Drugs and Polypharmacy

Question 1

Define polypharmacy

Answer 1

Many drugs or inappropriate amount of drugs

Question 2

Common Adverse Drug Reactions (ADR)

Answer 2

Confusion
Dry mouth
Vision
Urinary retention

Question 3

DIGOXIN TOXICITY

Answer 3

Confusion
See paper patient

Normal serum concentrations

Question 4

Complications of polypharmacy

Answer 4

Falls

Mortality

Question 5

Over 50s 2-3x as many prescriptions

85y/o arond 8-9 + 2 OTC simultaneously

Answer 5

More acute and chronic illness
Increased visits to GP
Drugs to counteract side effects
Lack of continuity of care- discontinuation of prescription meds

Question 6

PRESCRIBING CASCADE

Answer 6

Prescribed drug leads to ADE; interpreted as new medical condition –> prescription of additional drug –> ADE–> additional prescription etc

Question 7

Hyperthyroidism- presenting signs and symptoms - Young patient

Answer 7

Tremor
Anxiety
Weight loss
Diarrhoea

Question 8

Hyperthyroidism presenting signs and symptoms- Elderly

Answer 8

Depression
Cognitive impairment
Atrial fibrillation, Heart Failure, Angina
Delirium
Muscle weakness

Question 9

Factors contributing to polypharamacy

Answer 9

Lack of regular med reviews
Presume patient expects medication
Prescribe without sufficient clinical investigation
Unclear/complex/incomplete instructions on how to take meds provided
No effort to simplify regimen
Ordering automatic refills
Lack of geri clinical pharmacology knowledge

Question 10

Worst drugs for ADR

Answer 10

NSAIDS
Diuretics
Warfarin
ACEi 
Antidepressants

Question 11

Effect of physiological changes on Absorption

Answer 11

Alters rate but not extent
eg, reduced saliva production, reduced GTN absorption

Exception - levodopa in Parkinsonism - lower enzyme levels in elderly - increased absorption; higher peak plasma level, shorter time to peak

Question 12

What changes affect distribution?

Answer 12

Body composition - muscle mass, water (digoxin), adipose tissue (fat soluble drugs- diazepam)
Protein binding changes - albumin decrease, increase serum levels
Permeability across blood-brain-barrier

Question 13

Factors affecting hepatic metabolism

Answer 13

Reduced mass
Reduced blood flow

Leads to toxicity
Increased availability of some drugs eg propanolol
Decreased bioavailability of pro-drugs- enalapril (activated once passed through liver)

Question 14

Excretion

Answer 14

Decreased renal function
Reduced clearance
Increased half life of drugs
–> Toxicity

Question 15

Pharmacodynamics

Answer 15

change in receptor binding,
decrease in receptor number,
altered translation of a receptor initiated cellular response into a biochemical reaction

Question 16

Beer’s Criteria

Answer 16

List of inappropriate drugs to prescribe elderly

Question 17

START STOPP Criteria

Answer 17

Optimisation

Question 18

Deprescribing

Answer 18

To reduce, substitute or discontinue a drug

Question 19

Reasons for deprescribing

Answer 19

Adverse drug reaction
Drug-drug interaction
Drug-disease interaction
Better alternative
Not effective
Not indicated
Not evidence-based
Minimise polypharmacy

Question 20

Adverse effects Psychiatric drugs

Answer 20

Sedatives - benzodiazepines; falls and confusion
Anti-psychotics - Postural hypotension, stroke, confusion, movement disorders
Anti-depressants; ineffective in treating agitation –> more dangerous?

Question 21

Adverse effects Anlagesia

Answer 21

Opioids - more sensitive to effects, lower doses needed

NSAIDs- Renal impairment, GI bleeding

Question 22

Adverse effects Cardiovascular

Digoxin

Answer 22

Increased toxicity, lower doses needed

Narrow therapeutic index

Question 23

Adverse effects Cardiovascular

Diuretics

Answer 23

Decreased peak effect, reduced clearance - abnormal U&Es
Incontinence and mobility need considered
Inappropriate indication - swollen legs

Question 24

Adverse effects Cardiovascular

Anti Hypertensives

Answer 24

May have exaggerated effects on BP and HR
More likely to be issues with postural hypotension
ACE inhibitors often pro-drugs which may not be metabolised to the active form
Renal adverse effects

Question 25

Adverse effects Cardiovascular

Anticoagulants

Answer 25

More sensitive to warfarin
Greater risk from warfarin - GI Bleeding, falls
Decreased requirements per decade of life (clotting factors)

Question 26

Antibiotics Adverse Effects

Answer 26

Diarrhoea and c. diff infection
Blood dyscrasias (trimethoprim, co-trimoxazole)
Delirium (quinolones)
Seizures
Renal impairment (aminoglycosides)