Prescribing in the Older Patient Flashcards
What are common iatrogenic drug problems?
Confusion, dry mouth, constipation, blurred vision, urinary retention, orthostatic hypotension with anticholindergics
Confusion and unsteady gait with tricyclics
Digoxin toxicity with normal serum concentrations
CNS toxicity with long-acting benxodiazepines
Confusion with narcotics
How do ADRs present in elderly?
Like “growing old”
Unsteadiness Dizziness Confusion Nervousness Fatigue Insomnia Drowsiness Falls Depression Incontinence
Why can patients end up on so many drugs after an ADE?
Often ADEs are interpreted as new medical conditions
What are the ‘worst’ drugs in polypharmacy?
NSAIDs Diuretics Warfarin ACEIs Antidepressants B-blockers Opiates Digoxin Prednisolone Clopidogrel
What drugs cause most adverse events?
Anticholinergics
Sedatives
How can absorption of drugs be affected?
Physiological changes can effect rate but generally not the extent of absorption from GI tract
Eg. reduction in saliva production may result in a reduction in rate of absorption of buccally administered drugs
How can distribution of drugs be affected?
Body composition changes
- reduced muscle mass
- increased adipose tissue
- reduced body water
Protein binding changes
- decreased albumin
Increased permeability across blood-brain barrier
How can metabolism of drugs be affected?
Hepatic metabolism affected by;
- decreased liver mass
- decreased liver blood flow
Consequences
- toxicity due to reduced metabolism/excretion
- reduced first pass metabolism
How can excretion of drugs be affected?
Renal function decreases with age
Reduces clearance and increases half-life of many drugs, leading to toxicity
How can pharmacodynamics affect drugs?
Increased sensitivity to particular medicines
Due to
- change in receptor binding
- decrease in receptor binding
- altered translation of a receptor initiated cellular response into a biochem reaction
Describe deprescribing
To reduce, substitute or discontinue a drug
WHY?
- ADR
- drug-drug interaction
- drug-disease interaction
- better alternative
- not effective
- not indicated
- not evidence-based
- minimise polypharmacy
Describe the treatment of psychiatric issues in elderly
Care with treating ‘agitation’
Sedatives problematic
- increased effects of benzodiazepines; falls, confusion
Anti-psychotics
- increased adverse effects; postural hypotension, stroke, confusion, movement disorders
Anti-depressants; less effective, more dangerous
Describe issues in prescribing opioids to elderly patients
More sensitive to effects, lower doses needed
Pethidine and tramadol may be less useful
Describe issues in prescribing NSAIDs to elderly patients
Increased adverse effects
- renal impairment
- GI bleeding
Describe issues in prescribing digoxin to elderly patients
Increased toxicity
Lower doses needed
