Basic Principles of Pharmacology Flashcards
Define pharmacology
This is the study of substances that interact with living systems through chemical processes
What are the the 5 R of medication safety
Right
1. Dose
2. Time
3. Route
4. Patient
5. Drug
Define pharmacokinetics
This is the time course of the drug and its metabolites through the body
What are the 4 main principles of pharmacokinetics
- Absorption
- Distribution
- Metabolism
- Excretion
What is the clearance
This is a measure of the bodies ability to eliminate a drug
What is the volume of distribution
This is a measure of a drugs propensity to remain in the plasma or distribute into the tissue thus a drug with a high volume of distribution will leave the plasma and enter the extravascular compartment
What is the half life
This is the time taken for the body to reduce the conc. of a drug by half
Define the therapeutic window
This is the difference between the minimal toxic conc. and the maimal effective conc.
How long does it take to reach the steady state
5 half lives
What is a loading dose
A larger than maintenance dose that helps to reach the therapeutic window faster
Define absorption
This is how much of the administered drug reaches the systemic circulation
What is first pass metabolism
This is the portion of orally administered drug that is removed by the liver before it reaches the systemic circulation
What are P glycoprotein transporters
These are active transporters that efflux lipid soluable drugs that cross the cell membrane in the gut and blood tissue barriers
Which drugs are able to pass through the BBB
- Small lipid soluable drugs
- Drugs that are substrates of transporters
What is a prodrug
This is a drug that is inactive or less active as compared to its metabolite and so needs to be metabolised to exert its effect
What are the 2 main processes of drug metabolism
- Introduction or exposure of the functional group through a ROH rxn
- Polar conjugation: This is where a polar group is added to facilitate excretion
What is meant by first order kinetics of metabolism
This is where a constant proportion of the drug is removed per unit time e.g. 10% and so the rate of metabolism increases with increased conc.
What is zero order kinetics in drug metabolism
This is where a constant amount of drug is removed per unit time and so there is exponential increases in drug conc. as a fixed amount is removed
What is meant by inhibition and induction
Inhibition: This is where a drug binds to an enzyme causing it to stop functioning thus increasing the conc. of drug in circulation as it is not removed
What is meant by induction
This is where there is increased expression of the genes that regulate enzymes and so there is an increase in the conc. of the enzyme causing faster removal of a drug
Who are the special populations in prescribing drugs
Liver and renal disease
Elderly and children
Pregnant and lactating
Porphyria
Define pharmacodynamics
This the study of the biochemical and physiological effects of the drugs
What is the ED50
This is the dose that elicits an effective response in 50% of individual
What is the LD50
This is the lethal dose in 50% of individuals
What is meant by potency
The amount of drug that is necessary to achieve a certain effect
What is the efficacy
This is the maximum possible effect of the drug
What is an agonist
This is a drug that binds to and activates that receptor
What is an antagonist
This a molecule that binds to a receptor and in doing so prevents other molecules from binding
What is the difference between a full and a partial agonist
A full agonist is a agonist that once it occupies the reseptor it initiated the full physiological effect and a partial produces a submaximal response
What are the 4 main types of antagonists
- Pharmacological antagonist: This is when the antagonist interferes directly with the receptor
- Physiological: 2 drugs act in opposing physiological effects
- Chemical: This is were 2 drugs in solution react with one another to neutralize one another
- Physical: They act through physical properties, such as solubility, adsorption, or distribution, rather than molecular interactions with receptors or enzymes e.g. charcoal
What is meant by tolerance
This is where larger doses are needed to experience the same effects
What are the 3 main mechanisms of tolerance
- Pharmacokinetic clearance: This is where there is increased clearance induced by repeated doses
- Pharmacodynamic clearance: This is where there is a change to the number of receptors or their function due to repeated exposure to the drug
- Behavioral tolerance: This is learned behavior that leads to diminished effects of the drugs
