toxicology

?
  • Created by: Rscottqub
  • Created on: 05-01-20 14:48
toxicology
the science of poisons, the study of adverse effects of chemical,physical or bio agents on people, animals and the environment
1 of 68
all things are poisons
there is nothing without poisonous qualities - it is the dose and frequency which makes something toxic
2 of 68
all drugs have a
dose response curve
3 of 68
botox in the smallest conc can be
fatal
4 of 68
different drugs have different
potency's
5 of 68
types of sources of poison
1. physical sources, 2. biological sources 3. chemicals
6 of 68
physical sources
radiation- will damage cells
7 of 68
biological agents
ie bacteris, viruses, fungi attack and damage cells
8 of 68
chemicals
ie drugs, dyes - the biggest source of toxins
9 of 68
biological toxins
sub type of the bio agents - organism ( ie bacteria) itself doesn't cause damage but it secretes bio toxins which result in damage
10 of 68
toxicological profile
physio chem properties , route of exposure,
11 of 68
all drugs are toxic in ......
an OD
12 of 68
people vary in their
sensitivity to drugs
13 of 68
what is tested during animal testing?
multiple tests- different species, long term admin, post mortem examin, physio and bio monitoring
14 of 68
not all adverse effects that occur in animals
will occur in humans and vice versa
15 of 68
some side eff. are predictable due to
the drugs MOA
16 of 68
what is a dose
amount of substance administered at one time
17 of 68
drug dose depends on
number of doses, frequency of doses, treatment period, exposure site , sub properties
18 of 68
types of dose
administered dose, absorbed dose, target dose
19 of 68
administered dose
amount administered orally or by injection
20 of 68
absorbed dose
the amount of sub entering body via eyes, skin,lungs or GIT and was taken up by organs or particular tissues . AKA internal dose
21 of 68
target dose
amount at the site of action for the necessary period of time
22 of 68
side effect
drugs will produce many effects but only 1 is associated with the primary objective of therapy - all others are considered side effects
23 of 68
all side effects are bad
false - some are beneficial
24 of 68
toxic effect are always
undesirable
25 of 68
what sort of dose are we aiming for ?
most effective dose but minimally toxic - balancing act between effective dose and toxic dose
26 of 68
NOAEL
No observed adverse effect level- the highest dose with no adverse effects seen
27 of 68
LOAEL
lowesr observed adverse effects level - the lowest dose where first see toxic effects
28 of 68
which will always be lower NOAEL or LOAEL
NOAEL - will always be lower ***
29 of 68
types of toxicity
acute , sub chronic , chronic
30 of 68
acute
occurs almost immediately. usually a single dose or series of doses received in 24hr period
31 of 68
sub chronic
from repeated exposure for several weeks/months.
32 of 68
chronic
cumulative damage to particular organ system - takes months/years to be recognized as clinical disease
33 of 68
Classifying undesired effects
5 ways to classify side effects
34 of 68
1. local or systemic toxicity
local- site of 1st contact systemic - absorption and distribution of toxicant to distant site
35 of 68
2. REVERSIBLE or irreversible
Reversible - ie liver, kidney , skin - generally as long as you remove the toxin it can make a recovery. Liver can regen. itself
36 of 68
Irreversible
ie mutagens - perm damage to DNA , carcingogens - cause proliferation. Treatment here is to kill cells affected rather than treat them
37 of 68
Teratogen
drug which directly/indirectly causes structural changes in the the baby- ie thalidomide . NB most drugs are not teratogens
38 of 68
3, IMMEDIATE or Delayed toxicity
Immediate toxic eff. - occur quickly after single dose
39 of 68
delayed toxic effects
occur after a lapse of time
40 of 68
carcinogens example of
delayed - often 20-30 years before tumors are observed in humans
41 of 68
4. Allergic reactions (chemical allergy)
immune adverse reaction to a chemical. 1st time take something your allergic to - no effects - only on re exposure - adverse reaction
42 of 68
most reactions are
just minor skin eruptions - serious anaphalaxis is rare
43 of 68
5. Idiosyncratic reactions
not an allergic response - it is increased sensitivity . it is a genetically determined reactivity to a chemical
44 of 68
Bhopal tragedy
Dec 1984, 40 tons methyl ioscynate gas leaked from pesticide plant .0 .5 million exposed - 3800 killed instantly . 20k premature deaths in following decades, 100k chronically ill
45 of 68
Mechanisms of toxicity
exposure phase, toxixokinetic phase , toxicodynamic phase
46 of 68
exposure phase
magnitude of toxic effects depends on: form of exposure route of exposure, nature of contact, intentional or accidental, physical state of compound- ie more serious effects if inhaled - as by pass 1st PM
47 of 68
Toxicokinetic phase
ADME - A, conc, SA od exposure, D- transport proteins, barriers BBB, M- toxication E- kidney damage if excreted via kidneys?
48 of 68
Toxicodynamic phase
events following drug receptor interaction that will result in toxic effects-
49 of 68
what is toxicity
molecular reaction bet. sub and endogenous molecule
50 of 68
types of molecular reaction (ie from prev slide(
non covalent bonding (usually reversible) Covalent binding (practically irreversible - perm alters endogen. mol.) Hydrogen abstraction - free radical formation. Electron transfer (redox rxtions) Enzymatic reactions
51 of 68
cytotoxcity
causes injury to cells - Direct (primary) indirect (secondary)
52 of 68
Direct
occurs if toxic sub interacts with one/more of cells components
53 of 68
Indirect
results from disruption of microenvironment within cell- ie metabolism,cell activity
54 of 68
during cell injury what is altered
homeostatis - adaptive responses aim to balance distrubances to cell metabolism etc - if these fail - cell is irreverisbly damaged - cell death
55 of 68
Drug misuse poisoning deaths are mainly
accidental - most common - opiates
56 of 68
poisoning is
the 2nd most common method of suicide in the Uk. F>M
57 of 68
common suicide drug
paracetamol, propranolol - slow HR
58 of 68
toxicokinetics of propranolol (ADME)
A-rapid ab orally D- rapidly distributed - v lipophillic - into tissue including CNS. M- extensive hepatice met. E- 95-100% ingested dose excreted in urine . T0.5= 3-6hrs
59 of 68
toxicodynamics of propranolol
decreased HR and CO . Possible bronchospasm and hypoglycaemia. Blockade of Na channels - seizures, ventricular arrthymia
60 of 68
management of propranolol OD
keep airways clear for breathing. resuscitation with fluid therapy- iv atropine sulphate for bradycardia. iv glucagon- increase HR
61 of 68
CO poisoning
incomplete combustion of carbon based fuels . Route exposure - inhaltion.
62 of 68
toxicokinetics of CO poisoning
binds to Hb - reducing Hb O2 carrying capacity . Also inhibits mito respiration. both result in less o2 in the blood
63 of 68
initial CO poisoning symptoms
dizzy, nausea vomit, tiredness , confusion, stomach pain, shortness of breath
64 of 68
symptoms could develop to
impaired mental state , vertigo, tacycardia, seizures , loss of consciouness, chest pain/heartv attack
65 of 68
treatment
100% o2 if available- using tight fit mask. until COHb levels are less than 3% in non smokers 10% in smokers .
66 of 68
Half life of COHb when breathing air
320mins
67 of 68
when breathing 100% o2
80mins - O2 accelerates elimination of COHb Vs air
68 of 68

Other cards in this set

Card 2

Front

all things are poisons

Back

there is nothing without poisonous qualities - it is the dose and frequency which makes something toxic

Card 3

Front

all drugs have a

Back

Preview of the front of card 3

Card 4

Front

botox in the smallest conc can be

Back

Preview of the front of card 4

Card 5

Front

different drugs have different

Back

Preview of the front of card 5
View more cards

Comments

No comments have yet been made

Similar Pharmacy resources:

See all Pharmacy resources »See all toxicology resources »