Drugs Handling In The Body

Question 1

Name 2 positive aspects of oral administration?

Answer 1

Convenient for patient

Absorption for small intestine- large surface area

Question 2

Identify the negatives of oral administration

Answer 2

Not appropriate for all drugs
Absorption is variable eg how lipid soluble is the drug
Absorption depends on stomach content (may be destroyed)
Rate of gastric emptying
Degradation in stomach

Question 3

Define bioavailability

Answer 3

Is the amount of dose which reaches circulation as intact drug

Question 4

Name the positives of topical administration and define it?

Answer 4

Skin creams and convenient and poorly absorbed which reduces the risk of overdosing

Question 5

Name the negatives of tropical administration

Answer 5

Negative effects on skin eg hydrocortisone causes thinning of the skin

Question 6

Define transdermal administration and explain the benefits

Answer 6

Long acting
Useful when you want low levels over a long period of time
Suitable for wide patient groups

Question 7

Name the negatives of transdermal administration

Answer 7

Variable absorption
Drug must be lipid soluble
Drug must be potent

Question 8

Name 2 positives and 1 negative of rectal administration

Answer 8

+ local or systemic effect
Useful if vomiting or can’t swallow
- trained to administer

Question 9

Name 2 positives and 1 negative of inhalation administration

Answer 9

+rapid change in conc of drug due to LSA of lungs
Local or systemic effect
-difficult to ensure drugs reach site of action

Question 10

Name 6 parenteral routes

Answer 10

Intravenous, intramuscular, intradermal, subcutaneous, intrathecal, epidural

Question 11

Name the positives of the parenteral routes

Answer 11

Rapid action
Bypass stomach and liver
Lower dose required
Patient controlled syringe drivers

Question 12

Describe the negatives associated with parenteral routes

Answer 12

Required trained person
Extreme care required
Accidental overdose
Painful

Question 13

What are excipients ?

Answer 13

These are additional components added to the drug to turn into a medicine, may improve taste or stabilise drug

Question 14

A medicine = a active drug + _________

Answer 14

Excipients

Question 15

Excipients can impact upon

Answer 15

Bioavailability and duration of therapeutic effect

Question 16

Describe the chain of events which occur in the absorption of oral tablets

Answer 16

Tablet > granules > fine particals > solutions

Question 17

Define dissolution rate

Answer 17

How fast it becomes a solution

Question 18

For a drug to cross a cell membrane they must be lipid soluble or water soluble ?

Answer 18

Lipid soluble

Question 19

Name 4 method of drugs crossing a cell membrane

Answer 19

Passage trough water channels
Endocytosis
Passive diffusion
Facilitated or active transport

Question 20

Distribution is the

Answer 20

Transfer of absorbed drug into and out of various tissues in the body from the blood stream

Question 21

What effects the extent of distribution

Answer 21

Lipid solubility of drug
Blood flow to tissues
Binding of drugs to proteins

Question 22

Free drugs can bind to ______ in the plasma, and only ______ unbound drugs can diffuse across membranes and have an effect

Answer 22

Proteins

Free

Question 23

Elimination =

Answer 23

Metabolism + excretion

Question 24

Most drugs are lipophilic what does this mean ?

Answer 24

They re-circulate ( as they are just reabsorbed back into blood stream when they reach liver)

Question 25

In order to stop recirculating drugs must be converted to what ????

Answer 25

Water soluble

Lipid soluble > water soluble > excretion

Question 26

Drugs metabolism is the _____ conversion of _______ soluble into a more _______ soluble one

Answer 26

Enzyme mediated
Lipid
Water

Question 27

Metabolism mainly takes place in the …

Answer 27

Liver, kidney, lungs, GI tract, brain and plasma

Question 28

Name the phases of metabolism

Answer 28

Phase 1 and phase 2

Question 29

Explain what happens in phase 1

Answer 29

Modifies chemical structure of drug to make it slightly more water soluble and prep for phase 2

Question 30

Explain pharmacological activation and identity which phase it occurs in

Answer 30

Is when drugs have to be metabolised to be activated and in phase one as products can be more reactive that parent drug

Question 31

Explain what happens in phase 2

Answer 31

Conjugate drug to large molecules eg amino acids + sulphate groups

Question 32

The products of phase 2 are generally

Answer 32

Water soluble and easily excreted
Increase molecular weight 
Inactive (pharmacological inactivation)
> decreased receptor affinity 
Enhanced excretion

Question 33

With drug interactions, Drugs metabolising enzymes can either be what ?

Answer 33

Induced eg alcohol induced liver enzymes

Inhibit eg fluoxetine( Prozac) + grapefruit juice

Question 34

Excretion is the

Answer 34

Removal of drugs from the body

Question 35

Excretion takes places via

Answer 35

Urine, bile, faeces, lungs and skin

Question 36

To increase drug excretion;

Answer 36

Increase blood flow to kidneys

Decrease plasma protein binding

Question 37

Half life is ….

Answer 37

The time is takes for the amount of drug in the body to decrease to one half of the peak level- this is the rate at which drugs are eliminated from the body

Question 38

Most of drug (97%) is eliminated after how many half life’s?

Answer 38

5 regardless of dose of route

Question 39

What does the half life tell us ?

Answer 39

The time we should leave between stoping one drug and starting the next to avoid interactions
Estimates how long it takes for toxic concentration to occur

Question 40

What is at the top and bottom of the therapeutic window ?

Answer 40

Top is min toxic concentration

Bottom in min therapeutic concentration

Question 41

Name the 6 routes of transmission

Answer 41

Oral, topical, transdermal, rectal, inhalation, parental