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Flashcards in Pharmacodynamics Deck (36)
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1
Q

What is pharmacodynamics?

A

Study of action of drugs on the body

2
Q

What is pharmacokinetics?

A

Study of what the body does to the drug

3
Q

What is the generic name of a drug?

A

Non-proprietary name that each chemical can be given

4
Q

What is the trade name of a drug?

A

Proprietary name, owned by company

5
Q

Targets of drug action

A

Proteins, DNA, lipids

6
Q

What do inotropic receptors do?

A

Facilitate movement of ions across membranes

Require ligand binding - transient interaction

7
Q

Characteristics of ionotropic receptors

A
  • Require ligand binding - transient interaction (binding and dissociation happens rapidly)
  • Hyperpolarization or depolarization of cell
  • Typically penatameric
  • Pore in centre allows ions to flow
  • Signalling time is very fast - milliseconds
8
Q

Characteristics of G-protein coupled receptors

A
  • Largest family
  • Metabotropic receptors
  • 7 transmembrane domains
  • N-terminal domain is where drug binds
  • C terminal where G protein signaling takes place
  • Activating protein can influence ion channel activity or activate second messenger cascade
  • Ion channel excitability
  • G alpha s and G alpha I act via same secondary messenger
  • AC = adenylate cyclase, which catalyses of ATP to cAMP which influences PKA
  • G alpha I inhibits adenylate cyclase - negative effect cAMP and PKA
  • G alpha q activates phospholipase C which catalyses PIP2 to DAG and IP3
  • DAG and IP3 influence PKC
  • IP3 is calcium regulator
9
Q

How do kinase linked receptors work?

A
  • Single membrane spanning domain
  • Dimerization when drug binds
  • When drug binds, autophosphorylation of tyrosine kinase domain
  • Dimerization attracts intercellular proteins to express SH2 domain to activate targets, most common target is Ras/Raf/MAPK or Jak/Stat pathway
10
Q

Characteristics of nuclear receptors

A
  • Nuclear or cytosolic
  • Ligands lipid soluble
  • Act as transcription factors
  • Take hours
  • e.g. oestrogen receptor
  • Mainly steroids or hormones
  • Receptor activated when ligand binds
  • Nuclear receptors can increase or decrease gene expression
11
Q

What is drug specificity?

A

Binds selectively to particular receptor types

12
Q

What do agonists do?

A

Activate receptors

13
Q

What do antagonists do?

A

Block receptors, often inhibit endogenous agonist action

14
Q

What is the binding affinity?

A

How well does the drug bind to the receptor

15
Q

What is efficacy?

A

Ability of drug to bring about full response

16
Q

What is a full agonist?

A

Elicit 100% of endogenous agonist

17
Q

What is a partial agonist?

A

Elicits <100% effect

18
Q

What is a super agonist?

A

> 100% of endogenous effect

19
Q

What is an inverse agonist?

A

Reduce basal receptor activity

20
Q

What is potency?

A

Agonist drug potency is a product of affinity and efficacy

21
Q

What is an equipotent molar ratio?

A

Picking a threshold and observing concentration required to get that response

22
Q

Why don’t antagonists activate receptors?

A

They have zero efficacy

23
Q

What are receptor antagonists?

A

Reversible or irreversible - competitive (reversible) but can be competitive or uncompetitive

24
Q

What are non-receptor antagonists?

A

Chemical, physiological (produce opposite effect of agonist, e.g. insulin and glucagon) and pharmacokinetic (influencing action of one drug by modifying its pharmacokinetic profile)

25
Q

What are uncompetitive antagonists?

A

Endogenous compound binds, allowing antagonist to bind at alternative site

26
Q

What is an irreversible agonist?

A

Occupy and bind to receptors which reduces available receptors for agonists to bind - no response in extreme

27
Q

When will full agonists bring about maximum effect?

A

Binding to 20% of receptors

28
Q

What is EC50?

A

Dissociation constant for drug

29
Q

What is pharmacogemonics?

A

Genetic variability in the way drugs behave in the body

30
Q

What is pharmacokinetics?

A

Enzyme polymorphism

31
Q

What is desensitization?

A

A drug’s effectiveness may decrease rapidly when given repeatedly or continuously

32
Q

What is tolerance?

A

Decrease in a drug’s effectiveness over days or weeks

33
Q

What is resistance?

A

Adaptive change = less effective = enhanced or decreased drug metabolism,

34
Q

Drug factors affecting efficacy of drug

A

Pharmacokinetics and pharmacodynamics

35
Q

What is PCA?

A

Patient regulates dosing and becomes excessive if too drowsy
Dose sizes and lockout intervals introduced to ensure time allowed for drug to work

36
Q

Why might the outcome of a drug not be measured easily?

A
  • Long delay in seeing result
  • Multi-factorial condition
  • Examples: immunizing against disease, preventing ischemic heart disease, weight loss therapy