Toxicology Flashcards
study of adverse effects of chemical, physical and biological agents
toxicology
ability of the substance to cause injury
toxicity
agent that is capable of producing deleterious effects in a biological system, seriously injuring function or producing death
poison
“ward” version of poison
toxicant
naturally occurring (plant/animal derived, endogenous to the organism)
toxins
synthetically manufactured poisons
xenobiotics
clinical state; overdose of drugs, medicaments, chemicals and biological substances
poisoning
mechanisms of actions of chemicals in their toxic states
toxicodynamics
adsorption, distribution, metabolism, excretion characteristics of substances in their toxic states
toxicokinetics
involves toxicity testing of
chemicals, providing information for safety evaluation,
regulatory requirements (for example: chemical profile,
activity, how substances behave in different media)
descriptive toxicology
concerns with identifying and
understanding mechanisms of action by which chemicals
exert toxic effects on living organisms, guide us on
treatment
Mechanistic Toxicology
involves in decisions,
guidelines, and policies, on the basis of data provided by
descriptive and mechanistic toxicology, whether a
chemical poses a sufficiently low risk to be marketed for
a stated purpose (for example: tolerability, special
licenses to prescribe)
regulatory toxicology
concerns with diseases caused by
or uniquely associated with toxic substances
Clinical Toxicology
Clinical Toxicology plus Forensic
Pathology – concerns primarily with the medicolegal
aspects of the harmful effects of chemicals on humans
and animals. Does not only deal with toxicological cases
where the patient is already dead. (for example: collect
specimen and date for evidence)
Forensic Toxicology
focuses on the impacts of
chemical pollutants in the environment on biological
organisms
Environmental toxicology
study of the adverse effects
of agents that may be encountered by workers during the
course of their employment
Occupational Toxicology
Factors affecting Responses to Toxic Agents
Agent
Envrionment
Individual Factors
potential that injury will occur in a given situation
Risk
intrinsic characteristic to cause harm to a
biological material
Toxicity
amount of chemical that is available for
absorption.
Exposure
explain R=TE
since toxicity of the substance is innate and constant, increase in exposure will cause increase in risk
examples of Factors under “AGENT”
Chemical and Physical Properties of Substances
- physical state
- solubility
- vapor pressure
- vapor density
- reactivity
Physical State of substance: indications
liquid and gas are more easily absorbed in systemic circulation; more toxic
Solubility of substance: indications
Lipophilic material & unionized
substances (easily absorbed)
»> more dangerous
Vapor pressure: indication
> =1 mmHg, rapid volitzation, can travel faster, more reach
Vapor density: indication
> 1 - heavier than air - toxic substance will sink
Reactivity: indications
Converted to a more toxic
metabolite/compound
Charged particles and reactive
oxygen species are more
deleterious.
Talks about the Exposure Situation
Environment
Factors under “ENVIRONMENT”
Duration
Frequency
Route
dosage
Types/variations of duration
Acute Exposure
Subacute Exposure
Subchronic Exposure
Chronic Exposure
exposure of substances with inhalational route
acute
exposure of substances with oral route (usually)
subacute
exposure which can result in cancer and transgenerational effects (i.e. endocrine)
chronic
frequency of exposure is critical to ____
concentration levels of the substance in
biological fluids at target sites
Order of effectiveness toxicity of different routes
Parenteral (Bioavailability= 100) > Inhalational >
Intraperitoneal > Intramuscular > Subcutaneous > Intradermal
> Oral and Dermal
most critical factor in determining whether the intrinsic
potential of a substance will be expressed
Dosage
example of agents which may trigger
transformation with one single exposure
Carcinogens, genotoxic agents
examples of drugs which may not establish a dose-response relationship
Endocrine disruptors
only a small amount (1 pg) of _____ can cause cancer
dioxin
Examples of Individual Factors
Age sex genetic background nutritional status general health status
paracetamol overdose leads to
liver problems
isoniazid overdose leads to
inhibition of GABA synthesis -> seizures and B6 deficiency
T/F The toxic action of a drug is an exaggeration of its therapeutic action
F; not necessarily;
Some chemicals do not just exaggerate their actions
in toxic states, they completely change their behavior
example of a toxicant which may exert several mechanisms of toxic
actions
lead
- > breaks down sulfhydryl molecules of myelin sheaths -> neuropathy
- > interferes with hemoglobin production by enzyme inhibition
