Pharmacology/prescribing

Question 1

Why do lipiphilic drugs such as anaesthetics/diazepam have a longer half life in older people?

Answer 1

Greater volume of distribution due to increased fat:muscle ratio

Question 2

Why is GFR generally reduced in the elderly?

Answer 2

Decreased size, lower renal blood flow

Question 3

What is the drawback of the MDRD equation for older people?

Answer 3

Older people have lower muscle mass, hence MDRD tends to over-estimate eGFR

Question 4

What happens to the therapeutic index for drugs such as warfarin, lithium in older people?

Answer 4

Becomes narrow

Question 5

How is the therapeutic index calculated?

Answer 5

LD50/ED50 (the median lethal dose over the median effective dose)

Question 6

Erythromycin and clarithromycin are examples of…

Answer 6

Macrolide antibiotics

Question 7

Interactions of macrolides? (2)

Answer 7

Theophylline

Statins

Question 8

Key warfarin interactions (increase the INR) (7)

Answer 8

NSAIDs
Cimetidine
SSRIs
Various antibiotics (metronidazole, macrolides, tetracyclines)
Antiplatelets
Cranberry juice
Acute alcohol intoxication

Question 9

What is the most potent enzyme inducer that reduces the INR of a person on warfarin?

Answer 9

Rifampicin

Question 10

The hypoglycaemic effect of sulfonylureas is increased by which class of drug?

Answer 10

ACE inhibitors

Question 11

Clopidogrel and PPI- effect?

Answer 11

Inhibits the effect of clopidogrel

Question 12

Rare adverse effect of chloramphenicol?

Answer 12

Bone marrow suppression

Question 13

What are the four drugs most commonly associated with adverse reactions in the elderly?

Answer 13

Warfarin
Digoxin
Insulin
Benzos

Question 14

Problems with NSAIDs particularly in older people?

Answer 14

GI bleed risk, decline GFR, decreased effectiveness of anti-hypertensives and diuretics

Question 15

Adverse effects of using antibiotics in older people without clinical evidence of infection?

Answer 15

C diff

Resistance

Question 16

Why is hypovolaemia in response to diuretics more likely in older people?

Answer 16

Blunted thirst response

Question 17

Examples of drug-disease interactions? (2)

Answer 17

Drugs with anticholinergic properties- precipitate urinary retention in men with prostatic hyertrophy
Benzodiazepines can precipitate delirium in a patient with dementia

Question 18

What is the danger of oral hypoglycaemics in older patients? How can this be prevented?

Answer 18

Increased susceptibility to hypos, and decreased awareness of them. Avoid using longer-acting formulations, start low and go slow

Question 19

Uncontrolled hypertension + renal bruit…?

Answer 19

Renal artery stenosis

Question 20

Which commonly-prescribed class of drugs should be used with extreme caution in renal artery stenosis?

Answer 20

ACE inhibitors- precipitate renal failure

Question 21

Monitoring for older patients being started on ACE inhibitors?

Answer 21

Baseline eGFR and electrolytes, before starting and before increasing doses

Question 22

Co-morbidity which increases risk of ACE inhibitor-induced hypotension?

Answer 22

Aortic valve stenosis

Question 23

Which electrolyte disturbance is a side effect of ACE inhibitor therapy, and concurrent prescription of which drugs enhances this risk?

Answer 23

Hyperkalaemia

Potassium sparing diuretics e.g. spironolactone

Question 24

When can the tendency to hyperkalaemia of ACE inhibitors be useful?

Answer 24

When also on a potassium-losing diuretic, e.g. furosemide or bendroflumothiazide

Question 25

Amiodarone interactions? (2)

Answer 25

Increases the effect of warfarin | Increased myopathy risk with statins

Question 26

Adverse effects of amiodarone? (7)

Answer 26

``` Deranged TFTs in either direction Nausea and anorexia Photosensitivity Corneal microdeposits (reversible) Pulmonary fibrosis/alveolitis/pneumonitis Peripheral neuropathy Deranged LFTs ```

Question 27

Indications for amiodarone?

Answer 27

Rate control, prevention of supraventricular tachyarrythimias (e.g. fast AF), prevention of paroxysmal ventricular tachyarrythmias

Question 28

Adverse effects of NSAIDs in older people? (3)

Answer 28

Fluid retention Renal toxicity- risk of acute tubular necrosis Peptic ulceration --> GI bleeding

Question 29

What are the consequences of fluid retention in older people? (3)

Answer 29

Worsening hypertension Worsening heart failure Ankle swelling

Question 30

Which group of drugs should you avoid co-prescribing NSAIDs with?

Answer 30

ACE inhibitors- increases the likelihood of renal toxicity

Question 31

Guidance for NSAID use in older people?

Answer 31

Use with extreme caution, avoid altogether in the very frail Short periods, low dose, moderate potency Avoid using two together (including aspirin)

Question 32

What should you consider co-prescribing with NSAIDs in an older patient?

Answer 32

omeprazole

Question 33

Potential issues with opioid analgesia in older people?

Answer 33

``` Constipation Nausea and vomiting Confusion Drowsiness Toxicity (respiratory depression) ```

Question 34

Conditions for which oral steroids are commonly prescribed in older patients? (4)

Answer 34

COPD exacerbations Colitis Polymyalgia rheumatica Rheumatoid arthritis

Question 35

Bone protection for older patients on long-term (i.e. more than 2 weeks) steroids? (2)

Answer 35

Daily calcium and vitamin D | Bisphosphonate (daily/weekly)

Question 36

Which basic clinical measurements should be monitored regularly when patients are on long-term steroids?

Answer 36

Blood glucose | Blood pressure

Question 37

Why does increased blood pressure occur when treated with prednisolone?

Answer 37

Mineralocorticoid effect

Question 38

Skin changes with steroid use? (4)

Answer 38

Purpura Bruising Skin thinning and fragility Striae

Question 39

Pattern of myopathy with steroid use?

Answer 39

Mostly proximal, causing problems such as rising from chairs

Question 40

Why should steroids be given mane if possible?

Answer 40

Can cause acute confusion and sleep disturbance

Question 41

Infections which are particularly common in long-term steroids?

Answer 41

Oral and genital candidiasis

Question 42

Steroid rules for acute illness?

Answer 42

Double the usual oral dose; replace with IM hydrocortisone if NBM

Question 43

Which condition can be "masked" by steroid use?

Answer 43

Peritonitis and/or perforation

Question 44

Absolute indications for warfarin? (3)

Answer 44

PE DVT Heart valve replacement

Question 45

Relative indication for warfarin?

Answer 45

Stroke prophylaxis in AF