Toxicology Flashcards
Poison
A substance that is toxic by nature, no matter how it gets in the body or how much is taken
What is a drug
A substance that has some therapeutic effect when given in the appropriate circumstances and in the proper dose
Bioavailability
The extent to which any drug is present in sufficient amounts to produce the desired result
Half-life
The point when the bioavailability of a given drug has decreased to 50%
Excretion
How the drug is removed from the body
Therapeutic index
Comparison of the therapeutically effective dose to the toxic dose of a pharmaceutical agent
LD50 (lethal dose)
The amount of the substance required (usually per body weight) to kill 50% or the test population. Expressed as mg/kg
Unintentional OD
-medication dosing errors
-young children putting toxic substances in their mouth
-environmental contact
-industrial hazards
Routes of exposure
-ingestion
-inhalation
-injection
-absorption
Poisoning by ingestion
-Immediate or delayed effects
-in most cases there is time to provide treatment before the poison is metabolized by the GI tract
-Activated charcoal
Inhaled toxins
-common workplace hazard
—reach the alveoli quickly, providing instant access to circulation
-hypoxia is a common consequence
Poisoning by injection
By-passes first pass metabolism
-immediate effects, no takesies backsies
Poisoning by absorption
Slow to enter the circulation
Common is cases of pesticides
What questions to ask the pt
-What did you take?
When was is taken?
How much was taken?
What else was taken?
Has the pt vomited?
Why was the substance taken?
What substances does activated charcoal not work on?
-Strong acids
-Strong bases
-Ethanol
-Ferrous sulphate
-Methanol
