22) Toxic substances Flashcards
(123 cards)
1
Q
father of modern toxicology
A
Paracelsus
2
Q
positive screens require drug confirmation method with…
A
Definitive or reference method (GC-MS or LC-MS)
3
Q
2 steps of toxic drug test
A
- screening test; qualitative
- confirmatory test; quantitative
4
Q
a cutoff value is ———- than the detection limit, but —— enough to detect drug use within a reasonable time frame
A
higher
low
5
Q
————– are not always specific for the drug tested.
A
Immunoassays
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
7
Q
3 types of invalid urine specimens
A
- adulteration
- dilution
- substitution
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
9
Q
Creatinine and specific gravity values that are lower than expected for human urine
A
dilute urine
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
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
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
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
14
Q
urine adulteration test strip reactions
A
- Creatinine
- nitrite
- glutaraldehyde
- pH
- specific gravity
- bleach
- pyridinium chlorochromate
- oxidants
15
Q
Intect® 7
AdultaCheck®
Alere Toxicology PLC
A
urine adulteration test strips
16
Q
3 major effects of acetaminophen
A
- anti-inflammatory
- analgesic
- antipyretic
17
Q
Toxic doses, described as 2-3 times the maximum therapeutic dose, cause a serious and potentially fatal hepatotoxicity.
A
acetaminophen
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.
19
Q
Blood samples should be obtained after 4 hours to ensure absorption is complete
A
acetaminophen
20
Q
Not useful if the time of ingestion is unknown or unreliable
A
acetaminophen levels
21
Q
Most commonly consumed drug in the world
A
aspirin
22
Q
indications for aspirin use
A
- Cardiovascular disorders
- Colonic and rectal cancer
- Alzheimer’s disease
- Radiation-induced diarrhea
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
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)
25
Causes several metabolic changes in the body (3 types of acid-base disorder)
salicylate poisoning
26
3 ways aspirin can cause acid-base disturbances
1. resp alkalosis; hyperventilation
2. resp acidosis; respiratory depression, decreased serum bicarb
3. metabolic acidosis; accumulation of pyruvic acid, lactic acid, acetoacetic acid
27
Excessive elevation of body temperature >106.7°F
hyperpyrexia associated with aspirin poisoning
28
Can increase the effect of warfarin by displacing it from plasma proteins in addition to its effect on platelets
aspirin
29
Trinder reaction
aspirin
30
90% metabolized, 5-10% excreted unchanged in expired air and urine
ethanol
31
Metabolism of ethanol in the liver involves successive oxidations:
* 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
32
can barely walk, vomiting, possibility of LOC
0.20 - 0.249%
33
alcohol poisoning
0.25 - 0.399%
34
onset of coma, death with alcohol
>0.4%
35
The effect of CO on the oxygen dissociation curve is a shift to the -------, which decreases the release of oxygen in the tissue
left
36
---------- is formed via interaction of CO with nitric oxide (NO) release by platelets
Peroxynitrite
37
CO normal ranges and criticals
normal: 0-3%
smokers: 5-10%
critical: >60%
38
treatment of cases when COHb >20%
Hyperbaric oxygen therapy
39
Act by releasing monoamines from nerve terminals in the brain
amphetamines
40
effects of amphetamines
* Locomotor stimulation
* Euphoria and excitement
* Anorexia
41
---------- are a class of drugs whose effects mimic those of stimulated sympathetic nervous system.
Sympathomimetics
(amphetamines)
42
Class of drugs that form the largest group of hypnotics and sedatives
barbiturates
43
Reversibly depress the activity of all excitable tissues
barbiturates
44
Anti anxiety properties of -------- are inferior to those exerted by the --------------.
barbiturates
benzodiazepines
45
Hypnotic doses increase the total sleep time and alter the stages of sleep in a dose-dependent fashion
barbiturates
46
Can form alcohols, ketones, phenols, or carboxylic acids, all of which may appear in the urine
barbiturates
47
Represent the most widely prescribed drugs due to their principal pharmacological effects
benzos
48
Act selectively on GABA receptors, which mediate fast inhibitory synaptic transmission throughout the CNS
benzos
49
High lipid solubility causes them to accumulate gradually in body fat
benzos
50
Completely metabolized and are excreted as **glucuronide** conjugates in the urine
benzos
51
Catalepsy: Retention of fixed unnatural postures
THC
52
highly lipophilic and therefore are sequestered in body fat, and excretion continues for several days after a single dose
THC
53
Pharmacological effects lie in its ability to inhibit catecholamine uptake by the noradrenaline and dopamine transporters.
cocaine
54
Euphoria, garrulousness, increased motor activity, and a magnification of pleasure
cocaine
55
Illegal use: Uses hydrochloride salt
cocaine
56
Primary adverse effects include cardiac dysrhythmias and coronary or cerebral thrombosis.
cocaine
57
Qualitative screening test in urine is designed to detect the metabolite **benzoylecgonine**.
cocaine
58
A long-acting μ-receptor agonist
methadone
59
Causes miosis or constriction of the pupils in most patients
methadone
60
Widely used as a drug to treat morphine and diamorphine addicts.
methadone
61
Applies to any substance, whether endogenous or synthetic, that produces morphine-like effects that are blocked by antagonists such as naloxone hydrochloride (Narcan)
opioid
62
Synthetic, morphine-like drugs with nonpeptidic structures
opiate
63
An extract of the poppy Papaver somniferum that has been used for centuries to produce euphoria, analgesia, sleep, and to prevent diarrhea
opium
64
Federal DHHS guidelines and DOT regulation currently limit drug testing for opiates to...
heroin, morphine, and codeine
65
In the clinical lab, Immunoassays for opiates are designed primarily to detect morphine and codeine at a cutoff concentration of ----- ng/mL
300
66
Treatment for opiate overdose may include administration of ----------- by IV
naloxone
67
Brand name Sernyl, street name “angel dust”
Phencyclidine/PCP
68
Affect thought, perception, and mood without causing marked psychomotor stimulation or depression.
Phencyclidine/PCP
69
Drugs with a chemical resemblance to known neurotransmitters (--------)
Drugs unrelated to monoamine neurotransmitters (---------)
LSD
PCP
70
Primary mechanism of action is to block the uptake of amines by nerve terminals for binding sites on the transport protein.
Tricyclic Antidepressants (TCA)
71
Most ----------- lead is absorbed, but only 20-70% ---------- lead is absorbed
inhaled
ingested
72
Adults retain <1%, where children <2 years old retain 30%
lead
73
hemolytic anemia
Acute, high-level lead exposure
74
hypochromic microcytic anemia
chronic lead exposure
75
Current biomarker for assessment of lead exposure is...
venous whole blood lead with or without measured fluorinated ethylene propylene (FEP)
76
ferrochelatase
ALA dehydratase
lead inhibition
77
Competes with ethanol for alcohol dehydrogenase (ADH), and **ethanol** is used as an antidote.
methanol
78
Methanol is metabolized by ADH to form ------------ (instead of acetaldehyde with ethanol) which converts to -----------.
Causes severe metabolic acidosis.
formaldehyde
formic acid
79
Methanol conversion not only takes place in the liver, but also the....
retina
blindness can occur
80
Central scotoma (island-like blind spot), blurred vision, tunnel vision, or diplopia
methanol
81
2 treatments for methanol poisoning
ethanol
hemodialysis
82
Metabolized to glycoaldehyde, glycolic acid, glyoxylic acid, and ultimately oxalic acid.
ethylene glycol
83
---------- induces metabolic acidosis during ethylene glycol poisoning
---------- leads to CaOx in urine
Glycolic acid
Oxalic acid
84
3 stages of ethylene glycol poisoning
1. neurologic
2. cardiopulmonary
3. renal (>24 hours)
85
tx for ethylene glycol
ethanol or fomepizole
hemodialysis when severe
86
Many ERs have a wood’s lamp that provides a long-wavelength UV radiation to detect -------------------
additive in radiator fluid
fluorescein
87
Oxidized to a ketone (acetone) and no further
ketonemia without acidosis
isopropanol
88
Tricyclic structure, with two benzene rings linked by sulfur and a nitrogen atom
Antipsychotics
phenothiazines
89
Class of compounds referred to as anticholinesterase agents.
Organophosphate and Carbamate Compounds
90
Used extensively in agricultural insecticides, in pesticides, and as potential chemical warfare “nerve gas.”
Organophosphate and Carbamate Compounds
91
Testing is available to measure serum **butyrylcholinesterase** (**pseudocholinesterase**) activity to diagnose acute ingestion or monitoring chronic exposure
Organophosphate and Carbamate Compounds
92
“Liquid ecstasy, liquid X, liquid XE, Georgia home boy, scoop, fantasy”
Gamma-hydroxybutyrate (GHB)
93
Structurally similar to the inhibitory neurotransmitter γ-aminobutyric acid (GABA)
Cause deep, short-lived coma (1-4 hours long)
Gamma-hydroxybutyrate (GHB)
94
Usually have spontaneous recovery with no recollection of taking drug due to anterograde amnesia
Gamma-hydroxybutyrate (GHB)
95
Nonbarbiturate anesthetic compound structurally similar to PCP
ketamine
96
Primarily affects the cerebral cortex and locus coeruleus
LSD
97
Blood levels in the range of ng/dL or µg/kg
ultratrace metals
98
Incorporated into antacids and astringents
aluminum
99
↓ PTH and ↑ Aluminum
aluminum toxicity
100
Treatment of Leishmaniasis
Treatment of Schistosomiasis
antimony
101
Chronic workplace inhalation exposure leads to pneumoconiosis or pneumonitis (inflammation of the lungs)
antimony
102
Arsenobetaine and arsenocholine
nontoxic forms of arsenic
103
Monomethyl arsine (M M A)
Dimethyl Arsine (D M A)
arsenic metabolites
104
British anti-Lewisite
Succimer
tx for arsenic toxicity
105
A large percentage of absorbed --------- accumulates in the skeleton.
beryllium
106
Develop chronic beryllium disease or berylliosis
beryllium toxicity; workers in industry
107
The ------------------- uses a sample of blood that measures beryllium sensitization, which represents an “allergic” reaction to beryllium.
beryllium lymphocyte proliferation test (BeLPT)
108
The slow release of ------------- from the metallothionein (MT)-complex in hepatic cells accounts for its long biological half-life of nearly 10 years
cadmium
109
Chromium can enhance **insulin receptors** on cell membranes by binding with --------
chromodulin
110
An essential metal in vitamin B12
cobalt
111
Associated with several metalloproteins and is essential for selective reduction-oxidation reactions
copper
112
Inborn error of metabolism caused by a defective gene that regulates the metabolism of copper in the body
Menkes Syndrome
113
An inherited autosomal recessive trait characterized by a defect in the metabolism of copper
Wilson disease
114
s/s of Wilson disease
* **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
Result of a gene defect that is characterized by an absence of ceruloplasmin
progressive neurodegenerative condition that results in tremors
Aceruloplasminemia
116
Serves as an important constituent in several metalloenzymes that function to facilitate specific enzymatic reactions:
Superoxide dismutase
Pyruvate carboxylase
Arginase
Glycosyl transferases
manganese
117
Enzyme that contain metal ions in their structures and serves as an essential component or cofactor
Metalloenzyme
118
Chelation therapy with BAL or succimer, hemodialysis, and combinations of the 2 therapies
mercury poisoning tx
119
Nonmetal thought to be closely associated with vitamin E in its functions.
Selenium
120
Used in medicine as a bactericidal agent
Inserts itself into DNA structures, but doesn’t destroy the double helix
Inhibits fungal DNAse
silver
121
Permanent bluish-gray discoloration of skin, mucous membranes, and nails because of **silver** deposits in those tissues.
argyria
122
2nd to iron as the most abundant trace metal in the body
zinc
123
Inhaling asbestos containing dust leads to deposition of asbestos fibers in the pulmonary alveoli. (silicon)
Asbestosis
