show tachyphylaxis.
ephedrine nitroglycerine opioids local anesthetics dobutamine hydralazine
What drugs most commonly cause anaphylactic reactions?
muscle relaxants latex barbiturates antibiotics local anesthetics (esters >> amides)
What patient factors increase MAC?
hyperthermia chronic etOH use increased catechol levels daytime cocaine use
What patient factors decrease MAC?
hypothermia pregnancy hypotension hypoxemia acute etOH use nighttime
What is the Meyer-Overton correlation?
linearly decreasing potency of anesthetic agents with increasing lipophilicity
Which anesthetic agents have the fastest rate of rise of FA/FI (fastest to slowest)?
nitrous oxide desflurane sevoflurane isoflurane
What is the effect of a R to L shunt on speed on inhaled induction?
slows induction
What is the effect of a L to R shunt on speed on inhaled induction?
no effect on its own but can attenuate the slowing of induction caused by a co-existing R to L shunt
What is the concentration effect?
Nitrous oxide is taken up so quickly into the blood stream that a void is created in the alveolus that draws in more fresh gas and increases the rate of rise of FA/FI.
What is the second gas effect?
When another anesthetic gas is used in the presence of nitrous oxide, the rate of rise of its FA/FI is faster as rapid uptake of nitrous oxide concentrates the remaining gases in the alveolus.
Which inhaled anesthetic best preserves SVR?
halothane
What are the predominant respiratory effects of inhaled anesthetics?
decreased tidal volume and increased respiratory rate decreased PaCO2 responsiveness increased dead space decreased FRC
What is the effect of inhaled anesthetics on NMBs?
potentiate the activity of both classes of NMBs
What is the effect of nitrous oxide on the pulmonary vasculature?
increase PVR
What kind of hepatic toxicity is caused by inhaled anesthetics?
immune-mediated centriobular necrosis
Which inhaled anesthetic agents release the most fluoride ion?
methoxyflurane >> enflurane > sevoflurane > isoflurane = desflurane = halothane
What problem can arise from dried CO2 adsorbent? (“First case Monday morning effect”)
carbon monoxide production
What is the recommended exposure limit for inhaled anesthetics?
25 ppm per hour for nitrous oxide 2 ppm per hour for all others
What are the cardiovascular side effects of barbiturates?
decreased CO and MAP venous pooling decreased sympathetic output
Which IV anesthetics should not be used in patients with porphyria?
methohexital thiopental
What are the undesirable side effects of etomidate?
adrenal suppression (11-beta hydroxylase inhibition) nausea/vomiting thrombophlebitis/pain at injection site
What are the cardiovascular effects of ketamine?
releases endogenous catecholamines to increase CO, HR, SVR direct cardiac depressant if endogenous catecholamines are depleted
What are the respiratory effects of ketamine?
bronchodilator - good for refractory asthma
What is propofol infusion syndrome?
associated with 4 mg/kg/h infusion for >48 h refractory bradycardia, metabolic acidosis, rhabdomyollysis, and fatty liver
What happens to CO2 responsiveness with Precedex?
preserved
What are the cardiovsacular effects of Precedex?
initial HTN with bolus then reduced HR, SVR, and CO
What are the side effects of scopolamine?
Blurred vision, dizziness, dried mouth, agitation
Which serum proteins bind most drugs?
albumin binds acidic drugs alpha-1 glycoprotein binds basic drugs
Which opioid effects are associated with Mu1 receptors?
euphoria and urinary retention
Which opioid effects are associated with Mu2 receptors?
hypoventilation, constipation, physical dependence
Which opioid receptors are associated with dysphoria?
delta and sigma
Which opioids cause significant histamine release?
morphine and meperidine - can cause bronchospasm
Which opioid can cause tachycardia?
meperidine - similar structure to atropine
Which opioid effects do not show tolerance?
miosis and constipation
What is the target of neuraxial opioids?
mu receptors in the substantia gelatinosa that inhibit the release of substance P
How is remifentanil metabolized?
plasma esterases
Which opioid is also an NMDA antagonist?
methadone
Which drugs can prolong the action of non-depolarizing NMBs?
Ca channel blockers local anesthetics volatile anesthetics ketamine aminoglycosides lithium
Which electolyte abnormalities can prolong the action of non-depolarizing NMBs?
hypernatremia hypokalemia hypocalcemia
Metabolism of which NMBs produces laudanosine and lowers seizure threshold?
atracurim and cis-atracurium
What is the dibucaine number of normal pseudocholinesterase? Atypical pseudocholinesterase?
Normal: 80 Atypical: 20
What conditions decrease plasma esterase concentration and prolong succinylcholine’s effects?
Drugs (metoclopramide, esmolol, OCPs) liver failure pregnancy hypothermia
Why does diazepam have such a long duration of action despite its quick onset?
Diazepam has two active metabolites, oxazepam and desmethyldiazepam, that extend its duration of action
Which benzodiazepine does not have active metabolites?
Lorazepam
Which drugs may prolong the sedative effects of midazolam?
Erythromycin, calcium channel blockers, protease inhibitors, and grapefruit juice
Which food allergies are associated with latex allergy?
Avocado, banana, mango, kiwi, passion fruit, chestnut
What is the timing of allergic reactions to latex?
More than 30 min after exposure
What is ritodrine and how is it commonly used?
a selective beta-2 agonist as a tocolytic
What is the dosing of 20% intralipid?
Bolus 1.5 mg/kg Infuse 0.25 mL/kg/min
