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Pharm > Pharmacokinetics > Flashcards

Pharmacokinetics Flashcards

1
Q

What relationship does pharmacokinetics describe?

A

dose-concentration

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2
Q

What relationship does pharmacodynamics describe?

A

concentration-effect

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3
Q

Pharmacokinetics = what the ___ does to ___

A

body does to the drug

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4
Q

What are the 4 components of pharmacokinetics?

A

Absorption
Distribution
Metabolism
Excretion

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5
Q

What is Fick’s Law of Diffusion?

A

rate of diffusion = concentration gradient * surface area* diffusion coefficient
/membrane thickness

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6
Q

The rate of diffusion is directly proportional to:

A

concentration gradient, surface area, diffusion coefficient

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7
Q

The rate of diffusion is inversely proportional to:

A

membrane thickness

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8
Q

Define bioavailability

A

Fraction of unchanged drug that reaches the systemic circulation following administration by any route

If the entire amount of a drug is absorbed into systemic circulation = 100% bioavailability

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9
Q

What is the equation for bioavailability?

A

F = (bioavailable dose/administered dose) * 100

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10
Q

Where is the principle site of absorption for oral meds?

A

Small intestine (large SA)

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11
Q

Bioavailability of oral meds

A

unreliable –> 5-100%

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12
Q

pH of the small intestine

A

7-8

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13
Q

pH of the stomach

A

1.5-2.0

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14
Q

Where do the veins in the mouth drain?

A

SVC

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15
Q

Bioavailability of sublingual meds

A

60-100%

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16
Q

What routes of administration are not subject to first pass hepatic metabolism?

A

sublingual (mouth veins drain into SVC)
intranasal
sometimes rectal
parenteral

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17
Q

Bioavailability of intranasal meds

A

up to 95%

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18
Q

Bioavailability of rectal meds

A

30-100%

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19
Q

The ____ rectum is more subject to first pass metabolism

A

proximal

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20
Q

What properties must transdermal drugs have?

A

lipid and water soluble
MW<1000 (fairly small)
dose <10mg in 24hrs
pH 7-9

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21
Q

Bioavailability of IV meds

A

100%

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22
Q

Bioavailability of SQ and IM meds

A

75-100%

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23
Q

What percentage of the adult male body is water?

A

60%

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24
Q

What percentage of the adult female body is water?

A

50%

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25
Q

What percentage of an infant’s BW is water?

A

70%

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26
Q

What percentage of an elderly person’s BW is water?

A

50-55%

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27
Q

Volume of total body water

A

42L

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28
Q

Volume of water in ECF

A

14L (~20% BW)

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29
Q

Volume of water in plasma

A

4L (~5%)

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30
Q

Volume of water in interstitial fluid

A

10L (~15%)

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31
Q

Volume of water in ICF

A

28L (~40% BW)

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32
Q

Define k12

A

rate constant = constant rate at which a drug moves

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33
Q

Define k21

A

rate of movement from the peripheral to central compartment

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34
Q

List the organs in the central compartment

A

lungs
heart
brain
liver
endocrine glands
kidney

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35
Q

List the organs/body parts in the peripheral compartment

A

muscle
skin
fat

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36
Q

The volume of distribution (Vd) relates:

A

amount of drug given to the plasma concentration

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37
Q

What is the equation for Vd

A

amount of drug / desired plasma concentration

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38
Q

What is the most common form of molecule movement in anesthesia?

A

lipid diffusion (most drugs have to cross the BBB which is a lipid membrane)

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39
Q

What drive aqueous diffusion?

A

concentration gradient

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40
Q

Describe a substance that moves via aqueous diffusion

A

lipid insoluble
hydrophilic
MW up to 30,000 (smaller)

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41
Q

What does active transport require?

A

sodium pump which utilizes ATP to move substances against their concentration gradient

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42
Q

Define endocytosis

A

phagocytosis (solids) or pinocytosis (liquids) –> the wall of a membrane engulfs the molecule to move it into the cell against its concentration gradient

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43
Q

What type of drugs bind to albumin?

A

acidic

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44
Q

List the factors that decrease albumin in the body

A

renal dz
liver dz
old age
malnutrition
pregnancy

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45
Q

What effect will a decrease in albumin have on drugs in the body?

A

a decrease in albumin results in an increase in the amount of free drug

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46
Q

What type of drugs bind to AAG?

A

basic (e.g. local anesthetics)

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47
Q

What is AAG?

A

alpha 1 acid glycoprotein

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48
Q

What factors increase AAG in the body?

A

surgical stress
MI
chronic pain
RA/inflammation
old age

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49
Q

What factors decrease AAG in the body?

A

neonates
pregnancy (3rd trimester)

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50
Q

What is the relationship between Vd and protein binding?

A

Vd is inversely proportional to the amount of protein binding

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51
Q

What is the equation for finding the free fraction of a drug?

A

(new value - old value)/old value x 100

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52
Q

What types of molecules have good lipid solubility?

A

nonpolar
nonionized

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53
Q

Are ionized molecules generally lipophilic or hydrophilic?

A

hydrophilic (do not readily cross membranes)

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54
Q

What effect does ionization have on particles with similar charges?

A

similar charges repel each other

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55
Q

For a drug to be eliminated through the renal system, it needs to be (ionized/nonionized)?

A

ionized

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56
Q

For a drug to be metabolized it needs to be (ionized/nonionized)?

A

nonionized

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57
Q

Define pKa

A

dissociation constant = the pH at which 50% of the drug is ionized and 50% of the drug is nonionized

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58
Q

What determines ionization?

A

the degree of ionization of a drug depends on its dissociation constant (pKa) and the pH of the blood

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59
Q

What kind of acids/bases do not dissociate?

A

strong acids and strong bases

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60
Q

Weak acids and weak bases exist in solution as ____

A

salts

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61
Q

Weak acids form salts with…

A

positively charged ions (Na+, Mg+, Ca++)
e.g. sodium thiopental, sodium nitroprusside

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62
Q

Weak bases form salts with…

A

negatively charged ions (Cl-, sulfate SO2-)
e.g. morphine sulfate, lidocaine hydrochloride

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63
Q

Weak acids like to (accept/donate) protons

A

donate

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64
Q

If you put an acidic drug in a basic solution, what happens to the drug?

A

it becomes more ionized (less of the drug is in the active form)

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65
Q

If you put an acidic drug in an acidic solution, what happens to the drug?

A

it becomes more nonionized (more of the drug is in the active form)

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66
Q

As the pH decreases, what happens to the H+ concentration?

A

increases

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67
Q

Weak acids become more (ionized/nonionized) when the pH falls

A

nonionized/more active at lower pH

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68
Q

The higher the pKa of a weak acid, the greater the amount of drug exists in the (ionized/nonionized) form in the body.

A

nonionized/active
ACID gets you HIGH

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69
Q

What is the range for the pKa of acids?

A

2.3-11.2

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70
Q

Define ANI BIN

A

acids: nonionized ——— ionized
bases: ionized ———- nonionized
used to compare two acids/two bases to determine which will exist in greater concentration at physiologic pH

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71
Q

Weak bases like to (accept/donate) protons

A

accept

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72
Q

If you put a basic drug in an acidic solution, what happens to the drug?

A

it becomes more ionized (less active)

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73
Q

If you put a basic drug in a basic solution, what happens to the drug?

A

it becomes more nonionized (more active)

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74
Q

What happens to basic drugs as the pH increases?

A

basic drugs become more nonionized/active at higher pHs

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75
Q

What is the range for the pKas of weak bases?

A

2.6-9.8

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76
Q

The lower the pKa of a weak base, the greater the amount of drug in the (ionized/nonionized) form at physiologic pH?

A

nonionized/active (BASES go LOW)

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77
Q

Define metabolism

A

biotransformation; the conversion of the parent drug into secondary molecules

end products are usually inactive/water soluble to be excreted by kidneys/liver

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78
Q

Where is the primary site of biotransformation/metabolism?

A

liver
other sites=plasma, lungs, kidney, GI tract, placenta

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79
Q

Describe phase 1 reactions

A

aka modification
convert a parent drug into more polar metabolites through oxidation, reduction, and/or hydrolysis

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80
Q

Describe oxidation

A

involves the loss of electrons (catalyzed by cyto P-450)

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81
Q

Describe reduction

A

involves the addition of electrons (catalyzed by cyto P-450)

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82
Q

Describe hydrolysis

A

breaking a compound into 2 parts by adding water (by nonspecific esterases and pseudocholinesterase)
*most anesthetic drugs involve hydrolysis in the plasma

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83
Q

List some drugs that undergo hydrolysis

A

remifentanil
succinylcholine
esmolol
ester local anesthetics

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84
Q

Describe phase 2 reactions

A

conjugation = couples a parent drug or a phase 1 metabolite with an endogenous substrate to form a highly polar, higher molecular weight (water soluble) end product that can be eliminated in the urine (via glomerular filtration)

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85
Q

What makes premature infants unique when it comes to drug metabolism?

A

immature liver enzymes
decreased conjugation
–> drugs that are metabolized this way can potentially be toxic to infants

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86
Q

What are the three types of phase 2 reactions?

A

glucuronidation (via glucuronosyl transferases)
sulfonation (sulftransferases)
acetylation (N-acetyltransferases, NAT)

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87
Q

Products of phase 2 reactions have (little/significant) biologic activity

A

little or none

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88
Q

Where are the hepatic microsomal enzymes located?

A

hepatic smooth ER
(also found in kidneys and GI tract)

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89
Q

What is the main hepatic microsomal enzyme?

A

Cytochrome P-450 –34A and 2D6 isoforms

90
Q

What does it mean if a substance is an “inducer” of microsomal enzymes?

A

inducers INCREASE clearance, REDUCE half-lives of drugs metabolized by the enzyme
-more enzyme is synthesized for the action
-may require MORE FREQUENT re-dosing to maintain desired concentration

91
Q

What does it mean if a substance is an “inhibitor” of microsomal enzymes?

A

inhibitors DECREASE clearance, INCREASE the half-lives of drugs metabolized by the enzyme
-competition for the enzyme occurs
-may require LESS FREQUENT re-dosing to maintain desired concentration

92
Q

List some drugs metabolized by CYP-34A

A

fentanyl
alfentail
sufentanil
methadone
lidocaine
ropivacaine
bypuvacaine
midazolam
diazepam
alcohol

93
Q

List and describe some inducers of CYP-34A

A

increase clearance/decrease half-lives/more frequent re-dosing required
ethanol
carbamazepine
rifampin
St. John’s Wart
tamoxifen
barbiturates

94
Q

List and describe some inhibitors of CYP-34A

A

decrease clearance/increase half-lives/less frequent re-dosing required
ketoconazole
fluconazole
cimetidine
erythromycin
grapefruit juice
SSRI

95
Q

List some drugs metabolized by CYP-2D6

A

codeine
morphine
oxycodone
hydrocodone
zofran

96
Q

List and describe some inducers of CYP-2D6

A

increase clearance/reduce half-lives/more frequent re-dosing
phenytoin
carbamazepine
dexamethasone

97
Q

List and describe some inhibitors of CYP-2D6

A

decrease clearance/increase half-lives/less frequent re-dosing
isoniazid
SSRI
quinidine

98
Q

What is unique about red haired patients?

A

appears to be a distinct phenotype linked to increased anesthetic requirements

99
Q

What is one trait unique to CYP-2D6 deficient individuals?

A

decreased response to codeine

100
Q

What is one trait unique to CYP-2D6 inducer individuals?

A

decreased response to zofran

101
Q

What is one trait unique to individuals with atypical cholinesterase?

A

lack the normal amount of the enzyme needed to breakdown succinylcholine

102
Q

How would a plasma concentration curve of a lipid soluble drug appear different from other drugs?

A

Very steep - drug doses are adjusted to be higher due to the rapid movement across membranes

103
Q

Define the distribution phase

A

AKA alpha phase of elimination; involves the redistribution of drug from the plasma and vessel rich group to the less perfused tissues of the peripheral compartment

104
Q

Define the elimination phase

A

AKA beta phase of elimination; after redistribution slows, we get slow continuous elimination from the central compartment
affected by blood flow

105
Q

After how many half-times is a drug considered to be cleared from the body?

A

5 - 96.9% cleared

106
Q

Define elimination half-time

A

time necessary for the plasma concentration to decrease to 50% during the elimination phase

107
Q

Define elimination half-life

A

time necessary for 50% of the drug to be removed from the body after rapid IV administration

108
Q

Define context-sensitive half-time

A

time necessary for the plasma concentration to decrease to 50% after discontinuing an infusion of a specific duration
-considers distribution, metabolism, and duration of continuous IV administration
-the longer you run a drip, the longer it may take to wear off

109
Q

Describe zero order kinetics

A

occurs when the plasma concentration of drug exceeds the capacity of the metabolizing enzymes; results in metabolism of a constant amount of drug per unit time regardless of plasma concentration
*dangerous because you can become toxic quickly

110
Q

Name three drugs that use zero order kinetics

A

Alcohol
Aspirin
Phenytoin

111
Q

Describe first order kinetics

A

a constant fraction/proportion of available drug is metabolized in a given time period; dependent on the plasma concentration
(most drugs use this pathway)
*at least 50% of drug metabolized every 2hrs

112
Q

What are the 2 main organs for elimination?

A

kidneys (drug excreted in urine unchanged)
liver (drugs bio transformed for elimination)

113
Q

Define clearance

A

the volume of plasma cleared of a drug by renal excretion/liver metabolism per unit time

114
Q

What does clearance depend on?

A

properties of the drug
body’s capacity to eliminate it

115
Q

Define steady state

A

the point when drug elimination is equal to the rate at which the drug is made available

aka when a stable plasma volume concentration is achieved

116
Q

What is the equation for hepatic clearance?

A

clearance = Q x ER

Q=blood flow in L/min
ER=extraction ratio from 0-1

117
Q

Define hepatic clearance extraction ratio (ER)

A

the fraction of drug coming into the liver that is extracted

range of 0-1; 0=no metabolism, 1=maximal metabolism (Vm)

118
Q

What is the equation for extraction ratio?

A

ER= (C-inflow - C-outflow) / C-inflow

C-inflow=drug concentration coming in
C-outflow=drug concentration leaving

119
Q

Define perfusion-dependent eliminiation

A

high hepatic extraction ratio (>0.7)
depends on blood flow
minimal influence from hepatic enzymes

120
Q

Define capacity-dependent elimination

A

low extraction ratio (0.3 or lower)
blood flow has no effect on clearance

121
Q

Name some drugs with low ERs

A

Diazepam
Lorazepam
Methadone
Phenytoin
Rocuronium
Theophylline
Thiopental

(low ER means blood flow to the liver does not affect clearance)

122
Q

Name some drugs with intermediate ERs

A

Alfentanil
Methohexital
Midazolam
Vecuronium

123
Q

Name some drugs with high ERs

A

Bupivacaine
Diltiazem
Fentanyl
Ketamine
Lidocaine
Meperidine
Metoprolol
Morphine
Naloxone
Nifedipine
Propofol
Propranolol
Sufentanil

124
Q

What 3 processes are involved in renal clearance?

A

glomerular filtration
passive tubular resorption
active tubular secretion

125
Q

(Ionized/nonionized) substances are going to be reabsorbed

A

nonionized

126
Q

What is the equation for CrCl?

A

((140-age) x weight in kg) / (72 x SCr)

*multiply by 0.85 for females

127
Q

What is renal filtration dependent on?

A

amount of free unbound drug
GFR (determined by CrCl)

128
Q

(Protein bound/non-protein bound) drug free cross from plasma to glomerular filtrate

A

non-protein bound

129
Q

A change in urine pH can affect what process?

A

renal excretion

130
Q

Name some drugs with significant renal excretion

A

Aminoglycosides
Atenolol
Cephalosporins
Digoxin
Edrophonium
Nadolol
Neostigmine
Nor-Meperidine
Pancuronium
PCN
Pyridostigmine
Rocuronium

131
Q

In the elderly, what characteristics affect clearance?

A

decreased GFR
decreased liver blood flow
increased fat (increased Vd)

132
Q

In neonates, what characteristics affect clearance?

A

immature liver enzymes
poor renal function during first year of life

133
Q

Clearance is directly proportional to:

A

Blood flow to cleaning organ
Extraction ratio
Drug dose

134
Q

Clearance is inversely proportional to:

A

Half-life
Drug concentration in the central compartment

135
Q

What is the equation for loading dose?

A

loading dose = Vd x (desired plasma concentration / bioavailability)

136
Q

Which anesthetic is least likely to undergo fetal ion trapping and why?

A

Chloroprocaine is least likely d/t high pKa and rapid metabolism in mother’s blood

137
Q

Fetal pH is usually (higher/lower) than maternal pH. This has implications for what process?

A

lower (slightly more acidic); ion trapping

138
Q

A drug with a pKa close to physiological pH is likely to experience (great/minimal) effects on ionization with changes in pH?

A

great effects - drugs with a pKa close to 7.4 will see great shifts with changes in pH

139
Q

Ibuprofen is a (weak/strong) acid.

A

weak (pKa 4.4)

140
Q

Ibuprofen is a non-selective Cox inhibitor. What side effects can this drug produce?

A

GI upset, renal effects, bleeding

141
Q

Describe the effect of Tagamet on hepatic enzymes:

A

Tagamet = Cimetidine
H-2 blocker, CYP 3A4 inhibitor

142
Q

Compare absolute and relative bioavailability

A

absolute = amount of drug from a formulation that reaches systemic circulation relative to an IV dose

relative = amount of a drug from a formulation that reaches the systemic circulation relative to a non-IV formulation

143
Q

Why is Epi often administered in combination with local anesthetics?

A

decrease systemic absorption, vasoconstrict to keep drug at site of action

144
Q

Rank tissues from highest to lowest blood flow:

A

I Think I Can Please Everyone But Susie and Sally
intravenous
tracheal
intercostal
caudal
paracervical
epidural
brachial plexus
sciatic/subarachnoid
subcutaneous

145
Q

What situation can lead to ion-trapping for a base?

A

basic drug into basic environment, then shift environment to more acidic so the drug cannot move back

146
Q

What situation can lead to ion-trapping of an acidic drug?

A

acidic drug into acidic environment, then shift the environment more basic so the drug cannot move back

147
Q

Define a ligand

A

a molecule that binds to a receptor to produce a biologic response; may be endogenous or exogenous

148
Q

List the types of molecular bonds from weakest to strongest

A

Van de Waals
Hydrogen
Ionic
Covalent

149
Q

What is the law of mass action?

A

the velocity of a reaction depends on the concentrations of the reactants; when a chemical reaction reaches equilibrium, the concentrations of the chemicals involved bear a constant relationship to each other, which is described by the equilibrium constant

150
Q

The dose-response curve is time (dependent/independent).

A

independent; time has nothing to do with it, you are looking solely at the dose required to achieve a single desired effect

151
Q

Define potency

A

concentration (dose) of a drug needed to produce an effect (response)

152
Q

Describe how a drug that is more potent would appear on a dose-response curve compared to a less potent drug.

A

The more potent drug would be shifted to the LEFT on the x-axis (dose); a lower dose is required to achieve the desired response

153
Q

Define EC50

A

the effective concentration at 50%; the dose/concentration required to produce 50% of the desired response

154
Q

Define Emax

A

the effective concentration at 100%; the dose/concentration required to achieve maximal effect

155
Q

What does slope describe in the dose-response curve?

A

slope is related to drug-receptor affinity and the number of receptor complexes required for a specific effect; the steeper the slope, the more potent the drug at small increases in concentration

156
Q

Describe the DRC of a full agonist

A

starts at the x-axis and reaches Emax

157
Q

Describe the DRC of a partial agonist

A

Starts at the x-axis but does not reach Emax

158
Q

Describe the DRC of an antagonist

A

Emax=0, EC50=0; the desired response is not achieved

159
Q

Describe the DRC of a reverse antagonist

A

Dips below the x-axis; reverses the desired effect

160
Q

Define competitive antagonism

A

reversible; increased concentration of an agonist can offset the effects/kick the antagonist off the receptors; Emax and EC50 = 0

161
Q

Define noncompetitive atagonism

A

irreversible; long duration of action; increased concentration of agonist cannot overcome the effect; Emax and EC50 = 0

162
Q

Define an inverse agonist

A

binds to a receptor and produces the opposite effect of an agonist at the receptor

163
Q

Define “therapeutic window”

A

the dose range of a drug between a therapeutic effect and a toxic effect

164
Q

Define “therapeutic window”

A

the dose range of a drug between a therapeutic effect and a toxic effect

165
Q

What is the equation for therapeutic index?

A

LD50/ED50
or
TD50/ED50

166
Q

The larger the therapeutic index, the (more/less) safe the drug

A

more

167
Q

Define drug addition

A

the combination of the effects of 2 drugs (1+1=2)

168
Q

Define drug synergism

A

the combination of the effects of 2 drugs is greater than the individual effect (they work at different receptors)
(1+1=3)

169
Q

Define drug potentiation

A

the addition of one drug to another increases the effect of the first drug (1+0=3)

170
Q

Define drug antagonism

A

the effects of two drugs given in combination cancel each other out

171
Q

Define tachyphylaxis

A

-an acute rapid decrease in response to a drug after its administration
-most often sudden and not dose-dependent
-may be d/t exhausted receptors
-cannot achieve a full effect of the drug

172
Q

Define chirality

A

molecules with 3D asymmetry (e.g. your hands)

173
Q

Define enantiomerism

A

pairs of molecules existing in 2 forms that are mirror images

174
Q

Define a racemic mixture

A

a 50/50 mixture of left- and right-handed enantiomers of a chiral molecule

175
Q

Describe the process of a ligand gated ion receptor

A

binding of the NT/drug causes a conformational change in the receptor –> ion channel opens or closes

176
Q

Which method of signal transduction is the fastest?

A

ligand gated ion receptors

177
Q

Give 3 examples of ligand gated ion receptors

A

nicotinic
NMDA
GABA A

178
Q

Describe the process of a voltage-sensitive ion channel

A

depolarization causes ions to flow through pores (Na+, Cl-, K+, Ca++ channels

179
Q

Where are voltage-sensitive ion channels located?

A

neurons, skeletal muscle, endocrine cells

180
Q

What is the largest family of cell surface receptors in the body?

A

G-protein coupled receptors

181
Q

Describe the process of G-protein coupled receptors

A

activate or inhibit an enzyme, ion channel, or target receptor via second messengers within the cell

182
Q

Give 5 examples of G-protein coupled receptors in the body

A

hormones
catecholamines
opioids
anticholinergics
antihistamines

183
Q

What is the slowest method of signal transduction?

A

intracellular receptors

184
Q

Describe the process of an enzyme linked transmembrane receptor

A

enzymes cause a chemical change that stimulates an intracellular second messenger

(most are tyrosine kinases that phosphorylate the second messenger)

185
Q

Give 3 examples of enzyme linked transmembrane receptors

A

insulin receptors
atrial natriuretic peptide
growth hormones

186
Q

Give 3 examples of intracellular receptors

A

steroid receptors
thyroid hormone receptors
phosphodiesterase inhibitors

187
Q

Give some examples of neurotransmitters

A

acetylcholine
dopamine
norepinephrine
epinephrine
histamine
serotonin
substance P
glutamate/aspartate
GABA (gamma-amino butyric acid)

188
Q

What is acetylcholinesterase?

A

enzyme that breaks down acetylcholine (ACh) into choline (which is reused) and acetate (which is eliminated); located within the nerve synapse

189
Q

Where is acetylcholine stored?

A

vesicles (until the neuron fires)

190
Q

Where is choline acetyltransferase located?

A

presynaptic/preganglionic nerve terminal

191
Q

Describe nitcotinic receptors

A

ion channel opens allowing intracellular influx of Na+; stimulated by ACh, succinylcholine, nicotine; blocked NDMRs and trimethaphan

192
Q

Where are nicotinic receptors located

A

NMJ, autonomic ganglia, CNS

193
Q

Which neurotransmitters stimulate nicotinic receptors?

A

acetylcholine
succinylcholine
nicotine

194
Q

Which substances block nicotinic receptors?

A

nondepolarizing neuromuscular blockers (@NMJ)
trimethaphan (@ autonomic ganglia)

195
Q

What type of receptor are muscarinic receptors?

A

G-protein coupled (5 subtypes - M1-M5)

196
Q

Where are muscarinic receptors located?

A

CNS
target organs of parasympathetic nervous system
(salivary & sweat gland secretion, pupillary constriction, increases GI paristalsis, slows conduction through SA and AV nodes)

197
Q

What substances stimulate muscarinic receptors?

A

acetylcholine and muscarine

198
Q

What substances block muscarinic receptors?

A

atropine
scopolamine
pilocarpine

199
Q

Name 3 catecholamines

A

dopamine
epinephrine
norepinephrine

200
Q

What are the central functions of dopamine?

A

memory, problem-solving
reward-pleasure behavior
inhibition of prolactin secretion
fine control of movement
N/V

peripheral functions=coronary and renal vasodilation

201
Q

What stimulates dopamine receptors? What are some side effects?

A

dopamine/L-dopa
side effects: euphoria, psychosis, orthostatic hypotension, nausea

202
Q

What are dopamine receptors blocked by? What are some side effects?

A

haloperidol/other antipsychotics, antiemetics (metaclopramide, droperidol)
side effects=parkinsonism, extrapyramidal reactions, hyperprolactinemia

203
Q

Name the 5 types of adrenergic receptors:

A

alpha-1, alpha-2, beta-1, beta-2, beta-3

204
Q

Where is histamine synthesized?

A

CNS, immune cells, GI tract

205
Q

What are the 3 types of histamine receptors and where are they located?

A

H1: vascular smooth muscle, bronchial smooth muscle, CNS
H2: stomach
H3: presynaptic cleft

206
Q

Where is serotonin found (2 locations)?

A

intestine (regulates intestinal movement)
raphe nucleus in brainstem (affects mood, cognition, sleep)

207
Q

How many types of serotonin receptors are there?

A

7
5-HT3 is most common in anesthesia

208
Q

What is a key antagonist of serotonin?

A

ondansetron (antiemetic working at 5-HT3 receptor)

209
Q

What substance is the primary NT produced by pain/temperature afferent peripheral neurons?

A

substance P

210
Q

Substance P acts on which receptors?

A

neurokinin receptors

211
Q

Name the NT that are associated with PONV:

A

dopamine
serotonin
acetylcholine
histamine
opioids
substance P

212
Q

Describe glutamate:

A

-primary brain excitatory NT
-most prominent brain NT
-acidic
-charged (does not cross BBB)

213
Q

Glutamine is synthesized from what substance?

A

glutamate (crosses BBB and is transformed)

214
Q

Describe the N-methyl-d-Aspartate receptor:

A

aka NMDA receptor
-receptor for glutamate
-non-specific cation channel (Na+ and Ca++ in; K+ out –> neuronal depolarization)
-requires coactivation with glutamate and glycine
-antagonists=dextromethorphan, ketamine, nitrous oxide, magnesium, methadone

215
Q

Describe GABA:

A

aka gamma amino butyric acid
-primary inhibitory NT in brain
-second most abundant NT in brain
-synthesized in presynaptic neuron from glutamate

216
Q

Describe how GABA-A receptors function:

A

ionotropic ligand-gated ion channels (allows passage of Cl-)
increased intracellular Cl- leads to hyperpolarization of the neuron (less likely to fire)

217
Q

What is allosteric regulation? What is one example of a receptor that utilizes this?

A

binding of a drug/chemical at a site distinct from the receptor’s primary allosteric site
example=GABA

218
Q

Name some positive allosteric modulators for GABA:

A

(enhance the affinity of the receptor for GABA)
barbiturates
propofol
etomidate
benzos
steroids

219
Q

Name some negative allosteric modulators of GABA:

A

(decreases the action of GABA)
flumazenil

220
Q

Describe how GABA-B receptors work:

A

G-protein mediated intracellular changes result in the opening of a K+ channel
K+ leaves the cell –> hyperpolarization –> inhibition

Pharm (19 decks)

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