2 -Pharmacodynamics Flashcards Preview

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Flashcards in 2 -Pharmacodynamics Deck (30):
1

Define pharmacodynamics

Effect of body on drugs

2

Define agonist

Binds to endogenous proteins and activates them

3

Define antagonist

Bind to endogenous proteins, block and inhibit them

4

What is the difference between competitive and non competitive antagonists?

The site at which they bind
Competitive bind to the same site as the agonist and block the receptor
Non competitive bind to an alternate site and cause a conformational change in the receptor that prevent agonists from binding

5

What is a highly selective drug?

One that has minimal interaction with other targets, producing few side effects

6

What does it mean if a drug is highly specific?

Can be targeted to specific organs due to the receptors present

7

Which organs are B1 and B2 receptors found?

B1 heart
B2 lungs

8

Define affinity

Tendency of a drug to bind to a specific receptor type, the higher the affinity the greater the tendency to bind

9

Define efficacy

Ability of a drug to produce response as receptor is occupied, describes the max effect of a drug

10

Define potency

Dose required to produce desired biological response, different doses of 2 drugs to produce same response

11

What is therapeutic index?

Relationship between concentrations for desired and adverse effects
Toxic dose / effective dose

12

Define therapeutic window

Range of doses that effectively treat while still remaining safe pm between lowest dose that still has a positive effect and highest dose before negative effects outweigh positive

13

Describe how paracetamol absorption changes with alcohol

Paracetamol with alcohol and food lower than just alcohol

14

How is the absorption of tetracycline altered with ferrous?

Concentration of tetracycline decreases with addition of ferrous (Fe 2+)

15

What types of drug are protein binding interactions important for?

IV drugs
Short half lives
Narrow therapeutic windows

16

Which CYP metabolises warfarin?

CYP2C9

17

Which CYP metabolises codeine?

CYP2D6

18

What effect does codeine have on alcohol absorption?

Codeine slows gastric emptying, so less alcohol absorbed

19

Give an example of agonist/antagonism at the same receptor

Beta blockers and B2 agonists

20

Give an example of agonism/antagonism at different receptors

Warfarin and aspirin

21

What receptors are activated by anti depressants?

Adrenergic
Cholinergic
Noradrenergic
Na channels
Serotoninergic

22

What drugs can interact with digoxin to cause toxicity?

Loop diuretics, causing hypokalaemia

23

How does renal disease effect drug interactions?

Fall in GFR - reduced clearance
Disturbance of electrolytes predisposes to toxicity
Nephrotoxins allowed to build up, further damaging kidneys

24

How does hepatic disease affect drug interactions?

Reduced clearance
Reduced CYP 450 activity
Longer half lives
Increased toxicity

25

How does cardiac disease affect drug interactions?

Excessive response to hypotensive agents, drugs remain in subcutaneous tissue
Reduced organ perfusion, reduced blood flow to liver and kidneys, reduced clearance

26

Describe the effects of grapefruit juice on drug metabolism

Inhibits CYP 450 enzymes
Reduced clearance
Increased exposure to drugs

27

Describe the effect cranberry juice has on drug metabolism

Inhibits CYP2C9
Decreases metabolism of warfarin, increasing anticoagulative effects, increased risk of haemorrhage

28

Define an adverse drug reaction

Unwanted reaction occurring after administration of a drug

29

What increases the risk of an adverse drug reaction?

Poor prescription
Co morbidities
Extremities of age - altered pharmacokinetics
Narrow therapeutic indexes
Minimum effective dose prescription, risk of treatment failure if metabolism increases

30

Name some causes of variation in drug response

Biological: age, sex, body weight, genetics, co-morbidities, placebo effect
Pharmalogical: dose, formulation, route of administration, repeat administration (allergy/resistance), drug interactions