Medicine use in older adults Flashcards
What is overprescribing
What are the problems associated with this
Being prescribed a large no of different medications which may result in many AEs.
-some may not be beneficial or never reviewed
Older adults are at increased risk of AEs
What is frailty?
How can you measure frailty
LTC with acute deterioration
Reduced ability to rebound from external stressors => frequent hospital admissions with geriatric syndromes and increased susceptibility to AEs
Rockwood Clinical Frailty Scale
-judged on ADLs, mobility
E Frailty Index
- uses primary care data to identify older adults with varying degrees of frailty
- predicts outcomes for mortality, hospitalisation, nursing home admissions
Describe the impact of ageing and frailty on medicine use
Changes in physiology => changes in drug handling
Reduced mobility, functional, sensory, cognitive impairments
Multiple prescribers, polypharmacy and lack of communication between them => increased AE
Need to consider access to medicines, adherence and barriers to it
Describe the physiology behind the ageing process
Progressive loss of functional capacities of most organ systems
Changes in response to receptor stimulation
Decrease in homeostatic/counter regulatory mechanisms
Loss of body water, muscle and increase in body fat
How does drug absorption change with age
How does drug distribution change with age
Decreased gastric emptying and secretions, changes in gastric pH
-decreased absorption
Increased in body fat => increased Vd for fat soluble drugs increases T1/2 => toxicity
-diazepam leads to prolonged sedation => falls
Decrease in body water => decrease Vd for water soluble drugs increases conc => toxicity
- even more impactful if it has a narrow therapeutic index
- lithium, digoxin => confusion
Decreased serum albumin => free drug conc => toxicity
- due to frailty, malnutrition, post surgery, renal/hepatic impairment
- warfarin, phenytoin, diazepam
How does drug metabolism change with age
How does drug elimination change with age
Impaired 1st pass metabolism via portal vein => increased bioavailability, toxicity
-due to decreased hepatic flow, size, liver enzymes
Will need to consider LFTs to check liver function, can titrate accordingly
Decreased renal mass, blood flow, function => failure to excrete => accummulation and toxicity
Drugs accumulate slowly in chronic use, signs of toxicity may build up very very slowly
On the other hand, thiazides don’t work in renal dysfunction
Always check eGFR before prescribing
-if eGFR U60 => reduce or temporarily stop nephrotoxic, renally excreted drugs
Initiate with low dose and titrate upwards
What are the main common drugs that are metabolised and eliminated renally
Aminoglycosides
NSAIDs, ACEi, ARBs
Metformin
Why are older adults at increased risk of
- falls, postural hypotension
- confusion
- hypothermia
- constipation, urinary incontinence
Blunting of reflex tachycardia, postural control => falls, PHT
Structural, neurochemical changes in CNS => confusion
Impaired thermoregulation => hypothermia
Reduced visceral muscle function (reduced ACh, D) => constipation, urinary incontinence
What red flag drugs are most commonly associated with ADRs
Which medications are implicated in hospital admissions
ADRs
-opioids => drowsiness, falls due to increased CNS sensitivity
- NSAIDs => PE formation (PGI inhibition), increased GI bleed risk
- anticholinergics => can’t see, pee, sweat, shit
- BZ => increased prolonged sedative effects due to increased CNS sensitivity
- CV, CNS, MSK drugs
- warfarin => increased INR due to increased receptor sensitivity
- digoxin => irregular HR
- insulin => may forget to take it leading to HHS, DKA
- diuretic => increased sensitivity leading to dehydration
What are the most common ADRs
What are the key features
Increases with age, no of drugs
Most are dose dependent, predictable, preventable but most are vague and non specific
Confusion, delirium, falls
Anticholinergic symptoms Can't pee Can't see Can't shit Can't sweat
What is a prescribing cascade
Misinterpretation of ADRs as new medical conditions leading to subsequent inappropriate prescriptions
What are some reasons for unintentional non adherence
What are some reasons for intentional non adherence
Frailty, functional decline Poor mobility, coordination, dexterity Swallowing difficulties Sensory, cognitive impairments Reduced concentration, learning, understanding Complex dosing Poor social support
Low necessity beliefs, high concerns
What is polypharmacy
6+ prescribed medicines that is more than clinically required
Linked to poor patient outcomes, increased ADRs, hospital admissions, costs and poor adherence
How would you address polypharmacy
Deprescribing taking into account the patient’s physical functioning, comorbidities, preferences, lifestyle, risks and benefits
Can use STOPP/START tool
