Toxicology Flashcards
Concerned with the deleterious effects of these chemical agents on all living systems
TOXICOLOGY
Primarily concerned with adverse effects in humans resulting from exposure to drugs and other chemicals as well as the demonstration of safety or hazard associated with their use
TOXICOLOGY
deals with the chemicals found in the workplace.
OCCUPATIONAL TOXICOLOGY
define and carry out programs for the surveillance of exposed workers and the environment in which they work
OCCUPATIONAL TOXICOLOGY
deals with the potentially deleterious impact of chemicals, present as pollutants of the environment, on living organisms
ENVIRONEMENTAL TOXICOLOGY
concerned with the toxic effects of chemical and physical agents on populations and communities of living organisms within defined ecosystems
ECOTOXICOLOGY
includes the transfer pathways of those agents and their interactions with the environment.
ECOTOXICOLOGY
ability of a chemical agent to cause injury in a given situation or setting; the conditions of use and exposure are the primary considerations.
Hazard
often a description based on subjective estimates (subjective injury) rather than objective evaluation
Hazards
expected frequency of the occurrence of an undesirable effect arising from exposure to a chemical or physical agent
Risks
Estimation of risk makes use of ?
dose-response data
A single exposure—or multiple exposures occurring over a brief period from seconds to 1 or 2 days
Acute exposure
Multiple exposures continuing over a longer period of time
Chronic exposure
If the intake of a long-lasting contaminant by an organism exceeds the latter’s ability to metabolize or excrete the substance, the chemical accumulates within the tissues of the organism.
Bioaccumulation
Although the concentration of a contaminant may be virtually undetectable in water, it may be magnified hundreds or thousands of times as the contaminant passes up the food chain
Biomagnification
colorless, tasteless, odorless, and nonirritating gas, a byproduct of incomplete combustion
Carbon monoxide
Threshold limit value of Carbon monoxide
25 ppm
MOA of CO toxicity
- formation of Carboxyhemoglobin (220x Oxygen affinity to Hgb)
- interferes with the dissociation of oxygen to remaining oxyhemoglobin
Most affected organs of CO poisoning:
Heart and Brain
Treatment for CO poisoning
Hyperbaric O2 (2-3 atm)
colorless, irritant gas generated primarily by the combustion of sulfur-containing fossil fuels
Sulfur Dioxide
Threshold Limit Value of Sulfur dioxide
2 ppm
MOA of Sulfur Dioxide Poisoning:
- Mucus membrane irritant (sulfurous acid)
- causes bronchial constriction
- asthmatics are sensitive
clinical feature of severe exposure of Sulfur dioxide poisoning
Delayed-onset Pulmonary edema
a brownish irritant gas sometimes associated with fires
NITROGEN OXIDES
exposure of farmers to NO2 in the confines of a silo
Silo-Filler’s Disease
MOA of NO2 poisoning
- Relatively insoluble deep lung irritant capable of producing pulmonary edema
- primarily targets type 1 alveolar cells
Drug therapy for NO2 poisoning
bronchodilators, sedatives, and antibiotics
Threshold Limit Value of NO2
3 ppm
bluish irritant gas and an important absorbent of ultraviolet light
Ozone
Clinical Features of Ozone Poisoning
- upper respiratory tract irritation
- Pulmonary edema
Threshold Limit Value of Ozone
0.05 ppm
Air Pollutants
- CO
- SO2
- NO2
- O3
Solvents
- Halogenated Alipathic Hydrocarbons
- CCl4 [5ppm]
- CHCl3 [10 ppm]
- C2HCl3 (trichlorethylene) [50 ppm]
- C2Cl4 (tetrachlorethylene) [25 ppm]
- C2H3Cl3 (Trichlorethane or methyl chloroform) [350 ppm]
- Aromatic Hydrocarbons
- Benzene [0.5 ppm]
- Toluene [50 ppm]
- Xylene [100 ppm]
Clinical effects of Halogenated Aliphatic HC
central nervous system depression, liver injury, kidney injury, cardiotoxicity.
Clinical effects of Benzene
- Acute: epression of the central nervous system
- Chronic: bone marrow injury
- high level: Leukema
- low level: Myelotoxic
a central nervous system depressant and a skin and eye irritant. It is also fetotoxic.
Toluene (Methylbenzene)
4 major groups of pesticides
- Organochlorine
- Organophosphorous
- Carbamates
- Botanical
Organochlorine pesticides
- DDT (Chlorophenothane)
- Benzene hexachlorides (Lindane)
- Cyclodienes (Aldrin)
- Toxaphenes
MOA of Organochlorine Pesticides
- interfere with inactivation of the sodium channel
- cause rapid repetitive firing in most neuron
- enhances the excitability of neurons (CNS stimulation)
Organophosphorous pesticides
- Malathion
- Parathion (6)
- Methyl-parathion (5)
- Trichlorfon
- Diazinon
- Azinphos-methyl (5)
MOA of Organophosphorous pesticides
- inhibition of acetylcholinesterase through phosphorylation of the esteratic site
Treatment for Organophosphate poisoning
- Atropine Sulfate
- Pralidoxime
- Diacetyl monoxime
Carbamates pesticides
- Carbofuran
- Isolan
- Propoxur (Baygon)
- Pyrolan
- Zectran
- Aldicarb (6)
MOA of Carbamate poisoning
Inhibits acetylcholinesterase by carbamoylation of the esteratic site
Botanical Pesticides
- Nicotine
- Rotenone
- Pyrethrum
eacts with the acetylcholine receptor of the postsynaptic membrane (sympathetic and parasympathetic ganglia, neuromuscular junction) resulting in depolarization of the membrane
Nicotine
Symptoms of Rotenone Ingestion
gastrointestinal irritation, conjunctivitis, dermatitis, pharyngitis, and rhinitis
cause irritant asthma and, potentially, reactive airways dysfunction syndrome (RADS) and even anaphylaxis
Pyrethrum
for aircraft disinfection
Pyrethrum
major site of toxic action is the central nervous system; excitation, convulsions, and tetanic paralysis can occur
Pyrethrum
Treatment for Pyrethrum poisoning
- Ivermectin
- Pentobarbital
- Mephenesin
Herbicides
- Chlorophenoxy herbicides
- Bipyridyl herbicides
- Polychlorinated biphenyls
- Glyphosphate
toxicologic profile for chlorophenoxy hebicides is complicated by the presence of
chemical contaminants (dioxins)
is the most important agent of BIPYRIDYL HERBICIDES
Paraquat
Clinical features of Paraquats
lung edema, alveolitis, and progressive fibrosis
inhibits superoxide dismutase
Paraquats
Treatment for Paraquat poisoning
- Gastric lavage
- Cathartics
- Adsorbents
cooking oil contamination with PCB-containing transfer medium
Yusho disease
is now the most widely used herbicide in the world
Glyphosate (N-[phosphonomethyl] glycine