Pharmacology Flashcards

1
Q

In regards to pharmacology, what is the body considered as ?

A

One compartment

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2
Q

What is the magnitude of the drug effect associated to ?

A

The amount of drug available on the plasma/ blood.

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3
Q

What does passive diffusion depend on ?

A

Depends on the ability of drug (physiochemical characteristics) crossing lipid bilayer membrane

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4
Q

What does active diffusion require ?

A

Require transporter/carrier for the uptake of drug across cell membrane

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5
Q

What is the major mechanism of drug delivery ?

A

Passive diffusion

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6
Q

What does rate of diffusion depend on ?

A
  • surface area
  • thickness of membrane
  • molecular size and lipid solubility (diffusion constant)
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7
Q

What are the names of the transporters that low lipid soluble (hydrophilic) drugs use ?

A

Organic anion transporters (OATs)
Organic cation transporters (OCTs)

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8
Q

Which drugs will cross the lipid belayers by passive diffusion ?

A

Un-ionised only drugs

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9
Q

What’s the pH of the mouth ?

A

7.4

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10
Q

What is the pH of the stomach

A

1.5

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11
Q

What’s the pH of the small intestine ?

A

5.3

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12
Q

What factors affect ionisation ?

A
  • pH (i.e. concentration of H+ ions)
  • pKa of drug
    (pH at which 50% of molecules are in each state)
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13
Q

What will the precise degree of ionisation be determined by ?

A

The pKa and exact pH

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14
Q

What factors influence G.I absorption ?

A
  • G.I. motility
  • G.I. secretions & enzymes
  • drug-food/supplement interactions
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15
Q

What are the advantages of G.I absorption ?

A
  • Large surface area for passive diffusion
  • Range of pH environments promote uptake of weak acids/bases
  • Richly vascularised (high blood supply)
  • Long tract and long dwell time
  • Some active transport (e.g. Levodopa taken up by phenylalanine transporter)
  • Small intestine is a major site for drug absorption
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16
Q

What is bioavailability ?

A

A measure of the proportion of the dose absorbed compared to I.V dose

17
Q

What is time to peak (t max) ?

A

Time to peak (tmax): time required to reach maximum drug concentration in plasma (is a measure of rate of absorption)

18
Q

What is the major site or drug absorption ?

A

Small intestine

19
Q

What does the rate of absorption depend on ?

A
  • Vascularisation of site of absorption
  • Characteristics of formulation/dosage forms
  • lipid solubility of the drug
  • pH of the site of absorption
20
Q

The free or bound drug is in ___________ equilibrium ?

A

Dynamic

21
Q

What plasma proteins do acidic and neutral drugs bind to ?

A

Albumin (warfarin)

22
Q

What plasma proteins do basic drugs bind to ?

A

Beta-globulins (quinine)

23
Q

What does high binding of drugs to place proteins cause ?

A

Less drugs available for target action

24
Q

How do drugs bind to plasma proteins ?

A

Reversibly

25
Q

What affects the kinetics of drug distribution ?

A
  • the blood supply
  • lipid solubility
  • tissue depots
26
Q

What does volume of distribution (Vd) indicate ?

A

the theoretical distribution of drugs in various fluid and tissue compartments