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PHARMACOLOGY > M1: Ch4 Drug Metabolism & Excretion > Flashcards

M1: Ch4 Drug Metabolism & Excretion Flashcards

0
Q

Substance absorbed or ingested in food and drink or deliberately as drugs. Inadvertent or accidental exposure. Can provoke biologic responses the depend on conversion of the absorbed substance into an ____________.

A

Xenobiotics. Active metabolite.

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1
Q

Metabolized by same enzymatic pathways and transport systems that are utilized for dietary constituents.

A

Xenobiotics

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2
Q

Xenobiotics: many are ________ that, without metabolism, would not be efficiently eliminated and would accumulate in the body which may lead to possible ________.

A

Lipophilic. Toxicity.

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3
Q

Xenobiotics: most are subjected to metabolic pathways that convert these _________ into more _________ derivatives that are readily eliminated in ______ or _____.

A

Hydrophobic. Hydrophilic. Urine or Bile.

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4
Q

Metabolism & Excretion collectively named as this.

A

Biotransformation

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5
Q

Processes responsible for elimination of drug (parent and metabolite) from the body.

A

Metabolism & Excretion

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6
Q

Frequently but not universally less pharmacologically active.

A

Metabolite

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7
Q

Changes the chemical structure of a drug to produce a drug metabolite

A

Drug Metabolism

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8
Q

Lipophilic drug that has no metabolism and excretion is impossible

A

Metals & Toxins

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9
Q

Drug Disposition: more water soluble = easily ______.

A

Excretable

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10
Q

Phases of Metabolism

A

Phase I (Redox) & Phase II (Conjugation)

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11
Q

As you hydrolyze, it becomes more _______ and then ________.

A

Polar. Soluble.

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12
Q

Convert the parent drug to a more polar metabolite by introducing or unmasking a functional group. Often metabolites is inactive, although in some instances activity is only modified or even enhanced.

A

Phase I Redox

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13
Q

Act by causing the drug molecule to undergo oxidation or more rarely reduction.

A

Enzymes

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14
Q

If Phase I metabolites are sufficiently ________, they may be readily excreted.

A

Polar

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15
Q

Splitting a bond

A

Hydrolysis

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16
Q

Bonds that are cleaved in Phase I

A

Ester & Amide bonds

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17
Q

Undergoes Hydrolysis of the ester bond with the help of Acetylcholinesterase

A

Acetylcholine

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18
Q

Undergoes Hydrolysis of the ester bond with the help of Esterase. It becomes active once metabolize.

A

Acetylsalicylic acid

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19
Q

Bond used by Angiotensin

A

Peptide/Amide bond

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20
Q

A peptidase/amidase that causes hydrolysis to Angiotensin

A

ACE

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21
Q

Angiotensin I is activated to this which is a vasoconstrictor

A

A2

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22
Q

Enzyme used in converting A1 to A2

A

Angiotensinase

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23
Q

Has an amide bond and is an Anesthetic agent

A

Prilocaine

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24
Q

Remove alkyl group then increases polarity

A

N-Dealkylation

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25
Q

Major Reactions involved in Drug Metabolism

A

Oxidative & Hydrolysis Reactions

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26
Q

Oxidative Reactions

A

N-Deakylation, A-Deakylation, N-Oxidation, Aliphatic hydroxylation, S-Oxidation, Aromatic hydroxylation & Deamination “NANA SAD”

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27
Q

Many Phase I products are not eliminated rapidly and undergo a subsequent reaction in which an endogenous substrate is added.

A

Phase II Conjugation

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28
Q

Endogenous substrates. Combine with the newly incorporated functional group to form a highly polar conjugate.

A

Glucuronic acid, Acetic acid, Glutathionase, Amino acid & Sulfuric acid “GAGAS”

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29
Q

Hallmark of Phase II Metabolism

A

Conjugation/Synthetic Reaction

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30
Q

Conjugation Reactions in Phase II

A

Methylation, Acetylation, Glucuronidation & Sulfation “MAGS”

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31
Q

The most important of Phase II Conjugation reactions. Reaction does not proceed spontaneously. Requires its activated form.

A

Glucuronidation

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32
Q

Activated form of glucuronic acid

A

Glucuronic Acid Uridine Diphosphate

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33
Q

Drug that causes Grey baby syndrome

A

Chloramphenicol

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34
Q

When chloramphenicol is given without regard for infant’s diminished capacities for hepatic detoxification and renal elimination these will occur

A

Grey discoloration, Cyanosis, Hypothermia, Acidosis & Vomiting “G CHAV”

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35
Q

Immature activity of this enzyme in Grey Baby Syndrome

A

Glucuronosyl Transferase

36
Q

Xenobiotic Metabolic Enzyme for Phase I

A

Oxygenases

37
Q

Xenobiotic Metabolic Enzyme for Phase II

A

Transferases

38
Q

An anticonvulsant used in treatment of epilepsy is virtually insoluble in water

A

Phenytoin

39
Q

Phase I: Phenytoin ————> 4-OH-Phenytoin

A

Cytochrome P450 enzymes

40
Q

Phase II: 4-OH-Phenytoin ————-> 4-glucoronate

A

UDP glucuronosyltransferase

41
Q

Also terminates the biologic activity

A

Metabolism

42
Q

May also precede Phase I reactions

A

Phase II

43
Q

Site of cellular metabolism

A

Endoplasmic Reticulum

44
Q

Endoplasmic Reticulum: Phase I enzymes

A

FMOs, Ehs & CYPs “FEC”

45
Q

Endoplasmic Reticulum: Phase II enzymes

A

Conjugating enzymes, UGTs

46
Q

Enter the cell and embed in the lipid bilayer, where they encounter the Phase I enzymes.

A

Hydrophobic molecules

47
Q

Once oxidized, drugs are conjugated in the membrane by the

A

UGTs or by cytosolic transferases

48
Q

Carry out most drug Metabolism, produce conjugate substrates, transported through bile canalicular membrane then gut elimination.

A

Hepatocytes

49
Q

Enzyme Superfamily is the primary Phase I enzyme system involved in the oxidative metabolism of xenobiotics. Also are responsible for all or part of the metabolism and synthesis of a number of endogenous compounds such as steroid hormones and prostaglandin.

A

CYP450

50
Q

CYPs are most abundant in the

A

Liver

51
Q

Is the most abundantly expressed. Metabolism of 50% of clinically used drugs.

A

CYP3A4

52
Q

Rarely involved in metabolism of therapeutic drugs. Catalyze the metabolic activation of many protoxins and procarcinogens.

A

CYP1A, CYP1B, CYP2A, CYP2B & CYP2E

53
Q

CYP3A5 whose AA sequence is similar to that of CYP3A4 appears to possess roughly the same substrate specificity characteristics as (not present in all individuals)

A

CYP3A

54
Q

Hence, patients expressing both CYP3A4 and CYP3A5 have the potential to exhibit ___________ of CYP2A substrates as compared to individuals expressing only the CYP3A4 isoform.

A

Increased Metabolism

55
Q

Expressed only in the fetus and rapidly disappears following birth. Replaced by CYP3A4 and CYP3A5.

A

CYP3A7

56
Q

Second most common CYP isoform involved in human drug metabolism; most known for its propensity to exhibit genetic polymorphisms.

A

CYP2D6

57
Q

Metabolized several clinically important drugs with narrow therapeutic indices.

A

CYP2C9

58
Q

An antiepileptic agent

A

Phenytoin

59
Q

An anticoagulant

A

Warfarin

60
Q

Induce enzyme = _______ drug effect. Inhibit enzyme = ________ drug effect.

A

Decrease. Increase.

61
Q

General metabolizer

A

CYP3A4

62
Q

Study of the genetic basis for variation in drug response

A

Pharmacogenetics

63
Q

Employs tools for surveying the entire genome to assess multigenic determinants of drug response

A

Pharmacogenomics

64
Q

An individual’s response to a given drug depends on a complex interplay among many environmental and genetic factors

A

Environmental & Genetic factors

65
Q

A variation in the DNA sequence that is present at an allele frequency of 1% or greater in a population

A

Polymorphism

66
Q

Two major types of sequence variations

A

Single Nucleotide Polymorphism(SNPs) & Insertions/Deletions(Indels)

67
Q

In Asian, Isoniazid is considered as an _________ which may cause _________.

A

Rapid Acetylator. Hepatotoxicity.

68
Q

In American, Isoniazid is considered as an _________ which may cause ___________.

A

Fast Acetylator. Peripheral neuropathy.

69
Q

An anti-arrhythmic drug. Slow acetylators are much more likely to develop SLE like syndrome that has been described as a characteristic and therapy-limiting event associated with this drug. The culprit is polymorphism in __________.

A

Procainamide. N-acetyltransferase.

70
Q

Are more likely to have complete ulcer healing after therapy with ________(a proton pump inhibitor that reduces gastric acid) than are extensive metabolizers. A positive benefit. 2-3% caucasians & 20-30% asians.

A

CYP2C19 Polymorphism. Omeprazole.

71
Q

Drugs are transferred from the internal to the external environment. Thru what?

A

Excretion. Biliary system, Lungs, Intestines & Kidneys “BLIK”

72
Q

Is the primary organ of removal of drugs, especially for those that are water soluble and not volatile.

A

Kidney

73
Q

Three principal processes that determine the Urinary excretion of a drug

A

Glomerular filtration, Tubular secretion & Tubular reabsorption (passive-back diffusion) “GTT”

74
Q

Excretion of a weak acid may be accelerated by ______ the urine with _______.

A

Alkalinizing. Bicarbonate.

75
Q

Excretion of a weak base may be accelerated by ________ the urine with _________.

A

Acidifying. Ammonium chloride.

76
Q

The rate of urinary drug excretion will depend on its degree of binding protein

A

Vd

77
Q

The amount of drug that finally appears in the urine will represent a balance of _______, _______ & _______ drug.

A

Filtered. Reabsorbed. Secreted.

78
Q

Passage of xenobiotics from the blood into the liver normally is not restricted because the endothelium of the hepatic blood sinusoid behaves as a porous membrane. Hence, drugs with molecular weights ___________ those of most protein molecules readily reach the hepatic extracellular fluid from the plasma.

A

Biliary excretion. Lower than.

79
Q

The physiochemical properties of most drugs are sufficiently favorable for ___________ that the compound will reenter the blood that perfuses the intestine and again to be carried to the liver.

A

Passive Intestinal Absorption

80
Q

Gases and other volatile substances that enter the body primarily through the respiratory tract can be expected to be excreted by this route. All volatile materials.

A

Pulmonary excretion

81
Q

Lipid insoluble compounds such as urea and glycerol

A

Sweat & Saliva

82
Q

More acidic than plasma, basic compounds like alkaloids may be somewhat more concentrated.

A

Human milk

83
Q

Examples of Alkaloids

A

Morphine & Codeine

84
Q

pH level of Milk

A

6.5

85
Q

Other factors of Human milk

A

Plasma binding, Lipid solubility & Molecular weight “PLM”

86
Q

Main organ for Drug Metabolism

A

Liver

87
Q

Main organ for Drug Excretion

A

Kidney

PHARMACOLOGY (8 decks)

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