Drugs and Polypharmacy Flashcards
What is polypharmacy?
No exact definition.
Often classes as 5 or more drugs.
What are common adverse drug reactions?
confusion dry mouth constipation blurred vision urinary retention orthostatic hypotension falls delirium dehydration incontinence depression
What are common adverse drug reactions?
confusion dry mouth constipation blurred vision urinary retention orthostatic hypotension falls delirium dehydration incontinence depression fatigue nervousness insomnia unsteadiness
What happens to absorption with increasing age?
The EXTENT of absorption is not affected. The RATE of absorption is slower. GI transit time is increased so drugs take longer to work.
**Exemption is Parkinson’s - so lower doses Is needed because their speed of absorption is increased.
What happens to distribution with increasing age?
Increased adipose tissue
Decreased protein
Decreased body water
Reduced endothelial function
*Fat soluble drugs - Half life is increased
*Water soluble drugs - serum levels will be higher
*Protein - higher bioavailability of active drug (because binding to albumin usually renders the drug inactive)
Blood -brain barrier - becomes more leaky.
What happens to metabolism with increased age?
Liver mass and blood flow decreases = Reduced first pass metabolism and higher bioavailability of drugs.
Often leads to toxicity.
What happens to excretion as you increase in age?
Reduced renal clearance and increased half life.
Often leads to toxicity.
Have to spread drug doses out more.
What should be done to warfarin?
Requirement should be decreased by 10% every year. Because as we age the liver starts to produce less clotting factors.
Why is there an increased sensitivity to some medicines as we grow older?
Reduced protein = reduced receptor binders
What should be remembered about prescribing to the elderly?
Lower doses (or reduced frequency of administration) is usually needed.
Start at the lowest dose and titrate up.
Which drugs produce the most adverse events?
Anticholinergics
Sedatives
