questions

Question 1

What is metformins mode of action?

Answer 1

• Reduces glucose produced by the liver
• increases sensitivity of muscles cells to insulin produced
• delays transfer of glucose from intestinal tract to blood after meal

Question 2

Metformin half life?

Answer 2

Three hours

Question 3

Onset to drug action of metformin?

Answer 3

2.5 hrs

Question 4

Name a plasma protein and drug which is highly plasma protein bound

Discuss their role in binding drugs and affecting their availability for pharmacodynamic action

Answer 4

Albumin

Warfarin

Drugs bound are pharmacologically inert, don’t reach site of action

Can mean oral dose is greater than needed due to bioavailability being reduced due to plasma protein bonding

Can be displaced by other drugs from their binding sites

Question 5

What is bioavailability?

Answer 5

Percentage of administered drug that reaches systemic circulation after absorption

Question 6

What is steady state?

Answer 6

When drug going into the body is equal to going out, achieved after 5 half lives

Question 7

Which organ produces plasma proteins?

Answer 7

Liver

In liver disease there are changes to plasma proteins meaning less of the drug is protein bound and more of the drug can exert effect- lower dose needed

Question 8

Example for pharmacokinetic drug interaction

Answer 8

Can occur when drug alters after adme eg magnesium reduces ansorbion of iron so should be separated by time (in bnf)

Question 9

Example of pharmacodynamic interaction

Answer 9

Competition at receptor sites eg propanalol (antagonist) and salbutamol (agonist)

Question 10

2 types of ADRs

Answer 10

Augmented- predicted by pharmacology

Bizarre- wholly unpredictable eg anaphylaxis

Question 11

How to avoid/minimise ADRs

Answer 11

Prescribe familiar drugs
Only prescribe if indicated
Check for allergies
Ref meds reviews to check for polypharmacy
Give clear instruction to the pt
Check bloods
Advise others of potential side effects
Previous reactions to medications

Question 12

What is an ADR

Answer 12

Unwanted or harmful reaction, always unwanted

Question 13

What to consider when prescribing in the elderly

Answer 13

Decreased metabolism and excretion
Polypharmacy
Check for renal/liver impairment
Only prescribe if good indication
Review regularly
Check nutrition status

Question 14

Factors to consider when prescribing in renal impairment

Answer 14

Only px if definite indication
Choose drug with minimal nephrotoxicity
Monitor pt carefully- rev bloods

Question 15

Factors to consider when prescribing a drug

Answer 15

Route
Allergies
Co morbidities
Age
Other medications
Patient agreement

Question 16

What factors influence metabolism?

Answer 16

Genetics
Age- 1st pass maybe reduced in older people

Liver and cardiac disease (reduced blood flow in cardiac, liver disease reduces metabolic potential

Question 17

What factors can influence ‘time to onset’

Answer 17

Route of administration
Rate at which it is absorbed
How it is distributed by the body

Question 18

What are pharmacokinetics?

Answer 18

The way the drugs move through the body

Question 19

Pharmacodynamics?

Answer 19

The effect the drug has on the body

Question 20

Physiological factors affecting absorption

Answer 20

Blood flow

Total surface area (intestine, large surface area)

Contact time at site

Question 21

Physio chemical factors affecting absorption

Answer 21

Solubility

Chemical stability

Lipid to water partition coefficient (cells made from phospho-lipid layer- drugs dissolve well in lipids eg anaesthetic, benzodiazepines

Degree of ionisation

Question 22

What affects distribution

Answer 22

Distribution of body fluids (plasma, interstitial, and intercellular fluid)

Uptake to organs (eg iodine- thyroid gland)

Extent of plasma protein binding

Passage through barriers (eg placenta)

Question 23

2 phases of metabolism

Answer 23

Phase 1- oxidation (chemical reaction that changes drug properties), reduction, hydrolysis

Phase 2- conjugation

Question 24

What factors affect metabolism?

Answer 24

Nutrition

Age- enzyme activity declines

Alcohol

Genetics

Disease process, such as heart failure

Question 25

Where does excretion mainly take place? And how?

Answer 25

Kidney

Via renal elimination- active glomeral filtration (ionised drugs are secreted into proximal tubule and pushed out into urine

Distal tubule- passive reabsorotion and excretion of drug by taking drug from high to low concentration by diffusion

Question 26

Object of medication review

Answer 26

Check pts understanding
Reduce polypharmacy
Check bloods
Check concordance
ADRs
Side effects

Question 27

Ligand

Answer 27

Chemical/drug that binds to a receptor (benzodiazepine)

Question 28

Ion channel

Answer 28

Provide receptors which drugs can react with (blockers and modulators)

Question 29

What is an enzyme?

Answer 29

Biological catalyst that increase rate of chemical reaction eg elanopril (acei)

Question 30

Eg of transport systems?

Answer 30

Serotonin released from neurone-taken back up by same neurone using serotonin re uptake system (recycling)

Fluoxetine blocks uptake transporter- resulting in increased serotonin (increase in mood)

Question 31

What is biotransformation?

Answer 31

Process of metabolising drugs

Mainly in the liver

Question 32

Eg of a pro drug

Answer 32

Aspirin

Drugs which are activated by metabolism