intro to pharmacology Flashcards

1
Q

what is pharmacy?

A

the handling of drugs

- preparing, presenting and dispensing

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2
Q

what is pharmacology/toxicology?

A

science of drugs

  • drug design and synth
  • research into effects and mechanisms of drugs
  • absorption, metabolism and excretion of drugs
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3
Q

what is therapeutics?

A

the medical use of drugs (treatment of diseases and their symptoms)

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4
Q

how do drugs work?

A

most drugs at on normal cells (affect normal cell function)
- chemicals which bind to molecules in cells (usually proteins) and in doing so mimic (agonists) or block (antagonists) the action of endogenous molecules or processes

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5
Q

what are chemotherapeutic drugs?

A

agents that act against infectious micro organisms or cancer cells by exploiting biochemical differences between host and target cell

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6
Q

what are chemotherapeutic drugs used for?

A

treat infections and cancers - work less well on cancer as the cells are similar to normal cells
- drugs can be chemically identical or similar to an endogenous (growing from within) molecule of chemically distinct from any known endogenous molecule

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7
Q

where are binding sites for drugs found?

A

on enzymes, carrier molecules, ion channels and receptors

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8
Q

what are receptors

A

proteins, generally in the cell membrane, designed to recognise a messenger of great specificity at a specific recognition site (lock and key)

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9
Q

what happens when a drug binds to a receptor?

A

once binding site is occupied the receptor undergoes a conformational change and the signalling cascade is initiated, changing the function of the cell

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10
Q

what is the affinity of a drug KD for its receptor?

A

the conc of drug required to occupy 50% of the receptors at eqm

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11
Q

what is affinity?

A

how tightly the drug will bind to the receptor’s specific recognition sites

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12
Q

what effect does high affinity have on KD?

A

low KD - little drug needed to half-occupy receptors

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13
Q

what is efficacy?

A

ability to activate the receptor so a response is produced (likelihood of the conformational change which leads to signalling cascade)

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14
Q

what are agonists?

A

drugs that activate receptors

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15
Q

what are antagonists?

A

drugs that bind to receptors but do not activate them

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16
Q

what is the dose - response curve and what is its shape?

A

a plot of proportion of receptors occupied [P] against drug concentration [D]
rectangular hyperbole

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17
Q

what is the shape of log[dose]-response curve

A

symmetrical sigmoid

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18
Q

why may a drug have high potency?

A

high affinity to receptor, high efficacy or low metabolic breakdown in the body

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19
Q

what are the properties of an agonist?

A

high affinity and efficacy

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20
Q

what are the properties of an antagonist?

A

high affinity but low efficacy

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21
Q

what do reversible competitive antagonists do?

A

produces a shift right of the agonist dose-response curve as it competes for the binding sites with the agonist

  • size of right shift is dependent on the conc of antagonist
  • if enough agonist is made then it will overcome the antagonist
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22
Q

what do irreversible competitive antagonists do?

A

produce a suppression of the maximum response

  • degree of suppression is dependent on conc of the antagonist
  • block by antagonist is not surmountable by increasing agonist conv
  • this type of binding cannot be overcome by function of time, antagonist conc, drug metabolism and insertion of new receptors into the membrane
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23
Q

drug potency- what is the most effective drug?

A

one that works at minimal concs

24
Q

chemotherapeutic agents - amoxicillin mechanism

A

inhibits synthesis of peptidoglycan - which forms the bacterial cell wall

25
Q

chemotherapeutic agents - erythromycin mechanism

A

inhibits protein synthesis by action on 50s ribosomal subunit

26
Q

chemotherapeutic agents - tetracycline mechanism

A

taken up selectively into precaryotic cells inhibits protein synth by competing with tRNA for binding to ribosome

27
Q

chemotherapeutic agents - metronidazole mechanism

A

cause DNA strand breakage ; taken into cells and reduced to active form; reduction foes not occur in mammalian cells

28
Q

what drug names do drugs have (3 types)

A

proprietary
common
chemical

29
Q

what is Pharmacodynamics

A

describes what the drug does to an organism

-sum of all of the actions of a drug, incl side effects

30
Q

what is pharmacokinetics?

A

describes what the organism does to a drug

-(absorption, distribution, metabolism and excretion)

31
Q

what does pharmacokinetics determine?

A

how quickly it acts in a patient

  • whether the target area is local or systemic
  • how long the effects last
32
Q

what is drug absorption governed by? And why?

A

lipid solubility

- as unless drug is injected intravenously it must pass several lipid bilayers

33
Q

what are local anaesthetics?

A

weak bases

34
Q

where are drugs given orally absorbed?

A

small intestine

- enter the portal circulation and then the liver where they may be extensively metabolised

35
Q

what is bioavailability?

A

the proportion of drug reaching the circulation

36
Q

absorption and distribution - when drug enters circulation where does it go?

A

rapidly distributed around the body but then must penetrate the tissues to work

37
Q

absorption and distribution - what are drugs bound to? what is the effect of this?

A

plasma proteins

-slows entrance into tissues

38
Q

drug elimination - how are drugs eliminated from the body?

A

metabolism and excretion

39
Q

drug elimination - what is the metabolism of drugs?

A

the conversion of drugs from one molecule to another which may be active or inactive

40
Q

drug elimination - what are the phase 1 reactions

A

Catabolic reactions which break down the drug into products which may be more toxic or active than the current drug

41
Q

drug elimination - what are the phase 2 reactions

A

Synthetic reactions involving conjugation of chemical groups to produce drugs that may be water soluble.

42
Q

drug elimination - where does detoxification of drugs usually take place?

A

liver

43
Q

drug elimination - where else than liver can metabolism take place

A

plasma, gut and the lungs

44
Q

drug elimination - where are most enzymes catalysing phase 1 reactions

A

liver cells in smooth ER (microsomal enzymes)

45
Q

drug elimination - what can these microsomal enzymes be induced by?

A

some other drugs

effect ; speeding the metabolism of other drugs

46
Q

drug elimination - where is drug excretion?

A

mainly via kidneys

47
Q

drug elimination - how do drugs enter the kidneys?

A
48
Q

drug elimination - lipophilic drugs

A

can easily diffuse out of nephrons and back into the blood so aren’t removed well

49
Q

drug elimination - what is the half life of a drug

A

time taken for the substance to halve from its original amount

50
Q

drug elimination - what is the effect of age on elimination

A

decreases with age so elderly take smaller doses

51
Q

Drug Interactions - pharmacodynamic interactions

A

drugs which have similar or opposite actions or side effects

52
Q

drug interactions - pharmacokinetic

A

A drug which alters the absorption, metabolism, distribution and excretion of another drug

53
Q

drug interactions - what can occur when there is induction of hepatic enzymes by drugs

A
  • can decrease the effectiveness of other drugs which are metabolised by the enzymes
  • can increase the effect of other drugs which are metabolised by these enzymes
    e. g. erythromycin and midazolam
54
Q

Clinical Phases of Drug Testing - what occurs in phase I

A
  • Small Scale
  • Use healthy volunteers
  • Test for pharmacokinetics, side effects and potency
55
Q

Clinical Phases of Drug Testing - what occurs in phase II

A
  • Medium Scale
  • Use patient volunteers
  • Test for efficacy of drug and to find the optimum dosage
56
Q

Clinical Phases of Drug Testing - what occurs in phase III

A
  • Large scale
  • Again using patient volunteers
  • Test for efficacy, optimise the dosage, incidence of side effects
  • Double blind trial is usually done to compare new drug with current drugs or a placebo
57
Q

Clinical Phases of Drug Testing - what occurs in phase IV - post licencing

A

• Drug is monitored for efficacy and safety