Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

General Ocular Pharmacology > Administration . Absorption and Distribution of Drugs > Flashcards

Administration . Absorption and Distribution of Drugs Flashcards

1
Q

Pharmacokinetics is …

A

How the body affects a specific drug after administration

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Draw and lablel the pharmacokinetic curve

Briefly explain what is happening at each interval

A

Refer to Notes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

The administration of drugs can be classified into different groups . What are they?

A

Enteral

Parenteral

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

A drug that is administered via the enteral route involves ..

A 
Mouth
oesophagus 
stomach 
small and large intestines 
constituents of the GI tract
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

A drug that is administered via the parenteral route involves ..

A

may cross epithelium if applied topically to skin

or may avoid epithelium through inhalation and absorbed by lungs or forms of injections

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

State the enteral routes of administration

A

sublingual
oral
buccal
rectal

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

state the parenteral routes of administration

A

injections
inhalations
cutaneous

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What is an intrathecal injection

A

an injection into the spinal canal or into subarachnoid space so it reaches the cerebrospinal fluid

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

what is an intraperitoneal injection

A

an injection made into the body cavity - LBP pts

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

discuss what you know about the sublingual route of administration

A

sublingual means under the tongue
involves placing pill or spray under the tongue and floor of oral cavity
connective tissue in this area is highly perfused which means drug only has to interact with these enzymes - liver is bypassed
rapid means of absorption
ideal for emergency conditions like use of GTN for rapid relief of sx of angina

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Discuss what you know about the buccal route of administration

A

buccal means between pts cheeck and gum - not swallowed
liver bypassed
presence of saliva help breakdown of drug
taste may not be nice

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What is meant by the first pass effect ?

A

a concept where conc of drug avail to reach the systemic circulation is reduced due to processes it undergoes like metabolism

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Cirrhosis is

A

Cirrhosis is the severe scarring of the liver and poor liver function The scarring is most often caused by long-term exposure to toxins such as alcohol or viral infections.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Draw and label a diagram of the hepatic portal system

A

Refer to notes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What does the hepatic portal system do

A

carries blood from parts of the GI tract to the liver

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Give examples of oral drug forms

A

Capsules - less compressed together , shell of capsule dissolves then contents free
tablets - compressed - disintegrates into smaller
pills
enteric coatings - barrier applied to tablet to protect t from the acidity of the stomach , in other conditions able to break down
elixirs - active ingredient mixed with liquid
suspensions - liquid with small pieces of drug. drug is not completely dissolved in drug

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Briefly discuss what you know about the rectal form of drug administration

A

end of GI tract using suppository
absorbed by the rectums blood vessels
useful for vomiting patients unable to keep anything down
surface area avail for absorption is reduced - no microvilli
allows some bypassing of the first pass effect because venous drainage in this area done by inferior and middle rectal vein with minimal help from hepatic porta system

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

state the factors which influence absorption of drugs in the GI tract

A
  • Surface Area
  • PH of gastro intestinal contents
  • Active transport
  • Plasma protein binding
  • Gastric emptying
  • blood flow
  • formulation
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

PH of gastro intestinal contents

A

the PH conditions will affect the ionisation of molecules
ionisation is process by which molecules that lose electron gain positive charge and molecules that gain electron gain a negative charge.
- mucosa lining of GI tract - impermeable to ionised molecules
- acidic drugs –> acidic conditions of stomach stay in un ionised formed and absorbed in stomach

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Surface Area

A

small intestine - high conc of microvilli so has larger surface area 1000x more than of stomach - absorption more efficient in areas of great SA

21
Q

Gastric emptying

A

Related to how fast drug/food leaves the stomach . If drug moves quickly absorption will be reduced

22
Q

Blood flow

A

intestine - good blood flow- maintains conc gradient . Drug moves from high to low conc
BF to intestine is greater than stomach - absorption favoured here

23
Q

Plasma Protein Binding

A

drug molecules may bind to plasma protein and if occurs it will become inactive .
only free drug molecules can be pharmacologically active

24
Q

Formulation

A

small particle size - faster rate of absorption

large particle size - delayers absorption

25
Q

Active Transport

A

Transportation of molecules across membranes ( passive or active )

26
Q

What is an intravenous injection

A

substance that is given directly into vein
all of it enters systemic circulation
useful for quick rapid response

27
Q

Disadvantages of intravenous injection

A

requires trained personnel
sometimes difficult to find vein
expensive ( sterility / cost of preparation and transport/storage)

28
Q

what is a subcutaneous injection

A

substance administered into the subcutis layer
often used to deliver vac and meds ( insulin)
layer has few BV - slows absorption - massage to help
to maintains effect locally - vasoconstriction ( painful / finding site for repeated injection can be issue)

29
Q

what is an intramuscular injection

A

substance given directly into muscle
lots of BV - faster absorption
used to deliver large volume of meds - antipsychotic drugs - lasting effects
- requires trained personnel

30
Q

sites for intramuscular injection depend on what?

A

pts age
type of drug
volume

31
Q

state the different sites for intramuscular injections

A

deltoid muscle of arm - small volume
vastus lateralis - newborns and infants
ventrogluteal - pts lying on side ( most comf and safe for adults )
dorsogluteal (less likely to be used due to proximity to sciatic nerve) last resort in adults.

32
Q

Explain the inhalation route of administration of a drug

A

pt inhales - lung , has a large SA and BF rapid absorption
bypasses liver and first pass effect
absorption of gasses relatively efficient - Larger particle size = less absorption and more local action, small particle size = favours systemic absorption

33
Q

What is absorption ?

A

transfer of drug from site of administration into the blood stream

34
Q

in order for a drug to get into the bloodstream what does it have to cross

A

several semi permeable membranes

35
Q

what is a cell membrane made up of

A

phospholipid bilayer

  • hydrophillic heads - phosphate
  • hydrophobic tails - two fatty acid chains
  • layer is 10nm thick
36
Q

how do small molecules cross cell membranes

A
  • forces that hold the CM - weak - drugs may be able to slip through lipids in bilayer . Can only happen if drug is small , lipid soluble and lipophilic
  • some drugs may need help so travel through aqueous pores
  • specific molecules may recognise certain drugs and help them cross using carrier molecules
    passively ( s energy) or actively
  • pinoocytosis
37
Q

what do you know about diffusion

A 
passive process 
requires conc gradient
particle size - small 
membrane - permeable 
ability of drug to pass through membrane depends on lipid solubility
38
Q

what is lipid solubility

A

ability of drug to dissolve in lipid

39
Q

what is facilitated diffusion

A

drug molecules combine with carrier proteins to transport through membrane
specific - only recognised molecules
flows with conc gradient

40
Q

what is active transport

A

requires energy ATP

goes against conc gradient

41
Q

what is pinocytosis

A

form of endocytosis
molecules bought into cell when part of cell membrane encloses around them and makes then move from outside to inside of cell
molecules may be released into cell or remain in vesicle

42
Q

What is distribution?

A

once drug has reaches bloodstream it circulates around the body - and will move into tissues of the body and site of action

43
Q

quantify distribution

A

apparent volume of distribution linked to conc present in plasma

44
Q

water of body can be distributed into four parts in the body . what are they and how much does each represent

A

Refer to notes

45
Q

Briefly explain the effect of solubility on a drug

A

if a drug is lipid soluble it will be able to pass through the cell membrane easily and reach all fluid compartments and have widespread distribution

if a drug is water soluble it will be difficult to cross the cell membrane , it will stay in the plasma and interstitial fluid and continue circulating leaving itself open to be metabolised by the liver and eliminated without reaching tissue

46
Q

Give an example of plasma protein and give an example of a drug which binds to a protein

A

Albumin

  • warfarin 97% binds to protein leaving only 3% to be active , metabolised and excreted
47
Q

what drugs will bind to the protein albumin

A
  • bind likely to acidic drugs
    if that becomes saturated - lipoprotein
  • basic drugs - alpha 1 acid glycoprotein
48
Q

what is volume of distribution

A

theoretical volume required to contain the total amount of administered drug at the same conc as the plasma

Vd = total amount of drug in body/ drug blood plasma conc

49
Q

importance of blood flow

A

heart liver kidney and brain - seconds to mins

muscles , skin , fat
mins - hours

bones
- days - weeks

General Ocular Pharmacology (6 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions