1. Principle Targets Flashcards
(38 cards)
Why do dentists need to understand drugs?
- to use and prescribe ratioanlly
- dental patients may already be taking drugs
- be up to date with pharmacology and therapeutics
- principals stay the same when individuals come and go
What is pharmacology?
- what the drug does to the body
- what the body does to the drug
Define ‘pharmacodynamics’
the effects of a drug on the body
What falls into pharmacodynamics?
- molecular interactions by which drugs exert their effect (targets for drug action, how drugs act at target, how drug produces action)
- influence of drug conc on magnitude of response (graph representation, therapeutic vs toxic effects)
What does pharmacodynamics let us do?
- determine appropriate dose range for patients
- compare effectiveness and safety of one drug to another
Define ‘pharmacokinetics’
what the body does to a drug
4 divisions of pharmacokinetics
- absorption
- distribution
- metabolism
- excretion
What does pharmacokinetics let us do?
- design and optimise treatment regiments for people based on route of administration, frequency of administration and duration of treatment
If a woman is itchy and sneezing, you diagnose hayfever. What questions arise for pharmaco kinetics or dynamics?
for dynamics
- why is the drug called antihistamine, where in nose does it work and is the nose the sole location of action?
For kinetics
- taken as a tablet so how does it get to nose, if symptoms continue, why does she have to take another
Histamine is released from … when triggered by …
- mast cells
- allergy
Why do you need to take an antihistamine every day to maintain effects?
- absorbed and excreted through kidneys
- conc of antihistamine reduced until another tablet taken
2 sources of drugs
- naturally occurring
- synthetic
Explain naturally occurring sources of drugs
- previously main source (plants)
- imp source of new drugs like taxanes - anti cancer agents in yew tree bark
Explain synthetic sources of drugs
- current main source
- can be totally synthetic or identical to naturally derived compounds e.g insulin (identical) or codeine (derived)
Define ‘biologics’
- naturally derived (natural within body) but synthetic products (can be generated outside body) e.g growth hormones or antibodies
2 ways drugs can interact with targets
- on shape (lock and key)
- charge distribution (type of bonds holding drug to target)
List bonds from weakest to strongest
- van der Waal’s
- hydrogen bonds
- ionic interactions
- covalent bonds
Explain Van der Waal’s forces
- shifting electron density in a molecules results in generation of a transient pos or neg charge
- react with transient areas of opposite charge in other molecules
Explain hydrogen bonds
- hydrogen atoms bonded to oxygen or nitrogen become more positively polarised
- these bond with more negatively polarised atoms e.g oxygen
Explain ionic bonds
- atoms with an excess of electrons (negatively charged)
- attract to atoms with a deficiency of electrons (positively charged)
Explain covalent bonds
two bonding atoms share elctrons
4 considerations taken when looking at drugs binding with targets. Which are about shape and which about charge?
- hydrophobicity (how much it likes water)
- ionisation of drug (pKa)
(above at charge) - conformation of target
- stereochemistry of drug molecule
(above are shape)
Most drugs are weak …
bases or acids
Most drugs are weak bases or acids. What does this mean for them binding?
- exist in ionised form
- how charged they are affects target site binding
- some target sites only bind un-ionised molecules, some prefer ionised molecules
