Drugs + Polypharmacy Flashcards
How is absorption affected in elderly
Rate affected but not extent
How is distribution affected
Reduced muscle mass
Increased adipose so increased fat soluble drugs
Reduced body water so reduced water soluble drugs
Decreased albumin so increased free drugs
Increased permeability across BBB
How is metabolism affected
Decreased hepatic metabolism as decreased liver mass and blood flow
So drugs metabolised slower and stay in body
How is excretion affected
Renal function decreases so reduced clearance and increased half life
If renal affected use hepatic metabolised drugs etc
What are the pharmacodynamic effects due to age
Increased sensitivity to medicine - diazepam and warfarin have increased effects
Change in binding
Decreased receptor numbers so different effects
Altered translation of cellular response so increased
What help is there for drug dosage in elderly
BNF Schedule of product characterisitcs Beer's criteria = inappropriate drugs START-STOP NHS Scotland Polypharmacy Guidance
Issues with anti-psychotics
Hypotension
Stroke / TIA
Confusion
Movement disorder - Parkinsonism as dopamine antagonist
Issues with sedatives (Benz anxiolytic)
Falls
Postural hypo
Confusion
ADR
Issues with opioids
More sensitive so lower dose Constipation - prescribe laxative, may precipitate delerium Renal Confusion Falls Hallucination Resp depression
Issues with NSAID / steroid
Increased adverse
Renal + bleeding
Peptic ulcer
CI asthma / renal failure
Not recommended >2 weeks without gastric protection / not recommended >65
Issues with digoxin
Increased toxicity so lower dose
Arrhythmia
Vomiting
Issues with diuretics
Reduced clearance so abnormal U+E's Continence issue Hypokalaemia Falls Postural hypo Often used inappropriately e.g. swollen legs (should bel last resort)
Issues with anti-hypertensives
Increased effect on BP and HR
Postural hypotension
Falls and mortality
Renal failure
Issues with anti-coagulant
More sensitive to warfarin
Greater risk of bleeding and falls
Issues with antibiotics
Increased adverse effects Delerium Seizure Renal C.diff Deaf + renal in gentamicin
What are drugs commonly involved in ADR
NSAID DIuretic Warfarin ACEI Anti-depressant BB Opiates Digoxin Prednisolone Clopidogrel Anticholinergic + sedatives = major
How does ADR in elderly present
Often 'growing old' symptoms so more drugs prescribed Falls Delerium Dehydration Incontinence Depression
Why polypharmacy?
Acute and chronic disease No review Different doctors Drugs to counteract side effects ADR treated
Issues with anticholinergics
Postural hypo / dizzy Falls Confusion and delirium Cognition Retention - urinary and bowel so CI if BPE Constipation Blurred vision Tachycardia Dry eyes and dry mouth as cholinergic receptors here
CI BPE / glaucoma/. MG
Issues with cholinesterase inhibitors - used in dementia
N+V+D Fatique Insomnia Cramps Headache Syncope / fall
Common drugs in the elderly
Diuretics Analgesia Hypnotics / sedatives / anxiolytics Anti-hypertensive Anti-psychotics Anti-rheumatic BB Digoxin
Why ADR important in elderly
Altered pharmacodynamics / kinetics Increased sensitivity Potential drug interactions Polypharmacy Compliance - may take more if ill as think will help or less as forget
What should you do when prescribing
As few as necessary Review Decreased dose and go slow Close monitoring Alert if new symptoms when prescribed Think if develop symptoms and just started on drugs
What issue with hypoglycaemia
DOn’t need as tight control in elderly of DM as complications already arisen
Examples of anti-cholinergic drugs
Anti-muscarininc Furosemide Anti-histamine CLozapine Warfarin Ranitidine TCA - amitriptyline (confusion)
What should you do with drugs
STOP if don’t need / likely to be causing delirium
What does gentamicin cause
Renal failure
Hearing loss
What is polypharmacy
> 4 drugs
What should you always think
Is drug renal or liver cleared
What drugs cause postural hypo
Anti-hypertensive- ACEI/ BB Diuretic Nitrates Hypoglycaemia agent Anti-cholinergic Anti-depressant L-dopa
What drugs cause falls for other reason
Sedative / benzo Anti-psychotic Opiates Anti-convulsant Digoxin
What are very dangerous drugs in the elderly
Ibuprofen
Ramipril
