Session 2 - Pharmacodynamics and Pharmacokinetics 2 Flashcards

1
Q

What is a partial agonist?

A

Agonist cannot enact 100% response. When in solution with an agonist can act as a competitive antagonist

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2
Q

What is drug Specificity and drug selectivity?

A

Specificity - Targets only one subtype of a receptor e.g. beta2

Selectivity - Targets all types of a particular receptor e.g. beta receptors

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3
Q

What is affinity?

A

Tendency of a drug to bind to a specific receptor type

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4
Q

What is efficacy?

A

Ability of a drug to produce a response as a result of receptor being occupied

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5
Q

What is potency?

A

Dose required to produce the desired biologic response

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6
Q

How do you calculate the therapeutic index of a drug?

A

EC50 (adverse effect) / EC50 (desired effect)

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7
Q

How do you calculate the Vd?

A

Vd = Dose/[Drug]t0

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8
Q

What effect does grapefruit juice have on enzymes?

A

Inhibits several CYP450 isoenzymes

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9
Q

What effect does cranberry juice have on enzymes?

A

inhibits CYP2C9 isoform enzyme

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10
Q

How can liver failure impact on drug clearance?

A

Increased half life, less enzymes

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11
Q

How can cardiac disease impact drug clearance?

A

Reduced organ perfusion of liver and kidneys

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12
Q

How does renal failure impact drug clearance?

A

Less quickly eliminated through waste

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13
Q

How would you calculate the loading dose necessary for a drug?

A

Loading dose = Vd x [drug]target

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14
Q

What is the relationship between half life of drug and volume of distribution?

A

Higher volume of distribution = higher half life

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15
Q

How does the multi compartment model affect drug clearance?

A

Drug can be excreted from different compartments (muscle, fat, plasma) at different rates

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16
Q

What are the main routes of administration via the enteral route?

A

oral, rectal, sublingual

17
Q

What are the primary parenteral routes?

A

intravenous, intra-arterial, intramuscular, intrathecal, subcutaneous

18
Q

What are the pros and cons of enteral?

A

pros - cheaper, easier to use, can self administer

cons - drug can be metabolised, slower onset, irritates GI, unsuitable if vomiting (oral)

19
Q

What are the pros and cons of parenteral?

A

Pros - quick onset, no degradation, dosing can be exact

Cons - must be sterile, requires HCPs, more expensive, unconvenient

20
Q

What are the pros and cons of transdermal delivery?

A

Pros - steady rate of drug delivery, avoid breakdown by liver

Cons - Suitable only for lipid soluble drugs, relatively expensive

21
Q

Some drugs work at a concentration in the plasma that approaches total saturation of the serum albumin. Why would increasing the dosage of such a drug have a disproportionate effect on the body?

A

Only the unbound molecules are active. Increasing drug conc when total saturation has reached would result in far more unbound molecules than in previous increases of drug conc

22
Q

How does the blood flow through adipose tissue affect uptake of drugs into adipose?

A

Body fat has a low blood supply and therefore when drugs are administered acutely only very lipid soluble drugs will partition siginificantly into fat.

However, when a drug is administered chronically then levels of that drug can build up over time in the fat stores

23
Q

What pH drug does albumin mainly bind?

A

Acidic drugs

24
Q

What 2 factors concerning the drug itself determine the rate of drug absorption from the intestine?

A

Lipid solubility and ionisation

25
Q

Define bioequivalence

A

2 drugs that are expected to act in a very similar way

26
Q
A