Week 12 - Pharmacology: Intro to Pharmacodynamics Flashcards
What is a drug
A chemical substance of known structure, other than a nutrient or an essential dietary ingredient, which, when administered to a living organism, produces a biological effect
What are examples of drugs
Penicillin, Aspirin, Caffeine, St John’s wort, Flavonoids (green tea)
What is pharmacodynamics
the study of what the drugs does to the body
What are drug targets
Any binding site that interacts with a drug
Drug molecules have to interact with the target to have an effect
What do dose response curves show the relationship between
drug concentration and pharmacological response. (how much drug is required to produce the desired effect)
What is the threshold in a dose response curve
the concentration where effects start to occur
What is EC50 in a dose response curve
the concentration where half of the maximum effect occurs
What is the maximum effect on a dose response curve
the concentration where the full response occurs
What is efficacy
- the maximum effect that can be produced once binding has occurred. The higher
- The higher the maximum effect of the drug the higher the efficacy of the drug
What is potency
- The amount of drug needed to provide clinical effect
- If a small amount is required then the drug has a high potency (ideal)
- If a large amount is required then the drug has low potency
- Potency is influenced by both efficacy and affinity
What is affinity
- The amount of binding to receptor the drug does
- High affinity means that the drug is binding to more receptors at lower concentrations
- Low affinity means that the drug is binding less and or dissociates more easily from receptors
What type of drugs are receptor binding
- agonist
- antagonist
What is an agonist
Agonist mimic the effect of the ligand (such as neurotransmitters, hormones or other signaling molecules) by binding to the same receptor and producing a similar effect.
It enhances the receptor effect
These can have high affinity and high efficacy
E.g. Type 2 diabetes drug (GLP-1) which mimics insulin receptor to lower blood sugar levels
What are the 2 types of agonist drugs
- full agonist
- partial
What is a full agonist
agonist drug which can achieve maximal response (high efficacy)
What is a partial agonist
agonist drug which produces a submaximal response even with high concentration, low efficacy (will never achieve maximum effect)
What is an antagonist
Antagonist bind to specific receptors in the body without activating them, thereby blocking or inhibiting the action of the substrate that would normally activate the receptor.
e.g. Naloxone
What is a reversible antagonist
Doesn’t strongly bond to the receptor and can be overridden by a high concentration of agonist
What is a irreversible antagonist
Forms strong bond to the receptor and cannot be disrupted by an agonist
What type of drugs are enzyme binding
inhibitors
What type of drug are carrier proteins/molecules
Drugs which are carrier proteins/molecules act in a similar manner to enzymes and acts as an inhibitor.
E.g. GLUT-4 which lets glucose be taken up by cells or NA+/K+ pump which helps resets the charge of a cell in the production of active potential
What is Selectivity
The ability of a drug to interact preferentially with one type of receptor or target over others. A drug can be specific and only bind to certain or singular receptors, or a drug can be non-specific and bind to several types of receptors.
What is Specificity
Refers to the degree to which a drug interacts directly with its intended target and does not interact with other molecule before binding to the receptor
Explain how beta blockers showcase side effects of drugs
The B-adrenergic receptor increases the heart rate and has 2 subunits - B1 and B2
Some selective drugs only interact to subunit B1 e.g. dobutamine
Other non-selective drugs interact to both B1 and B2 subunits e.g. propranolol
The issue is that B2 receptors can also be found in other locations other than the hear such as the lungs, blood vessels, GI tract, bladder, uterus , liver. Hence in non-selective drugs effects can be seen on these organs, resulting in side effects such as breathing problems, constipation nausea, dizziness.
What are common local anesthetics
lidocaine and antiacne
What type of drug is local anesthetic
antagonic
How does local anesthetics work
- Local anesthetic works by blocking the generation and propagation of action potentials in neurons, by blocking the flow of Na+
- They bind to ion channels and block the flow of Na+
- By blocking sodium channels it prevents the transmission of nerve impulses along sensory nerves, and hence the sensation of pain is temporarily abolished
- They are unionized molecules
Local anesthetics targets what
voltage gated sodium channels - antagonist
Does local anesthetics work intracellularly or extracellularly
Intracellular
