Prescribing in the Elderly Flashcards
Acidic drugs require an acidic environment for absorption
Basic drugs require a basic environment for absorption
just info
Name an acidic drug
Phenytoin
Aspirin
Penicillins
Name a basic drug
Diazepam
Morphine
Pethidine
What binds to acidic drugs?
Albumin (basic)
What binds to basic drugs?
Alpha-1 acid glycoprotein (acidic)
A-1 AG
Do the elderly have:
High/low Albumin
High/low A1-AG?
Low albumin
High A-1 AG
Why do lipophylilc drugs have a longer half life in the elderly?
Elderly have a higher fat to muscle mass ratio
Why do hydrophilic drugs have a lower distribution in the elderly?
Elderly have decreased body water
Name a lipophylic drug
Diazepam
Anaesthetics
Name a hydrophilic drug
Lithium
Digoxin
Where does first pass metabolism occur?
Gut + LIVER
Why is first pass metabolism reduced in the elderly?
Decreased liver size, blood flow and possible liver disease
What does first pass metabolism do?
Greatly reduces drug concentration before it enters circulation
Generally, lower doses achieve the same effect in the elderly but some drug’s effects are decreased. What drugs might these be?
Beta blockers + HR
Name some drugs with narrow therapeutic index
Warfarin Lithium Digoxin Theophyllin Gentamicin Vancomycin Phenytoin Cyclosporin Carbamazepine Levothyroxine
What is the volume of distribution?
Theoretical volume if all of the drug you give to a patient was completely absorbed and distributed within the plasma
Why are lipophilic drugs dangerous?
Sit in fatty tissue for a long time
any period of cachexia then the drug will be released as it breaks down
What should you give to a an elderly patient in conjunction with opioids?
lactulose or senna
If a patient is gonna be on steroids long term, what should you give them in addition?
Osteoporosis prevention
be aware of steroid induced diabetes
What interferes with absorption of levothyroxine?
Calcium
What drug is just as effective as NSAIDs in mild OA?
Paracetamol
Why are opioids and benzos avoided in the elderly?
Impair psychomotor function
Falls and confusion
Why should you avoid giving lots of antibiotics in the elderly?
Resistance and C.diff
What is BEERs criteria?
Notifies drugs that are potentially inappropriate to give to the elderly
Why should you stop prescribing loperamide or codeine phosphate in the elderly?
For treatment of diarrhoea - delays diagnosis
May exacerbate constipation
May precipitate toxic megacolon and IBD
Why should you avoid prescribing metoclopramide and prochlorperazine in Parkinson’s?
May exacerbate it
Why should you not prescribe stimulant laxatives in patients with intestinal obstruction (Senna)?
Risk of bowel perforation
Why should you stop beta blockers in combination with verapamil?
Risk of symptomatic heart block
Why should you not prescribe a non-cardioselective beta blocker in patients with COPD?
Risk of bronchospasm
What drug should you start in chronic heart failure/post MI?
ACEi
What drug should you start in chronic AF?
Warfarin
