Pharmacology

Question 1

what is meant by pharmacokinetics?

Answer 1

absorption, distribution, metabolism, excretion

Question 2

what is meant by pharmacodynamics?

Answer 2

drug action on body

Question 3

in which 3 conditions should you reduce dose of drugs?

Answer 3

age >75
weight <60kg
impaired renal function

Question 4

what type of environment do acidic drugs need for absorption?

Answer 4

acidic

Question 5

give examples of acidic drugs?

Answer 5

phenytoin
aspirin
penicillins

Question 6

what type of environment do basic drugs require for absorption?

Answer 6

basic

Question 7

what are features of older peoples stomach acid and small bowel surface area which makes more basic drugs be absorbed?

Answer 7

stomach acid - more basic

small bowel surface area - decreased

Question 8

older peoples stomach acid being more basic and small bowel surface area being decreased does not usually pose a problem except in what circumstances?

Answer 8

previous GI surgery
NG tube or PEG feed
transdermal patches and oedema
or if more basic drugs absorbed

Question 9

give examples of basic drugs?

Answer 9

diazepam
morphine
pethidine

Question 10

distribution of drugs can be by which two binding mechanisms?

Answer 10

protein binding

lipid binding

Question 11

what protein binds to acidic drugs?

Answer 11

albumin (basic)

elderly = lower

Question 12

what protein binds to basic drugs?

Answer 12

alpha-1 acidic glycoprotein (acidic)

older = higher

Question 13

what increases lipid binding?

Answer 13

increased fat (proportional to muscle mass)

increases VD of lipophilic drugs (eg diazepam, anaesthetics) which give them longer half life

decreases VD of hydrophilic drugs (lithium, digoxin)

Question 14

what are the two types of drug metabolism?

Answer 14

hepatic

renal

Question 15

what is the problem with hepatic metabolism in elderly?

Answer 15

reduced liver function due to decreased liver size, blood flow and disease (eg CHF)

first pass metabolism reduced (eg propranolol)

in general, bio-transforming enzymes reduced in elderly

Question 16

what is the problem with renal metabolism in elderly?

Answer 16

lower GFR

serum creatinine not reliable measure

Question 17

what is the general principle of pharmacodynamics in elderly?

Answer 17

lower doses achieve same effect (common eg alcohol)

Question 18

what are drugs with narrow therapeutic index (must be checked regularly since helpful and harmful dose very close)?

Answer 18

theophylline 
warfarin 
lithium 
digoxin 
gentamicin 
vancomycin 
phenytoin 
cyclosporin 
carbamazepine 
levothyroxine

Question 19

what are common side effects of opioids in elderly?

Answer 19

constipation - begin lactulose or senna prophylactically

psychomotor function - falls and confusion

Question 20

what are common side effects of steroids in elderly?

Answer 20

osteoporosis

steroid induced diabetes

Question 21

what interferes with levothyroxine in elderly and therefore you should not take it at same time?

Answer 21

calcium

Question 22

what are common side effects of NSAIDs in elderly?

Answer 22

GI haemorrhage
decline in GFR
decreased effectiveness of diuretic and anti-hypertensive agents

give paracetamol in mild OA instead

Question 23

what is common side effect of amlodipine in elderly?

Answer 23

oedema

Question 24

if patient has been stable for over a year, what type of therapy should be tried?

Answer 24

combination

Question 25

what is beers criteria?

Answer 25

list of over 50 meds divided into 3 categories 1) always avoided (eg barbiturates, chlorpropamide) 2) potentially inappropriate (depends on co morbidity) 3) used with caution

Question 26

what is the STOPP tool?

Answer 26

screening tool of older peoples potentially inappropriate prescriptions

Question 27

what does STOPP say about loperamide or codeine phosphate?

Answer 27

do not give for diarrhoea of unknown cause - may exacerbate constipation or cause toxic megacolon in IBD

Question 28

what does STOPP say about prochlorperazine or metoclopramide?

Answer 28

do not give in those with parkinsons - exacerbates it

Question 29

what does STOPP say about stimulant laxatives?

Answer 29

do not give in those with intestinal obstruction - risk of bowel perforation

Question 30

what does STOPP say about beta blockers?

Answer 30

do not give in combo with verapamil - risk of heart block

Question 31

what does STOPP say about non cardioselective BB (propranolol, sotalol)?

Answer 31

do not give in those with COPD - risk of bronchospasm

Question 32

what does STOPP say about calcium channel blockers?

Answer 32

do not give in chronic constipation

Question 33

what does STOPP say about dipyridamole?

Answer 33

do not give as monotherapy unless intolerant to aspirin and clopidogrel

Question 34

what does STOPP say about atorvastatin?

Answer 34

do not give 80mg longer than 6 months post MI

Question 35

what is START tool?

Answer 35

screening tool to alert doctors to right treatments

Question 36

what does START say about PPIs?

Answer 36

use for GORD or stricture or >80yo on anti-platelet and SSRIs also use when aspirin and warfarin used in combo (rare)

Question 37

what does START say about fibre supplement?

Answer 37

use for chronic diverticular disease with constipation

Question 38

what does START say about antihypertensives?

Answer 38

use where systolic BP is consistently >160mmHg

Question 39

what does START say about ACE inhibitor?

Answer 39

use in chronic heart failure or post MI

Question 40

what does START say about warfarin / DOACs?

Answer 40

use in chronic AF and following diagnosis of DVT or pulmonary embolism if benefit outweighs risk of treatment

Question 41

adherence to drugs is usually not much worse than younger patients but what are specific issues with elderly compliance?

Answer 41

can they open pill container do they understand when and how to take it are they remembering

Question 42

what are short term side effects of anti-cholinergic drugs?

Answer 42

``` confusion hallucinations tachycardia blurred vision urinary retention constipation dizziness falls ```

Question 43

what is long term side effects of anti-cholinergic drugs?

Answer 43

increased risk of developing dementia

Question 44

which drugs cause postural hypotension?

Answer 44

alpha blocker for BPH and antihypertensive

Question 45

which drugs affect renal function?

Answer 45

antibiotic and ACE inhibitor

Question 46

which prescriptions should be time limited?

Answer 46

``` pain killers laxatives anti-depressants anxiolytics antipsychotics antihistamines antiemetics ```

Question 47

give 2 examples of prescriptions with no benefit?

Answer 47

OA back pain - paracetamol no better than placebo primary prevention in patients with short life expectancy = statins in advanced malignancy