22) Toxic substances Flashcards

1
Q

father of modern toxicology

A

Paracelsus

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2
Q

positive screens require drug confirmation method with…

A

Definitive or reference method (GC-MS or LC-MS)

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3
Q

2 steps of toxic drug test

A
  1. screening test; qualitative
  2. confirmatory test; quantitative
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4
Q

a cutoff value is ———- than the detection limit, but —— enough to detect drug use within a reasonable time frame

A

higher
low

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5
Q

————– are not always specific for the drug tested.

A

Immunoassays

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6
Q

significant factors the CLS should be familiar in reference to drug abuse screening

A

Detection limit
Specificity (lack of)
Cutoff values
Interpreting positive versus negative results

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7
Q

3 types of invalid urine specimens

A
  • adulteration
  • dilution
  • substitution
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8
Q

A specimen containing a substance that is not a normal constituent or containing an endogenous substance at a concentration that is not a normal physiological concentration

A

adulterated urine

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9
Q

Creatinine and specific gravity values that are lower than expected for human urine

A

dilute urine

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10
Q

Creatinine and specific gravity values that are so diminished or so divergent that they are not consistent with normal human urine

A

substituted urine

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11
Q

A specimen is considered to have been adulterated if it meets specific criteria established by the Substance Abuse and Mental Health Administration (SAMHSA):
- pH…
- nitrite…
- 5 substances present

A
  • pH <3 or ≥11
  • Nitrite concentration ≥ 500 ug/mL
  • Chromium (VI)
  • Halogens (bleach, iodine, fluoride)
  • Glutaraldehyde
  • Pyridine
  • Surfactant
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12
Q

creatinine concentration is <2 mg/dL and the specific gravity is ≤1.0010

OR

≥1.0200 on both the initial and confirmatory tests on two separate aliquots

A

substituted urine

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13
Q

Creatinine concentration is 2-20 mg/dL

and

Specific gravity is 1.0010-1.0030 on a single aliquot.

A

dilute urine specimen

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14
Q

urine adulteration test strip reactions

A
  • Creatinine
  • nitrite
  • glutaraldehyde
  • pH
  • specific gravity
  • bleach
  • pyridinium chlorochromate
  • oxidants
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15
Q

Intect® 7
AdultaCheck®
Alere Toxicology PLC

A

urine adulteration test strips

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16
Q

3 major effects of acetaminophen

A
  • anti-inflammatory
  • analgesic
  • antipyretic
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17
Q

Toxic doses, described as 2-3 times the maximum therapeutic dose, cause a serious and potentially fatal hepatotoxicity.

A

acetaminophen

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18
Q

mechanism of acetaminophen’s liver toxicity

A

saturation of enzymes catalyzing the normal conjugation reaction and results in the drug being metabolized by mixed function oxidases which produces a toxic metabolite that causes necrosis in the liver.

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19
Q

Blood samples should be obtained after 4 hours to ensure absorption is complete

A

acetaminophen

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20
Q

Not useful if the time of ingestion is unknown or unreliable

A

acetaminophen levels

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21
Q

Most commonly consumed drug in the world

A

aspirin

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22
Q

indications for aspirin use

A
  • Cardiovascular disorders
  • Colonic and rectal cancer
  • Alzheimer’s disease
  • Radiation-induced diarrhea
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23
Q

Repeated ingestion of fairly large doses

Syndrome associated with tinnitus (a high- pitched buzzing noise in the ears), vertigo, decreased hearing, and occasionally nausea and vomiting

A

salicylism

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24
Q

Follows an acute viral illness in children

Involves the liver and central nervous system (CNS)

Has a 20-40% mortality outcome.

A

Reye’s syndrome
(aspirin)

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25
Q

Causes several metabolic changes in the body (3 types of acid-base disorder)

A

salicylate poisoning

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26
Q

3 ways aspirin can cause acid-base disturbances

A
  1. resp alkalosis; hyperventilation
  2. resp acidosis; respiratory depression, decreased serum bicarb
  3. metabolic acidosis; accumulation of pyruvic acid, lactic acid, acetoacetic acid
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27
Q

Excessive elevation of body temperature >106.7°F

A

hyperpyrexia associated with aspirin poisoning

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28
Q

Can increase the effect of warfarin by displacing it from plasma proteins in addition to its effect on platelets

A

aspirin

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29
Q

Trinder reaction

A

aspirin

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30
Q

90% metabolized, 5-10% excreted unchanged in expired air and urine

A

ethanol

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31
Q

Metabolism of ethanol in the liver involves successive oxidations:

A
  • First to acetaldehyde by the enzyme alcohol dehydrogenase
  • Then to acetic acid by aldehyde dehydrogenase
  • The intermediate metabolite acetaldehyde is a reactive and toxic compound that may contribute to the hepatotoxicity
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32
Q

can barely walk, vomiting, possibility of LOC

A

0.20 - 0.249%

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33
Q

alcohol poisoning

A

0.25 - 0.399%

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34
Q

onset of coma, death with alcohol

A

> 0.4%

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35
Q

The effect of CO on the oxygen dissociation curve is a shift to the ——-, which decreases the release of oxygen in the tissue

A

left

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36
Q

———- is formed via interaction of CO with nitric oxide (NO) release by platelets

A

Peroxynitrite

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37
Q

CO normal ranges and criticals

A

normal: 0-3%
smokers: 5-10%
critical: >60%

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38
Q

treatment of cases when COHb >20%

A

Hyperbaric oxygen therapy

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39
Q

Act by releasing monoamines from nerve terminals in the brain

A

amphetamines

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40
Q

effects of amphetamines

A
  • Locomotor stimulation
  • Euphoria and excitement
  • Anorexia
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41
Q

———- are a class of drugs whose effects mimic those of stimulated sympathetic nervous system.

A

Sympathomimetics
(amphetamines)

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42
Q

Class of drugs that form the largest group of hypnotics and sedatives

A

barbiturates

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43
Q

Reversibly depress the activity of all excitable tissues

A

barbiturates

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44
Q

Anti anxiety properties of ——– are inferior to those exerted by the ————–.

A

barbiturates
benzodiazepines

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45
Q

Hypnotic doses increase the total sleep time and alter the stages of sleep in a dose-dependent fashion

A

barbiturates

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46
Q

Can form alcohols, ketones, phenols, or carboxylic acids, all of which may appear in the urine

A

barbiturates

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47
Q

Represent the most widely prescribed drugs due to their principal pharmacological effects

A

benzos

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48
Q

Act selectively on GABA receptors, which mediate fast inhibitory synaptic transmission throughout the CNS

A

benzos

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49
Q

High lipid solubility causes them to accumulate gradually in body fat

A

benzos

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50
Q

Completely metabolized and are excreted as glucuronide conjugates in the urine

A

benzos

51
Q

Catalepsy: Retention of fixed unnatural postures

A

THC

52
Q

highly lipophilic and therefore are sequestered in body fat, and excretion continues for several days after a single dose

A

THC

53
Q

Pharmacological effects lie in its ability to inhibit catecholamine uptake by the noradrenaline and dopamine transporters.

A

cocaine

54
Q

Euphoria, garrulousness, increased motor activity, and a magnification of pleasure

A

cocaine

55
Q

Illegal use: Uses hydrochloride salt

A

cocaine

56
Q

Primary adverse effects include cardiac dysrhythmias and coronary or cerebral thrombosis.

A

cocaine

57
Q

Qualitative screening test in urine is designed to detect the metabolite benzoylecgonine.

A

cocaine

58
Q

A long-acting μ-receptor agonist

A

methadone

59
Q

Causes miosis or constriction of the pupils in most patients

A

methadone

60
Q

Widely used as a drug to treat morphine and diamorphine addicts.

A

methadone

61
Q

Applies to any substance, whether endogenous or synthetic, that produces morphine-like effects that are blocked by antagonists such as naloxone hydrochloride (Narcan)

A

opioid

62
Q

Synthetic, morphine-like drugs with nonpeptidic structures

A

opiate

63
Q

An extract of the poppy Papaver somniferum that has been used for centuries to produce euphoria, analgesia, sleep, and to prevent diarrhea

A

opium

64
Q

Federal DHHS guidelines and DOT regulation currently limit drug testing for opiates to…

A

heroin, morphine, and codeine

65
Q

In the clinical lab, Immunoassays for opiates are designed primarily to detect morphine and codeine at a cutoff concentration of —– ng/mL

A

300

66
Q

Treatment for opiate overdose may include administration of ———– by IV

A

naloxone

67
Q

Brand name Sernyl, street name “angel dust”

A

Phencyclidine/PCP

68
Q

Affect thought, perception, and mood without causing marked psychomotor stimulation or depression.

A

Phencyclidine/PCP

69
Q

Drugs with a chemical resemblance to known neurotransmitters (——–)

Drugs unrelated to monoamine neurotransmitters (———)

A

LSD
PCP

70
Q

Primary mechanism of action is to block the uptake of amines by nerve terminals for binding sites on the transport protein.

A

Tricyclic Antidepressants (TCA)

71
Q

Most ———– lead is absorbed, but only 20-70% ———- lead is absorbed

A

inhaled
ingested

72
Q

Adults retain <1%, where children <2 years old retain 30%

A

lead

73
Q

hemolytic anemia

A

Acute, high-level lead exposure

74
Q

hypochromic microcytic anemia

A

chronic lead exposure

75
Q

Current biomarker for assessment of lead exposure is…

A

venous whole blood lead with or without measured fluorinated ethylene propylene (FEP)

76
Q

ferrochelatase
ALA dehydratase

A

lead inhibition

77
Q

Competes with ethanol for alcohol dehydrogenase (ADH), and ethanol is used as an antidote.

A

methanol

78
Q

Methanol is metabolized by ADH to form ———— (instead of acetaldehyde with ethanol) which converts to ———–.

Causes severe metabolic acidosis.

A

formaldehyde
formic acid

79
Q

Methanol conversion not only takes place in the liver, but also the….

A

retina
blindness can occur

80
Q

Central scotoma (island-like blind spot), blurred vision, tunnel vision, or diplopia

A

methanol

81
Q

2 treatments for methanol poisoning

A

ethanol
hemodialysis

82
Q

Metabolized to glycoaldehyde, glycolic acid, glyoxylic acid, and ultimately oxalic acid.

A

ethylene glycol

83
Q

———- induces metabolic acidosis during ethylene glycol poisoning

———- leads to CaOx in urine

A

Glycolic acid
Oxalic acid

84
Q

3 stages of ethylene glycol poisoning

A
  1. neurologic
  2. cardiopulmonary
  3. renal (>24 hours)
85
Q

tx for ethylene glycol

A

ethanol or fomepizole
hemodialysis when severe

86
Q

Many ERs have a wood’s lamp that provides a long-wavelength UV radiation to detect ——————-

additive in radiator fluid

A

fluorescein

87
Q

Oxidized to a ketone (acetone) and no further

ketonemia without acidosis

A

isopropanol

88
Q

Tricyclic structure, with two benzene rings linked by sulfur and a nitrogen atom

Antipsychotics

A

phenothiazines

89
Q

Class of compounds referred to as anticholinesterase agents.

A

Organophosphate and Carbamate Compounds

90
Q

Used extensively in agricultural insecticides, in pesticides, and as potential chemical warfare “nerve gas.”

A

Organophosphate and Carbamate Compounds

91
Q

Testing is available to measure serum butyrylcholinesterase (pseudocholinesterase) activity to diagnose acute ingestion or monitoring chronic exposure

A

Organophosphate and Carbamate Compounds

92
Q

“Liquid ecstasy, liquid X, liquid XE, Georgia home boy, scoop, fantasy”

A

Gamma-hydroxybutyrate (GHB)

93
Q

Structurally similar to the inhibitory neurotransmitter γ-aminobutyric acid (GABA)

Cause deep, short-lived coma (1-4 hours long)

A

Gamma-hydroxybutyrate (GHB)

94
Q

Usually have spontaneous recovery with no recollection of taking drug due to anterograde amnesia

A

Gamma-hydroxybutyrate (GHB)

95
Q

Nonbarbiturate anesthetic compound structurally similar to PCP

A

ketamine

96
Q

Primarily affects the cerebral cortex and locus coeruleus

A

LSD

97
Q

Blood levels in the range of ng/dL or µg/kg

A

ultratrace metals

98
Q

Incorporated into antacids and astringents

A

aluminum

99
Q

↓ PTH and ↑ Aluminum

A

aluminum toxicity

100
Q

Treatment of Leishmaniasis
Treatment of Schistosomiasis

A

antimony

101
Q

Chronic workplace inhalation exposure leads to pneumoconiosis or pneumonitis (inflammation of the lungs)

A

antimony

102
Q

Arsenobetaine and arsenocholine

A

nontoxic forms of arsenic

103
Q

Monomethyl arsine (M M A)
Dimethyl Arsine (D M A)

A

arsenic metabolites

104
Q

British anti-Lewisite
Succimer

A

tx for arsenic toxicity

105
Q

A large percentage of absorbed ——— accumulates in the skeleton.

A

beryllium

106
Q

Develop chronic beryllium disease or berylliosis

A

beryllium toxicity; workers in industry

107
Q

The ——————- uses a sample of blood that measures beryllium sensitization, which represents an “allergic” reaction to beryllium.

A

beryllium lymphocyte proliferation test (BeLPT)

108
Q

The slow release of ————- from the metallothionein (MT)-complex in hepatic cells accounts for its long biological half-life of nearly 10 years

A

cadmium

109
Q

Chromium can enhance insulin receptors on cell membranes by binding with ——–

A

chromodulin

110
Q

An essential metal in vitamin B12

A

cobalt

111
Q

Associated with several metalloproteins and is essential for selective reduction-oxidation reactions

A

copper

112
Q

Inborn error of metabolism caused by a defective gene that regulates the metabolism of copper in the body

A

Menkes Syndrome

113
Q

An inherited autosomal recessive trait characterized by a defect in the metabolism of copper

A

Wilson disease

114
Q

s/s of Wilson disease

A
  • Kayser-Fleischer rings in the eyes (copper deposits)
  • Both plasma copper and ceruloplasmin will be decreased
  • Nonceruloplasmin-bound fraction of copper is increased, allowing copper to be deposited in the skin, eyes, brain, and kidneys
115
Q

Result of a gene defect that is characterized by an absence of ceruloplasmin

progressive neurodegenerative condition that results in tremors

A

Aceruloplasminemia

116
Q

Serves as an important constituent in several metalloenzymes that function to facilitate specific enzymatic reactions:

Superoxide dismutase
Pyruvate carboxylase
Arginase
Glycosyl transferases

A

manganese

117
Q

Enzyme that contain metal ions in their structures and serves as an essential component or cofactor

A

Metalloenzyme

118
Q

Chelation therapy with BAL or succimer, hemodialysis, and combinations of the 2 therapies

A

mercury poisoning tx

119
Q

Nonmetal thought to be closely associated with vitamin E in its functions.

A

Selenium

120
Q

Used in medicine as a bactericidal agent

Inserts itself into DNA structures, but doesn’t destroy the double helix

Inhibits fungal DNAse

A

silver

121
Q

Permanent bluish-gray discoloration of skin, mucous membranes, and nails because of silver deposits in those tissues.

A

argyria

122
Q

2nd to iron as the most abundant trace metal in the body

A

zinc

123
Q

Inhaling asbestos containing dust leads to deposition of asbestos fibers in the pulmonary alveoli. (silicon)

A

Asbestosis