Elderly- Polypharmacy Flashcards
What are examples of ADR presentations that could be confused with normal ageing?
- Unsteady
- Dizzy
- Confusion
- Falls
- Depression
- Incontinence
What is the process of the prescribing cascade?
- Given a drug that causes an ADR
- ADR interpreted as a new condition
- Given another drug to treat the ADR
What are the 2 most dangerous drugs for polypharmacy?
Sedatives
Anticholinergics
How is absorption of a drug affected by age?
The rate of absorption decreases but the extent of absorption doesn’t
How is the distribution of a drug affected as age increases?
Decreased albumin
Increased adipose fat
Decreased water content
How does the decrease in albumin affect the distribution of a drug?
Less protein binding
Greater serum conc of acidic drugs e.g. furosemide
How does the increase in adipose tissue affect the distribution of a drug?
Fat soluble drugs
Increased volume of distribution, rate of absorption and half life
How does the decrease in water content affect the distribution of a drug?
Water soluble drugs
Decreased volume of distribution, rate of absorption and half life
How is the metabolism of a drug affected as age increases?
There is decreased hepatic metabolism
What does a decrease in hepatic metabolism result in a decrease of?
- Decreased liver mass and blood flow to the liver
* Decreased first pass metabolism
What does a decrease in hepatic metabolism result in an increase of?
- Increased toxicity of drugs metabolised in the liver
* Increased availability of Pro-drugs
How is the excretion of a drug affected as age increases?
Renal function decreases
• Reduced clearance- increased half life
• Toxicity
What pharmacodynamic changes are there with increasing age?
- Changes in receptor binding, number, and effect
- Increased sedation on diazepam
- Increased anti-coagulation on warfarin
What are the side-effects of benzodiazepines in the elderly?
Falls
Confusion
What are the side-effects of anti-psychotics in the elderly?
Postural hypotension
Stroke
Confusion
Movement disorders
What is the problem with anti-depressants in the elderly?
They are more dangerous and less effective
How does the dose of digoxin and opioids need to be changed?
Decrease the dose- there is increased toxicity
What are the possible side effects of NSAID’s in the elderly?
Renal impairment
GI bleeding
What are the possible side-effects of antibiotics in the elderly?
- Increased adverse effects
- Diarrhoea and c. diff infection
- Blood dyscrasias (trimethoprim, co-trimoxazole)
- Delirium (quinolones)
- Seizures
- Renal impairment (aminoglycosides)
What are the possible side-effects of warfarin in the elderly?
- More sensitive to warfarin
- Greater risk from warfarin i.e. GI bleeding, falls
