Drug Interactions and Receptors Flashcards
What are the 3 main problems with drug interactions?
1) Polypharmacy
2) Ageing population
3) Increased OTC drug usage
What are 5 patient risk factors for drug interactions?
1) Old age
2) polypharmacy
3) Renal disease
4) Hepatic disease
5) Genetics
What are 3 drug risk factors for drug interactions?
1) Narrow therapeutic index
2) Saturable metabolism
3) Steep dose/response curve
What are 3 types of drug itneraction?
1) Synergy
2) Antagonism
3) Other
How might drug interactions affect drug metabolism?
IF CYP450 is induced/inhibited then metabolism of another drug could be affected
What do most drugs target?
Proteins
What are 4 receptors that drugs target?
1) GPCR (Muscarinic/B2)
2) Ligand gated ion channels (Nicotinic Ach receptor)
3) Kinase linked
4) Cytosolic/Nuclear linked (Steroid receptor)
What are the differences between agonist and antagonist?
Ag: Binds to receptor and activates it
Antag: Decrease agonist, with no effect on receptor
What shape does a log-dose response curve have?
Sigmoidal
What is the EC50 of a drug and what does it tell us?
Def: Potency of a drug
Tells: Concentration of a drug that gives half the maximal response
(The lower the EC50 the greater potency)
What does the Emax of a drug reveal?
The efficacy of a drug
How does an antagonist shift a drug dose curve?
Shifts the curve to the RHS making it become less potent
What is affinity?
How well a drug binds to a receptor
What is efficacy?
How well a ligand activates a receptor, (Induce confirmational change)
What will fewer drug receptors have on potency?
Shift the curve to RHS, so drug potency will be reduced
What is allosteric modulation?
Binds to a site on a different receptor, influencing role of an agonist
What is inverse agonism?
Where an agonist has a negative effect on a receptor
Does an antagonist show efficacy?
Antagonist has affinity but zero efficacy
What is tolerance?
Reduction in the effect of a drug overtime
What are the 2 types of inhibitor?
1) Irreversible: React with the enzyme and chemically change it
2) Reversible: Bind N-Cov and produce different types of inhibition
What are the differences between pharmacodynamics and kinetics?
1) Dynamics: How drugs affect the body
2) Kinetics: How does the body handle the drug (ADME)
What are the 4 components of pharmacokinetics?
1) Metabolism
2) Excretion
3) Absorption
4) Distribution
