Principles of Pharmacology Flashcards
What is pharmacodynamics?
How a drug exerts its effect on the body
List 4 classes of protein drug targets.
receptors
enzymes
ion channels
transport proteins
what type of drug target does aspirin work on?
mechanism of action?
enzyme
binds to COX
prevents production of prostaglandins
what type of drug target does local anaesthetic work on? mechanism of action?
ion channel
blocks Na+ channels
therefore nerve conduction
what type of drug target does prozac (antidepressant) work on? mechanism of action?
transport protein
blocks serotonin carrier proteins
prevents removal from the synapse
what type of drug target does nicotine work on? mechanism of action?
receptor
binds to/activates nicotinic acetylcholine receptor
Define selectivity.
specific to a particular drug target
Peroglide (used to treat Parkinson’s) can have what negative effects at high doses? why is this?
hallucinations
hypotension
drug becomes less selective
List examples of drug-receptor interactions.
electrostatic
hydrophobic
covalent bonds
stereospecific
drugs that bind and activate receptors are?
agonists
drugs that bind and block receptors are?
antagonists
The affinity of a drug determines?
strength of binding drug to receptor
The efficacy of a drug is?
ability of an individual drug molecule to produce an effect once bound to a receptor
What is potency?
concentration or dose of a drug required to produce a defined effect (usually 50% tissue response)
When determining dose what is more important: potency or dose?
potency
In pharmacokinetic terms, absorption can be defined as?
passage of a drug from the site of administration into the plasma
Define bioavailability.
the fraction of the initial dose that gains access to the systemic circulation
List forms of drug administration.
intravenous injection oral inhalational dermal (percutaneous) intranasal
What type of absorption helps insulin access the brain?
pinocytosis
How do most drugs move across membranes?
diffusing across lipid membranes or
via transport proteins
List factors that influence tissue distribution.
regional blood flow
plasma protein binding
capillary permeability
tissue localisation
the amount of drug that is bound to plasma proteins depends on what three factors?
free drug concentration
affinity for protein binding sites
plasma protein concentration
What is phase 1 and 2 of drug metabolism?
introduce reactive group to the drug
add conjugate to reactive group
List examples of drug excretion and elimination.
lungs
breast milk
kidney (urine)
liver (bile)
Define clearance.
measure of the ability of the body to eliminate a drug
Define elimination half- life.
length of time required for the concentration of a particular drug to decreasetohalf of itsstarting dose in the body
Define time to peak plasma levels.
time required for a drug to reach peak concentration in plasma
The faster the absorption rate, the _____ the time to peak plasma concentration.
lower
