Toxicology Flashcards
What is the basic definition of toxicology?
The study of adverse effects of chemicals or physical agents on living organism
The science of poisons
Toxicology looks at the way…
Chemical interact with living beings and what changes they may cause or bring about
Changes due to toxic conditions may range from;
Immediate and life threatening
Subtle changes that may not be recognized for month, years, or never
What are some bodily levels toxic effects can occur in?
Biochemical, cellular and the whole organism
What is a xenobiotic?
Any foreign substance in the body
Can produce toxic or beneficial results
What makes something poisonous?
The dose
What is a toxicant?
substance that produced biological effects
May be beneficial or adverse, chemical or physical, acute or chronic
What is a toxin?
Specific proteins produced by living organisms
Most can cause immediate effects
What are poisons?
Toxicants that cause immediate death or illness when given in very small doses
What is a toxic agent?
Anything that can produce an adverse biological effects, but does not include agents produced by biological agents
What is a specific organ toxin?
Agents which act on specific organs
What is a systemic toxin?
Affects entire body
What is an organic toxin?
Chemical derived from living organisms
What are inorganic toxins?
Chemical not derived from living organisms
What is the definition of a dose?
The amount of substance administered at one time
What is an administered dose?
Quantity administered
What is an absorbed does?
Amount that actual enters the body
What is the total dose?
Sum of all administered doses
What does fractionating a dose do?
Decreases the probability of toxicity
What is the environmental unit?
The amount of a xenobiotic in a unit of the media
What is dose-response?
How much of a does is needed to an effect to take place
What is the threshold effect?
Establish the lowest dose where an effect occurs
Describe the dose response for individual and for a population;
Wide variance for individual
Narrow range of response in population
What is the top threshold for dose-response?
The level of toxicant at which the body can no longer detoxify itself
How can damage occur in a toxic event?
Cell replacement (fibrosis) Damage to enzme system Disruption of protein synth Production of reactive cell chemical DNA damage
How can xenobiotics have an indirect effect on toxicity?
Modification of essential biochemical functions
Interference with nutrition
Alteration of physiological function
What factors influence toxicity?
Chemical activity Dosage Route of exposure Species Excretion Age Metabolism Sex Body distribution Absorption abnormalities Presence of other chemicals Form of substance Innate chemical activity of the substance
What is one of the largest factors in toxicity?
Metabolism
- Detoxification: less toxic
- Bioactivation: more toxin
If a toxin is lipid soluble what does its distribution look like?
Wide
What are major avenues or toxin spread?
Blood and lymph
What is the significance of the exposure route of a toxin?
Some substances are more toxin by one route than another
What is the general rule for toxin route exposure?
Ingested chemicals go to liver and get detoxified
Inhaled chemicals go straight to the blood stream and distribute before getting to the liver
Site and range of excretion for toxin follow this pattern in general;
Kidney > GI tract > lungs
What does it mean when a chemical interaction is additive (additivity)?
A combination of two or more chemical is the sum of the expected individual response (most common)
What does it mean when a chemical interaction has antagonism?
Physiological: effect of one drug can be lessened or reversed by another
Chemical: the effect of one can be reduced by another (binding)
Disposition: one is absorbed by another (charcoal)
Receptor: one displaces another from receptor site
When is a chemical interaction has potentiation what does that mean?
One chemical without a specific effect makes another toxic
carbon tetrachloride + alcohol
What does it mean when a chemical interaction is synergistic?
One chemical may drastically inc the effect of another
cigarette smoke and radon
Why are federal agencies involved in toxicity testing?
Because there have been really horrible past disasters (especially with birth defects)
What are the federal agencies that are involved in toxicity testing?
FDA, EPA, CPSC and OSHA
What are the four steps of risk assessment of toxins?
- Hazard identification (characterization of toxic effects)
- Dose-response assessment (relationship of doses to adverse effects)
- Exposure assessment (estimate intensity, duration and frequency of exposure)
- Risk characterization (estimate of effect under various condition of exposure)
What are the three methods to toxicity testing?
- Study and observe during normal or accidental exposures
- Experimental animal studies
- Cellular studies
What are some common adverse drug reactions (ADR)?
Overdose of BP meds
ASA (anti-inflam)
Antihistamine
What are some cause effects of some med?
Fetal abnormalities
Stroke and MI
Insomina
Spontaneous achilles tendon rupture
What is an idosyncratic reaction?
Unpredictable, unexpected and scary reaction
