Lecture 2 Pharmacodynamics and Pharmacokinetics Test 1 Flashcards

1
Q

Activation of protein receptors causes a ________________.

A

Conformational change

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2
Q

What is the drug effect related to?

A

The number of bound receptors.

Ie: Paralytics

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3
Q

____________ activates receptors by binding to them.

A

Agonist

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4
Q

What are 3 reversible bonds?

What bond is irreversible?

A

Ion (opposite charges), Hydrogen (electronegative atoms), and Van der Waals interaction (repulsive attraction)

Covalent bonds (strongest bond)

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5
Q

____________ binds to a receptor but does not activate the receptor, the get in the way of the endogenous ligand.

A

Antagonist

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6
Q

Increasing amounts progressively inhibit the agonist and shift the dose-response curve to the right.

A

Competitive antagonism

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7
Q

Even high concentrations of agonist can’t cause the agonist event.

A

Noncompetitive antagonism

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8
Q

Binding to a receptor (usually at agonist site).
Causes less response than the agonist even at a supramaximal dose.

A

Partial Agonist

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9
Q

Compete for the same site as the agonist but produces the opposite effect.

A

Inverse Agonist

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10
Q

Even high concentrations of agonists can’t cause the agonist event.

A

Noncompetitive antagonism

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11
Q

The number of receptors are not __________.

A

Static

Receptors can increase or decrease depending on comorbidity and drug therapy

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12
Q

What is tachyphylaxis?

A

Quick tolerance, down-regulation of receptors.

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13
Q

In pheochromocytoma, there is a ___________ in beta receptors in response to an increase in ____________.

A

decrease; catecholamines

Tolerance builds up

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14
Q

Receptors are classified by _____________.

A

Location

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15
Q

What 3 areas can receptors be located?

A

Lipid Bilayer
Intracellular Proteins
Circulating Proteins

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16
Q

Most of the anesthetic drugs that we give have receptors located in the _____________.

Examples?

A

Lipid Bilayer (Membrane Bound)

Opioids, BZDs, Beta-blockers, catecholamines, NMBD.

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17
Q

What are examples of drugs that bind to intracellular proteins?

A

Insulin, Steroids, Milrinone

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18
Q

What are examples of drugs that bind to circulating proteins?

A

Anticoagulants

Anticoagulants that are free or unbound will cause drug effect

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19
Q

What is the quantitative study of injected and inhaled drugs and their metabolites? What the body does to the drug.

What are the 4 components?

A

Pharmacokinetics

Absorption
Distribution
Metabolism
Excretion

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20
Q

Pharmacokinetics determines the concentration of the drug in the ____________ and at the _______________. This varies significantly from patient to patient.

A

Plasma and Effector Site

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21
Q

What is the one-compartment model?

A

Immediately after drug injection, the concentration of the drug is diluted by plasma in a central compartment, resulting in a small volume of distribution, and excreted immediately.

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22
Q

What is the vessel-rich group?

A

A small percentage of the body mass (brain, kidney, heart, lungs) that makes up a large percentage of cardiac output.

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23
Q

What is the two-compartment model?

A

The drug goes into a central compartment and then peripheral compartments (muscles, fats, tendons, ligaments).

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24
Q

For plasma protein receptors, what do acidic drugs bind to?

What do alkalotic drugs bind to?

A

Acidic drugs bind to albumin.

Alkalotic drugs bind to Alpha 1- Acid Glycoprotein.

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25
Q

Only __________ drug can cross cell membrane (distribution) and can determine the concentration available to receptor (potency)

A

Free unbound drug

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26
Q

Name factors that can decrease plasma protein.

A

Age
Hepatic Disease
Renal Failure
Pregnancy
Burns
Sepsis

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27
Q

If the normal free fraction of the drug is 2% and half the plasma proteins are lost, then the free fraction of the drug is _______%.

A

4%, it doubles.

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28
Q

Poor protein binding and lipophilic drugs have a ____________.

Examples

A

Greater Volume of Distribution (escapes plasma)

Examples: Thiopental and Diazepam

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29
Q

Highly protein-bound drugs to plasma protein will result in a ____________.

Examples

A

Smaller Volume of Distribution (stays in plasma)

Example: Warfarin

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30
Q

What is metabolism?

A

Usually conversion of an active drug to an inactive drug from lipid-soluble drugs to water-soluble and inactive metabolites (usually). Then kidneys pee it off.

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31
Q

What are some active metabolites?

A

Diazepam (Valium)
Propanolol (Inderal)
Morphine
Prodrugs such as Codeine

32
Q

How are most anesthetic drugs metabolized?

What are three other ways drugs are metabolized?

A

Through the Hepatic Microsomal Enzymes.

Plasma (Hoffman Elimination, ester hydrolysis)
Kidney
Tissue Esterase (GI Tract, Placenta)

33
Q

What does phase 1 metabolism involve?

What does phase 2 metabolism involve?

A

Phase 1: Increase polarity and prepare for phase II reactions
Oxidation
Reduction
Hydrolysis

Phase 2: Covalently link with a high polar molecule to become water soluble
Conjugation

34
Q

What is the large family of hepatic microsomal enzyme called consisting of 10 isoforms that are membrane-bound and contain a heme cofactor?

A

CYP 450

35
Q

What specific enzyme makes up 60% of CYP 450 activity and metabolizes over half of the drugs?

A

CYP3A4

36
Q

What drug will induce hepatic microsomal enzymes?

A

Phenobarbital

Drugs like opioids and BZD will have less effect

37
Q

What food will inhibit hepatic microsomal enzymes?

A

Grapefruit Juice

Increases concentration of drug/ toxicity levels

38
Q

Acute ingestion of alcohol will require the patient to receive ____________ anesthetics.

Chronic use of marijuana will require the patient o receive _____________ anesthetics.

A

Less (acute EtOH intake) Dr. Kane correction email

More (chronic marijuana)

39
Q

For most anesthetic drugs, the hepatic clearance is __________.

The rate is proportional to ____________.

A

Constant

Concentration (More Drug/More Clearance to a certain point since the liver capability is not unlimited)

40
Q

What is the rate of drug metabolism equation?

What are the two limitations to this equation?

A

Rate = Cardiac Output (Concentration Inflow - Concentration Outflow)

Flow limitation (Cardiac output) and capacity limitation (liver’s metabolizing ability)

41
Q

What are the three things involved in Renal Clearance?

A
  1. GFR
  2. Active Tubular Secretion
  3. Passibe Tubular Reabsorption
42
Q

Differentiate between Elimination Half Time vs Elimination Half-Life.

A

Elimination half-time is the time necessary to eliminate 50% of the drug from PLASMA after a bolus dose.

Elimination half-life is the time necessary to eliminate 50% of the drug from BODY after a bolus dose.

43
Q

You give 100 mcg of drug A. E 1/2 is 10 minutes. In 20 minutes what will plasma concentration be?

If you reinject 100 mcg of drug A, 20 minutes later what will the plasma concentration be?

A

25 mcg

31 mcg

44
Q

What is the time to a 50% decrease after infusion is discontinued?

A

Context Sensitive Half-Time

45
Q

What drugs have a short context-sensitive half-time?

A

Sufentanil
Alfentanil
Propofol

46
Q

What drugs have a long context-sensitive half-time?

A

Fentanyl
Thiopental

47
Q

What does it mean when the pK (dissociation constant) and pH are identical?

A

50% of the drug is ionized and 50% of the drug is non-ionized.

48
Q

What drug is a weak acid?

What drug is a weak base?

A

Weak acid: Barbituates, Thiopental

Weak bases: Local Anesthetics, Opioids

49
Q

Acids ionized in an _____________ environment.

Bases ionized in an _____________ environment.

A

Alkalotic

Acidic

50
Q

Describe non-ionized drug molecules in terms of their
Pharmacological Effect:
Solubility:
Cross lipid barriers:
Renal Excretion:
Hepatic metabolism:

A

Describe non-ionized drug molecules in terms of their
Pharmacological Effect: Active
Solubility: Lipids
Cross lipid barriers: Yes
Renal Excretion: No
Hepatic metabolism: Yes

51
Q

Describe ionized drug molecules in terms of their
Pharmacological Effect:
Solubility:
Cross lipid barriers:
Renal Excretion:
Hepatic metabolism:

A

Describe ionized drug molecules in terms of their
Pharmacological Effect: Inactive
Solubility: Water
Cross lipid barriers: No
Renal Excretion: Yes
Hepatic metabolism: No

52
Q

Weak acid (pK 7.6) is put in a basic pH (blood 7.8). Ionized or non-ionized?

A

Ionized

Because it is a weak acid, pK will go after the pH.
pH - pK
7.8 - 7.6 = +0.2

53
Q

Weak base (pK 8.0) is put in basic pH (blood 7.2) Ionized of non-ionized?

A

Ionized

Because it is a weak base, pK will go before the pH.
pK - pH
8.0 - 7.2 = +0.8

54
Q

Spinal Anesthetic is a weak base (pK 7.3), fetal pH is 6.8, and the mother’s pH is 7.4. Will the drug be ionized or non-ionized in the fetus and mom?

A

The anesthetic will be ionized in the baby, the drug will be trapped in the fetus.
The anesthetic will be non-ionized in the mom, the drug will be active.

Because spinal anesthetic is a weak base pK will go before pH
pK - pH
Fetus: 7.3 - 6.8 = +0.5
Mom: 7.3 - 7.4 = -0.1

55
Q

Pt with an ischemic foot requested an ankle block. Will surgical anesthetic work? An opioid is a weak base with a pK of 8.0.

Normal Tissue pH = 7.4
Ischemic Tissue pH = 6.6

A

No, a surgical anesthetic will not work. The drug will be ionized in normal tissue and ischemic tissue.

With a weak base, pK is before pH.
Normal Tissue: 8.0 - 7.4 = +0,6 (ionized)
Ischemic Tissue: 8.0 - 6.6 = +1.4 (very ionized)

56
Q

What the drug does the to the body. This is figured out by measuring concentrations at different pharmacological responses.

A

Pharmacodynamics

57
Q

There is individual variability in pharmacodynamics in the elderly due to what 3 factors?

A

Decrease Cardiac Output to the Brain and Liver
Decrease Protein Binding
Increase Body Fat

58
Q

Individual variability in pharmacodynamics includes _______ and ___________.

A

Enzyme activity
Genetic Disorders

59
Q

Concentration vs Response.

A

Potency

Less Drugs with more effect = more potent

60
Q

The ability of a drug to produce a clinical effect.

A

Efficacy

61
Q

Time to drug effect, the lag time between administration (plasma concentration) and effect.

A

Relative Potency

62
Q

The dose required to produce effect in 50% of patients.

A

ED50

63
Q

The dose required to produce death in 50% of patients.

A

LD50

64
Q

Ration between LD50 and ED50

A

Therapeutic Index (T.I.)

65
Q

How drug molecules are structured in 3D.

A

Stereochemistry

66
Q

Molecules with an asymmetric center, usually related to the way carbon molecules are bonded.

A

Chiral compounds

67
Q

These structures are chemically identical that are mirror images of each other and can not be superimposed.

A

Enantiomers

68
Q

In terms of rotation of light in solution, what is the right rotation called?

Left Rotation?

A

Right rotation: Dextrorotary or R (Rectus)

Left rotation: Levorotary or S (Sinister)

69
Q

Drug mixture with optical activity of equal compounds that can exhibit different ADME. One enantiomer is active and the other is inactive or has more side effects.

A

Racemic Mixtures

70
Q

What fraction of drugs are racemic?

A

1/3

71
Q

___ - Enantiomer of Ketamine is more potent had has less delirium.

A

S

72
Q

L-Bupivacaine has less _____________ .

A

Cardiac Toxicity

73
Q

What isomer of atracurium lacks histamine effects?

A

Cistracurium

74
Q

What is the isomer of albuterol that does not cause tachycardia?

A

Xopenex (But not as efficacious as albuterol)

75
Q

With pharmacogenetic testing, we look for variants in genes that code for _______, ________, and ________.

A

Drug-metabolizing enzymes
Drug targets
Immune Proteins