pharmacology

Question 1

name some drugs that are associated with a high risk of falls

Answer 1

antidepressants and antipsychotics
anticholinergics
benzos

Question 2

what is anticholinergic burden

Answer 2

cumulative effect of one or more medications with anticholinergic activity

Question 3

what is the consequence of anticholinergic burden in the long term

Answer 3

increases the risk of dementia and reduced physical function

Question 4

what are some physical consequences of anticholinergic burden

Answer 4

blurred vision, dry eyes
constipation
dry mouth
drowsiness, confusion, hallucinations, dizziness
rapid HR
urinary retention

Question 5

name some types of drugs with high anticholinergic activity

Answer 5

tricyclics, antipsychotics
urinary antispasmodics e.g. tolterodine
antihistamines
H2 receptor antagonists
spasticity agents e.g. diazepam

Question 6

what are the 4 main components of pharmacokinetics

Answer 6

absorption
distribution
metabolism
excretion

Question 7

what is the main pharmacokinetic principle around absorption of a drug

Answer 7

acidic drugs require an acidic environment for absorption and basic drugs require a basic environment

Question 8

name some acidic drugs

Answer 8

phenytoin, penicillin, aspirin

Question 9

what class of drug should NOT be taken with acidic drugs as the interrupt absorption

Answer 9

PPIs

Question 10

which type of drug is best absorbed by older patients and why - acidic or basic

Answer 10

BASIC
increase in gastric pH due to less parietal cells producing stomach acid
reduced surface area of small bowel

Question 11

when does absorption of drugs become a problem in older patients

Answer 11

previous GI surgery
tube feeding
transdermal patches and oedema

Question 12

what are the 2 main binding proteins for drugs and what do they bind to

Answer 12

albumin binds to acidic drugs
alpha-1 acid glycoprotein bind to basic drugs

Question 13

which drug binding proteins do elderly patients tend to have/less more of, and what is the consequence of this

Answer 13

low albumin and high A-1 AG so more binding of basic drugs

Question 14

how does fat percentage in patients change in older patients and what effect does this have on the distribution of drugs

Answer 14

increases the volume of distribution of lipophilic drugs meaning they have a longer half life

Question 15

what is the volume of distribution

Answer 15

the theoretical volume into which all of a drug is fully dissolved in plasma

Question 16

what is the Vd of a drug an indicator of

Answer 16

how lipophilic a drug is - how much drug is sequestered into fatty tissue

Question 17

what is the consequence of a drug having a high Vd

Answer 17

longer half life

Question 18

what is the half life of a drug

Answer 18

time for drug concentration to fall to half of its maximum concentration

Question 19

how do we calculate the half life of a drug

Answer 19

(0.693 x Vd) / clearance

Question 20

how does body water percentage differ in older patients and what is the effect of this on the distribution of drugs

Answer 20

body water decreases with age
lowers the Vd of hydrophilic drugs

Question 21

why is t1/2 usually unchanged in elderly patients even though body water decreases

Answer 21

lower Vd but proportionally lower clearance so remains unchanged

Question 22

why does liver function tend to decline in older patients (3)

Answer 22

decreased liver size
decreased blood flow
disease

Question 23

what is a consequence of reduced liver function on metabolism

Answer 23

first pass metabolism reduced

Question 24

what is first pass metabolism

Answer 24

medication undergoes metabolism at a specific location in the body, decreasing the active concentration upon reaching systemic circulation or its site of action

Question 25

what phase of drug metabolism is usually affected by age

Answer 25

phase 1 pathways

Question 26

what happens in phase 1 of drug metabolism

Answer 26

functionalisation reaction - oxidation, reduction or hydrolysis

Question 27

what catalyses phase 1 of drug metabolism

Answer 27

P450 system

Question 28

what is the role of phase 2 of drug metabolism

Answer 28

conjugation - produces products that are water soluble and easily secreted by the kidneys

Question 29

what is the general consequence on drug metabolism in older patients

Answer 29

bio-transforming enzymes are reduced

Question 30

what happens to GFR in older patients and why

Answer 30

decreases with age decreased size, tubular secretion and renal blood flow

Question 31

what is the general principle of pharmacodynamics in older patients

Answer 31

lower doses achieve the same effect

Question 32

what happens to therapeutic window of a drug with age

Answer 32

gets smaller

Question 33

how do we calculate therapeutic index of a drug, and what number should we be concerned about in elderly patients

Answer 33

50% of lethal dose / 50% of effective dose index <2

Question 34

what is a common side of opioids in the elderly and how do we combat this

Answer 34

constipation prophylactic laxatives

Question 35

what is a side effect of long term steroids we need to be aware of, especially in the elderly

Answer 35

osteoporosis

Question 36

what type of painkiller should be avoided in elderly patients and why

Answer 36

NSAIDs risk of GI haemorrhage, decrease in GFR

Question 37

what criteria is useful for clinicians when reviewing medications in elderly patients

Answer 37

STOPP-START

Question 38

name some reasons why elderly patients have issues with drug adherence

Answer 38

difficulty opening pill containers understanding how and when to take it remembering to take it

Question 39

what is the most important isoenzyme involved in drug metabolism

Answer 39

CYP3A4