Principles of Pharmacology Flashcards
What makes a drug a ‘medicine’?
The intention of being given with therapeutic effect
What is a drug?
A chemical compound that produces biological effects
What is the term for drug substances that are already present in the body? Give two examples.
Endogenous
- Insulin
- Adrenaline
What is the 4-step pathway for discussing and studying the pharmacological effects of a drug?
- Pharmacodynamics
- Pharmacokinetics
- Clinical Uses
- Adverse effects and Contraindications
Define Pharmacodynamics
The drug’s mechanism of action upon the body
Define Pharmacokinetics. Include an explation of the ADME acronym
The body’s mechanism of action upon the drug.
Absorption-Distribution-Metabolism-Excretion.
What is the difference between Adverse Effects and Contraindications?
Adverse Effects are the non-theraputic, unwanted physiological effects of the drug.
Contraindications are the physiological/social/psychological factors in the patient that act as reasons NOT to prescribe the drug
What are the primary and secondary pharmacodynamic effects of Aspirin/NSAIDs?
- Analgesic
- 2 Anti-pyretic (anti-fever)
- 3 Anti-inflammatory
- Anti-platelet aggregation
Describe the pharmacodynamic mechanism of Aspirin
- Inhibits Cyclooxygenase (COX)
- COX catalyses Arachidonic Acid into Prostaglandings and Thromboxanes
Describe the 4 main physiological roles of Prostaglandins
- Sensitise pain nerve endings
- Dilates blood vessels (redness/inflammatory)
- Increases blood vessel permeability (swelling of Int. fluid comp)
- Induces fever
Describe the main physiological role of Thromboxanes
Induces increased platelet-aggregation
Drugs often act at ________ which are expressed only in selective tissues, and have the correct chemical structure to bind the drug.
Receptor Sites
Name three key effects of drug action as perpetuated by the ‘receptor site’ system.
Tissue Selectivity
Chemical Selectivity
Action Amplification (even at v. Small concentrations)
What name is given to the type of drug in which the drug binds to a receptor but DOES NOT induce a biological effect?
Antagonist
Define an ‘Agonist’ drug.
A drug which binds to a receptor to produce a biological cellular response
Draw a diagram to show the steps and relationship between drug ‘affinity’ and ‘efficacy’ in both agonists and antagonists.
Out of agonists and antagonists, which is the only one which can have a measured ‘efficacy’? And why?
Agonists. Because only agonists produced a direct biological response, whereas antagonists merely block receptor sites to inhibit the effect of endogenous hormones/enzymes
Define KA in the context of drug affinity
KA is known as the Equilibrium Constant. Specifically, it outlines the point at which exactly 50% of the receptor sites have been filled.
Draw a diagram to outline drug affinity. What type of pattern is formed by the typical data?
Define the EC50 of a drug. What quality does it measure?
The concentration at which 50% of the maximal biological response is achieved. Also designates the drug’s potency.
Draw a diagram to show why KA and EC50 are not equal, and explain why?
What do we call the ‘strength’ of a drug, as determined by a combination of its affinity and efficacy?
Potency
Define ‘ligand’
Defined as any molecule or atom that irreversibly binds to a receptor
What are ‘Partial Agonists’?
Partial agonists are ligands that bind to the agonist recognition site but trigger a response that is lower than that of a full agonist at the receptor
What type of antagonism involves antagonists competing with agonists for the same binding site?
Competitive antagonism
If KAnt < KA, which will occupy more receptor sites at equal concentrations?
Antagonist
Draw a diagram outlining ‘Surmountable’ antagonism. Why is there a parallel shift to the right in the present of antagonists?
Because the concentration of the agonists must be increased in a linear fashion to induce the same maximal biological response
Draw a diagram outlining ‘Insurmountable’ antagonism. Why is there a an antagonist-sensitive component? What are the differences between non-competitive and irreversible antagonism?
Name the four types of receptors, and give an example of an endogenous or given drug that acts there
Give an an overview of tissue selectivity
Give an overview of Chemical Selectivity
Give an overview of Intercellular communication
Give an overview of amplification
Broadly speaking, what are the four categories of receptor families?
Give three examples of intracellular messengers
cAMP (Cyclic AMP)
DAG (Diacylglycerol)
IP3 (Inositol 1,4,5-triphosphate)
Give an overview of Ligand gated receptor/channel complexes
Include an:
Example
Structure
Mechanism
Speed
Give an overview of G-coupled protein receptors.
Include an:
Example
Structure
Mechanism
Speed
Describe the process of intracellular communication initiated via G-protein coupled receptors
Draw the basic pathway function of GaS/GaI vs GaQ receptors and how they instigate intracellular communication
Give a diagrammatic outline of how Intracellular receptors work
Give an outline of how tyrosine kinase receptors work
