clinical pharmacology and drug action bds2 Flashcards
what is a drug
a chemical substance other than food that when administered to a living organism produces a biological effect on the structure or function of the body
what are medicinal drugs
substances intended for the use of diagnosis, prevention and treatment of disease
what are non medicinal drugs also referred to as
recreational
what are non medicinal drugs
illegal substances such as cannabis, heroin and cocaine, as well as legal substances such as caffeine, nicotine and alcohol
what are the three classifications for drug effects
therapeutic
side
adverse
what is included under the therapeutic effects of drugs
intended/desired outcomes of drug administration
seen as beneficial
what are the features of drug side effects
these are unintended effects that are known and predictable
they are usually harmful or negative but can occasionally be beneficial
they do not hinder the primary effect of the drug
what are the features of adverse drug effects
these are undesirable and unpredictable
usually more severe and harmful compared to side effects and can hinder the treatment or cause complications
what are the main drug types used in dentistry
local anaesthetics
antimicrobials
anxiolytics
analgesics
brief description of LA in dentistry
lidocaine and articaine
used for pain prevention during procedures
brief description of antimicrobials in dentistry
treat and prevent infections
eg penicillin and fluconazole
brief description of anxiolytics in dentistry
reduce anxiety
diazepam and midazolam
describe analgesics in dentistry
paracetamol and ibuprofen, reduces post operative pain
what is pharmacodynamics
the effects of the drug on the body and mechanism of action
basically looking at what the drug does to the body
what is pharmacokinetics
term to describe the four stages of absorption, distribution, metabolism and excretion of drugs
basically looking at what the body does to the drug
what are the four stages to pharmacokinetics
absorption
distribution
metabolism
excretion
what can drugs do
- simulate normal body communications
- interrupt normal body communications
- act on non host organisms to aid body defences
what are the two methods of host communication
hormone messages which deliver general information to all tissues
neural messages which deliver targeted information to specific tissues
effect of thyroid hormone
regulate metabolism and growth
effect of insulin and glucagon
regulate blood sugar levels
effect of adrenal gland hormones
regulate stress response, blood pressure, immune system and other essential functions
effect of sex hormones
puberty, pregnancy, menstruation, sperm production, sex drive
why can high doses of one hormone mimic the effects of another
because the structure of different hormones can be very similar
effects of hyperthyroidism
rapid metabolism
high pulse rate
sweating and heat intolerance
anxiety and agitation
weight loss
effects of hypothyroidism
cold intolerance
coarse skin
memory loss
slow pulse
low metabolism
do drugs treating hypo/hyperthyroidism affect the thyroid gland
no
function of the autonomic nervous system
regulate involuntary body processes eg heart rate, digestion and breathing
what are the two components of the autonomic nervous system
sympathetic and parasympathetic
how does the sympathetic nervous system control heart rate
adrenergic stimulation to speed up the heart via beta adrenergic receptors
how does the parasympathetic nervous system control heart rate
slows the heart via cholinergic receptors
what are autonomic drugs
drugs that enhance or inhibit the function of the parasympathetic nervous system and parasympathetic nervous system
what are some examples of autonomic drugs
adrenaline
atenolol
pilocarpine
atropine
which autonomic drug is a beta agonist
adrenaline
which autonomic drug is a beta blocker
atenolol
which autonomic drug is a cholingeric agonist
pilocarpine
which autonomic drug is a cholinergic blocker
atropine
topical administration
drug applied to the tissue where it acts
drug applied to the whole organism
systemic administration
drug administered by injection
parenteral administration
drug applied to skin for absorption
transdermal administration
drug injected into the tissues of the skin
subcutaneous administration
drug injected into muscle
intramuscular administration
drug injected into vein
intravenous administration
drug applied to the mucosa for adsorption
transmucosal administration
what are the four main modes of action of drugs
activation or blocking of receptors
activating or blocking enzyme function
opening or blocking ion channels
facilitation or blocking transport systems
what can receptors be coupled to
ion channels
g proteins
enzymes
gene transcription
describe the interaction between receptors and ion channels
agonist stimulates the receptor
G protein interacts directly with and changes the open probability of the ion channel
describe the relationship between receptors and enzymes
agonist stimulates the receptor and the G protein activates or inhibits the enzyme that gives rise to second messengers
what is efficacy
how effective the drug is at producing a response from the receptor
how is drug efficacy determined
affinity and occupancy
what is drug affinity
how avidly the drug binds to the receptor
what is drug occupancy
how much time the drug spends on the receptor
what is the measure of drug affinity
Kd (dissociation constant)
describe Kd values in relation to affinity
low dissociation constant value means there is a high number of receptors occupied at a low drug concentration meaning there is high affinity
high dissociation constant shows that drugs and receptors are more weakly attracted to each other as there are less receptors occupied at the same drug concentration
inversely proportional values (low Kd means high affinity)
what is an agonist
a drug that binds to the receptors and initiates the same action that would be produced by the substance be it a hormone or a neurotransmitter which would normally bind to the receptor
what is a partial agonsit
this binds to the receptor but only partially to activate the receptor. there is less efficacy in comparison to an agonist meaning it produces less than the maximal effect
increased partial agonist concentration will improve efficacy for some but not for others
what is the difference between agonists and partial agonists
if the drug is an agonist, it binds to the receptor and causes 100% effect. if it is partial, it binds but only partially activates it, so the signal is less than 100%
what is an antagonist
drug that binds to but does not activate the receptor, therefore blocking the response
describe competitive antagonists
these bind to the same site on the receptor as an agonist therefore blocking the agonists action
describe non competitive antagonists
bind to a different site on the receptor from the agonist, called an allosteric site, which prevents activation of the receptor
describe reversible antagonists
these bind non covalently and can be displaced.
antagonist effects can be reduced by increases the concentration of the agonist such as atenolol
describe irreversible antagonists
these bind to tightly to the receptor that it cannot be displaced, therefore this reduces the available receptors for the agonist.
the antagnostic effect is insurmountable at any concentration of the agonist
how can drugs change enzyme action
by inhibition. the competitive substrate antagonism means the drug competes with the substrate to bind to the enzyme
non competitive substrate inhibition means the drug binds to different sites from the substrate, causing a conformational change in enzyme structure which in turn prevents substrate interaction
how can the ion channels be affected
cell electrical activity or ion influx
which two factors affect drug efficacy
occupancy and affinity
