Pharmacology Flashcards

1
Q

Why are obese patients relatively resistant to succinylcholine?

A

increased butyrylcholinesterase (pseudocholinesterase) levels

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2
Q

Accumulation of which narcotic metabolites is of concern in patients with renal failure?

A
  • hydromorphone-3-glucuronide -> neuro-excitation and cognitive impairment
  • morphine-6-glucuronide -> active metabolite
  • normeperidine -> seizures
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3
Q

Which drugs are metabolized by butyrylcholinesterase (pseudocholinesterase)?

A

succinylcholine

mivacurium

physostigmine

organophosphates

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4
Q

Which drugs are metabolized by plasma esterases?

A

remifentanil

esmolol

ester local anesthetics

succinylcholine

atracurium (also Hoffman elimination)

etomidate (also liver metabolism)

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5
Q

How is lorazepam metabolized?

A

glucuronidation in the liver (also oxazepam and temazepam)

* no active metabolites *

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6
Q

What factors influence myalgias following succinylcholinc administration?

A

more common in women

more common with minor surgery

more common with early ambulation

less common in pregnant vs. non-pregnant women

less common in children and elderly patients

less common with greater muscle tone

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7
Q

What metabolic functions are served by the lung?

A
  • conversion of angiotensin I to angiotensin II
  • inactivation of bradykinin (by ACE)
  • inactivation/uptake of norepinephrine; serotonin; and prostaglandins E1, E2, and F2alpha
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8
Q

How long is a time constant?

A

The time it would take an exponential process to be complete if the initial rate had continued.

1 time constant: 63% complete

2 time contants: 87.5% complete

3 time constants: 95% complete

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9
Q

What is ED95 in the context of muscle relaxants?

A

dose needed to decrease twitch height by 95%

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10
Q

What drugs exhibit zero-order kinetics?

A

ethanol

thiopental

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11
Q

How does renal failure affect volume of distribution? How does this affect drug dosing?

A
  • increases volume of distribution due to decreased plasma binding proteins
  • should increase loading dose and dosing interval
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12
Q

How are midazolam and diazepam metabolized?

A

cytochrome P450 oxidation in the liver

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13
Q

Besides IV administration, which route provides highest plasma levels of midazolam?

A

intramuscular

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14
Q

Where are opioid receptors predominantly located?

A
  • periaqueductal gray (brainstem)
  • amygdala
  • corpus striatum
  • hypothalamus
  • substantia gelatinosa
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15
Q

Which serum proteins bind most drugs?

A

albumin binds acidic drugs

alpha-1 glycoprotein binds basic drugs

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16
Q

Which opioid side effects are associated with Mu 1 receptors? Mu 2 receptors? Kappa receptors? Delta and sigma receptors?

A

Mu 1: urinary retention and euphoria

Mu 2: constipation, physical dependence, and hypoventilation

Kappa: dysphoria and hallucinations

Delta and sigma: dysphoria

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17
Q

Which opioids cause significant histamine release?

A

morphine and meperidine - can cause bronchospasm

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18
Q

Which opioid can cause tachycardia?

A

meperidine - similar structure to atropine

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19
Q

Which opioid effects do not show tolerance?

A

miosis and constipation

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20
Q

How is remifentanil metabolism different between adults and infants?

A

faster in infants

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21
Q

What are the equivalent IV and PO doses of morphine? Hydromorphone?

A

morphine: 10 mg IV = 30 mg oral
hydromorphone: 1 mg IV = 5 mg oral

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22
Q

Which narcotic has local anesthetic activity?

A

meperidine

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23
Q

Which narcotic effects are reversed by naloxone? Which are not?

A

Reversed: respiratory depression, analgesia, pruritis

Not reversed: constipation, nausea/vomitting, muscle rigidity

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24
Q

What is the primary organ for redistribution of propofol when it residtributes from the brain?

A

skeletal muscle

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25
Q

What are the features of propofol infusion syndrome?

A

metabolic acidosis

rhabdomyolysis

hyperkalemia

bradycardia

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26
Q

What are some common indications for ketamine?

A

cardiac tamponade (increased HR and SVR)

bronchial asthma (bronchodilatory)

tetralogy of Fallot

hypothyroidism

27
Q

What drugs are contraindicated in acute intermittent porphyria?

A

barbiturates

etomidate

hydralazine

steroids

OCPs

alpha-methyldopa

chlordiazepoxide

nitrazepam

flunitazepam

28
Q

How much will nitrous oxide expand a pneumothorax?

A

50% N2O: 2x

66% N2O: 3x

75% N2O: 4x

29
Q

How much of each inhaled anesthetic is metabolized by the body rather than exhaled?

A

halothane: 20%

sevoflurane/enflurane: 2%

isoflurane: 0.2%
desflurane: 0.02%

30
Q

What are the OSHA guideline for exposure limits to inhaled anesthetics?

A

N2O: 25 ppm/hour

all others: 2 ppm/hour

31
Q

What is the Overton-Mayer theory?

A

correlation between lipid solubility of anesthetic agents and their potency

32
Q

What factors increase MAC?

A

neonates

chronic alcoholism

acute amphetamine use

MAOIs, cocaine

hyperthermia

hypernatremia

33
Q

What factors do NOT affect MAC?

A

duration of anesthesia

gender

pH or PaCO2

hypo/hyperthyroidism

34
Q

What factors decrease MAC?

A

old age

pregnancy

hyperbaric chamber (nitrogen narcosis)

chronic amphetamine use

acute alcohol use

35
Q

What factors increase carbon monoxide production in the anesthesia circuit?

A

desflurane

low gas flows

dry or warm absorbent

baralyme > sodalyme

36
Q

What is the order of onset and recovery of neuromuscular blockade in different muscle groups?

A

diaphragm > laryngeal muscles > adductor pollicis

37
Q

How do antibiotics affect neuromuscular blockade?

A

All antibiotics potentiate blockade, EXCEPT:

penicillin

cepharlosporins

erythromycin

38
Q

What is the best clinical test of adequate neuromuscular blockade?

A

neonates: sustained leg lift
adults: masseter muscle tone

39
Q

How is the dosing of rocuronium and neostigmine affected by renal failure?

A

clearance of both is prolonged, dose should be reduced

40
Q

What is the significance of dibucaine number?

A

butyrlcholinesterase alleles:

80: WT

40-60: heterozygous

20: mutant

41
Q

How much does succinylcholine increase postassium levels in a normal patient?

A

0.5 mEq/L

42
Q

Which electrolyte abnormalities prolong neuromuscular blockade?

A

“Louis CK”

hypocalcemia

hypokalemia

“Hymen”

hypermagnesemia

hypernatremia

43
Q

Which drugs prolong the duration of action of both depolarizing and non-depolarizing muscle relaxants?

A

lithium

magnesium

44
Q

Which drugs inhibit butyrlcholinesterase and prolong the duration of action of succinylcholine?

A

metoclopramide

pancuronium and mivacurium

acetylcholinesterase inhibitors

nitrogen mustard, trimataphan, and echothiophate

45
Q

How do ester local anesthetics interact with acetylcholinesterase inhibitors (neostigmine, pyridostigmine)?

A

ester local anesthetics potentiate acetylcholinesterase inhibitors

46
Q

What properties affect onset time of local anesthetics?

A

pKa (lower is faster)

concentration

47
Q

Which properties affect the duration of action of local anesthetics?

A

protein binding (stronger is longer)

48
Q

Which properties affect the potency of local anesthetics?

A

lipid solubility

49
Q

Which local anesthetics can cause methemoglobinemia?

A

benzocaine and prilocaine

50
Q

Which drugs are contraindicated in G6PD deficiency?

A

nitrofurantoin and sulfa

isoniazid and dapsone

methylene blue

anti-malarials

51
Q

Are patients with G6PD deficiency more or less susceptible to methemoglobinemia?

A

more susceptible

52
Q

What are the properties of tumescent lidocaine used for liposuction?

A

concentration: 0.025-0.1%
dose: 35-55 mg/kg

time to peak concentration: 12-14 h

epinephrine: 1:1,000,000

53
Q

What are the target receptors of metoclopramide?

A

D2 antagonist

5HT3 antagonist

5HT4 agonist

54
Q

What are the clinically used ß2 agonists?

A

albuterol

terbutaline

ritodrine

55
Q

What are the common side effects of ß2 agonists?

A

hypotension

tachycardia

hyperglycemia

pulmonary edema

hypokalemia

56
Q

What are the clinical uses of glucagon?

A

hypoglycemia

reducing biliary spasm

beta-blocker overdose

57
Q

What are the acute and chronic side effects of amiodarone?

A

acute: hypotension, QT prolongation, torsades
chronic: pulmonary fibrosis, hypo/hyperthyroidism

58
Q

What are the clinical features of digoxin toxicity?

A

arrhythmias (AV block, PVCs, VT)

nausea & vomitting

xanthopsia

59
Q

What are the indicated treatments for digoxin toxicity?

A

Digibind

treatment of hyperkalemia (EXCEPT CALCIUM)

magnesium (EXCEPT WITH AV BLOCK)

lidocaine to treat ventricular arrhythmias

60
Q

What are the contraindicated treatments for digoxin toxicity?

A

calcium

procainamide

cardioversion

61
Q

What are the indicated uses for ACEIs/ARBs?

A

systolic heart failure

anterior MI w/ low EF

diabetic nephropathy

62
Q

When are ACEIs/ARBs contraindicated?

A

pregnancy

bilateral renal artery stenosis

h/o angioedema

63
Q

Which supplements can cause mild platelet dysfunction?

A

ginseng

garlic

ginko biloba