Toxicology Exam 1

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Toxicology
- basic science of poisons
- adverse effects of chemicals on biologic systems
Poison

any agent capable of producing injury or death when ingested or absorbed
Toxicologist

public health relevance of chemicals and chemical exposure
Types of Toxicology
- mechanistic toxicology
- regulatory toxicology
- descriptive toxicology
- specialized toxicology
Descriptive toxicoloty
- tells what damage a drug can produce
- ex. liver damage
Specialized toxicology is comprised of
- clinical toxicology
- forensic toxicology
Clinical toxicology
- drug interactions
- drug chemical interactions
Forensic toxicology
- over and under dosage
- poisoning
Origins of toxicology
- physics
- biochem
- physiology
- pharmacology
- biology
- medicine
Are all substances poisons?

yes
Largest organ of toxicology
- liver
- enlarged due to evolution
Delaney Clause
- make sure that drugs on the market are safe and efficatious
- thalidomide incident
Photomelia

complete absence of limbs
allergic reactions
- elicit immune response
- systemic
idiosyncratic reactions
- reactions to chemicals that the general population does not react to
- 5% or less of the population will react
Additive interaction of chemicals

3 + 2 = 5
Synergistic interaction of chemicals

3 + 2 = 20
Potentiation interaction of chemicals

non-toxic substance but when added with a toxic substance it becomes toxic
four levels of antagonism
- functional
- chemical
- dispositional
- receptor
Functional antagonism

change the physiology to counteract effects
Chemical antagonism/inactivation
- binding of substrate to the poison to render the toxic agent inactive
- chelating agents and metals
DIspositional antagonism
- ETOH, Methanol and Et. Glycol
- block Alcohol dehydrogenase to block metabolism of toxic agents
Receptor antagonism
- naloxone
- competitive antagonist competes for receptor binding
Routes and sites of exposure (4)
- GI
- lungs
- skin
- parenteral
vein that carries substance to the liver for 1st pass effect

portal vein
Splenic vein

carries blood to the kidney
Zero order kinetics
- rate remains constant and is independant of concentration
- biological systme is rate limiting
- t_1/2 increases with dose (false half life)
- alcohol
First order kinetics
- rate is directly proportional to the concentration
- chemical is rate limiting
- true t_1/2
- most chemicals handled like this
- upon saturation, may change to zero order

Author

Rx2013

59583

Card Set

Toxicology Exam 1

Description

General principles of toxicology

Updated

2011-01-13T16:29:41Z

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