Pharmacology and older people Flashcards
What is polympharmacy?
- Taking 5 or more regular medications
- ‘Appropriate polympharmacy’ or ‘problematic polypharmacy’
- Polypharmacy on the rise so more important now
- > 16% of over 65s taking >10 meds
How many medications to elderly patients take, on average, in:
- Hospital
- Nursing homes
- Hospital: 6 regular meds, +3 on discharge
- Nursing homes: 8 regular meds
What is an important issue to highlight about drug trials?
Trials often don’t include frail, elderly patients with co-morbidities - they’re done on younger, healthier patients.
Each additional medication increases the risk of errors. What problems have adverse drug reactons caused?
- 6.5% of hospital admissions (inc to 10% in over 65s)
- Median length of stay 8 days
- 0.15% mortality rate
What are the commonest implicated medications, when it comes to adverse drug reactions?
- Aspirin, NSAIDs, anticoagulants
- Diuretics
- Diabetic drugs
What will a patient with an adverse drug reaction from diuretics present with?
Hyponatraemia (low sodium)
What will a patient with an adverse drug reaction from diabetic drugs present with?
Hypoglycaemia
In terms of routes of administration, why is oral delivery of drugs a problem in the elderly? Give examples + solutions
- Dysphagia more common in elderly
- Parkinson’s disease -> consider patches
- Stroke -> consider rectal aspirin
- Change to liquid medications
What are the problems with IV delivery of drugs? Give solutions
- Challenging due to hyperactive delirium
- Intermittent fluid boluses (throughout day)
- Once daily IV antibiotics
Why might compliance be difficult and what considerations should be taken into account?
- Compliance hard with cognitive impairment
- Consider topical drugs for memory
- Conert medication to intra-muscular or subcutaneous
What physiological changes occur in absorption of drugs with elderly patients?
- Decreased gastric acid production
- Reduced splanchnic blood flow
What disease states alter absorption of drugs?
- Inflammatory bowel disease
- Coeliac disease
Co-prescription of which drugs alter absorption?
- Iron
- Antacids
- Omeprazole
What changes occur in an elderly patients body distribution/composition?
- Reduction in lean body mass
- Relative increase in body fat
- Decrease in total body water
Due to the relative increase in body fat with elderly patients, what does this mean for water soluble drugs?
Since drug distribution depends largely on body composition these changes result in reduced volume of distribution of water soluble drugs.
So water soluble drugs have higher serum levels, so the following changes are made to drugs such as:
- Gentamicin -> lower dosing regime
- Digoxin -> lower loading dose
How do albumin levels change in elderly patients and what affect will this have on drug distribution?
Serum albumin levels have been reported to reduce with age but this may reflect poor nutrition, chronic illness or debility rather than the effects of the ageing process itself.
- likely to affect drug binding -> inc in free drug conc
- may have clinical relevance
What changes occur in elderly patients affecting metabolism?
- Reduced liver mass + blood flow:
- -> first pass metabolism reduced
- -> drugs eliminated in the liver more likely to accumulate - morphine
- More likely to be co-prescribed enzyme inhibitors + inducers
Enzyme inhibitors are those which inhibit cytochrome P450 and therefore impair metabolism. List some enzyme inhibitors (SICKFACES.COM)
- Sodium valproate
- Isoniazid
- Cimedtidine
- Ketoconazole
- Fluconazole
- Alcohol (binge drinking)
- Chloramphenicol
- Erythromycin
- Sulfonamides
- Ciprofloxacin
- Omeprazole
- Metronidazole
Enzyme inducers are those which induce cytochrome P450 and therefore encourage metabolism. List some enzyme inducers (CRAP GPS)
- Carbamezapine
- Rifampin
- Alcohol
- Phenytoin
- Griseofulvin
- Phenobarbital
- Sulphonylureas
What renal changes occur in elderly patients, and how does this affect elimination?
- Multifactorial reduction in eGFR
- -> accumulation of water soluble medications
- eg. gentamicin, lithium, digoxin, NSAIDs
In terms of pharmacodynamic implications of ageing, what are drugs for high blood pressure likely to do to elderly patients? Why is this?
Drugs for BP will have a greater effect resulting in postural hypotension. Due to media in blood vessels getting stiffer, get hypertension but then when patient stands up, they have lost their elastic recoil so BP drops suddenly.
Therefore we set higher targets of BP in elderly than in younger people.
What is meant by chonotropic medications and how do elderly patients response to them?
- Drugs to increase HR
- Reduced response in elderly patients
What type of drugs are psychotropic medications?
Anti-dopaminergic drugs
What effect do antipsychotics have in the elderly?
- Increased EPSE (extrapyramidal symptoms)
- > eg. dystonia, dyskinesia, akathisia
- Never give (LB) dementia patients antipsychotics
What impact do anticholinergics have on elderly patients?
Increased delirium
What will benzodiazepines (eg. diazepam) induce in elderly patients?
Increased sedation at lower dose -> risk factor for falls + ADRs
Which class of drugs have a greater vitamin K inhibition in elderly patients? Example?
Anticoagulants eg. warfarin
What are the factors hindering safe prescribing in the elderly?
- Heterogenic comorbid patient group
- Increasing prevalence of polypharmacy
- Limited applicable evidence + trials in this cohort
- High incidence of adverse drug reactions
- Unpredictable pharmacokinetics complicated by polypharm
- Compliance + cognitive impairment
- Healthy ageing vs frailty
What is the advice for prescribing in the elderly?
- Focus on patient QOL, not disease specific prescribing
- Include drug side effects in the differential diagnosis
- Start slow + low
- Try not to treat drug side effects with extra drugs
- Avoid co-prescribing antagonistic drugs
- Consider non-pharmacological options or other routes
- Avoid starting 2 drugs simultaneously
What are the indicators that a medication review is required?
- Adverse drug reaction
- > 10 regular medications
- Those at falls risk (>4 meds)
- Markers of frailty
- New palliative diagnosis
What are the validated tools to review polypharmacy?
- Beer’s Criteria
- STOPP / START criteria
- Deprescribing.org
- Anticholinergic risk scale
What % of prescribed medications are not taken?
50% !!
PMH (9)
What are the reasons for low compliance in the elderly?
- Patient factors: cognitive impairment, sensory deficits, lack of caregiver
- Medication factors: polypharmacy, poor labelling, side effects
- Healthcare factors: patient education, regular follow up, patient involvement
What techniques can be implemented to aid compliance?
- Educate + empower patients
- Simplify drug regimes
- Discuss regimes with carers
- Inform of early side effects
- Encourage use of drug diaries
- Use large print on bottles + easy to open
What are monitored dosage systems?
- Patient given tray with different organised medications
- Often in nursing homes
- Don’t aid compliance as patient doesn’t have to take them
- Can aid carers that are giving meds
- Aids specific groups of people
What is meant by ‘telemedicine’?
- Electronic devices to support people
- Alarms, timers, reminders to take meds
What is covert administration?
- The administration of any drug or medical treatment to a patient without their knowledge, in a disguised or deceptive form
- Family support, meetings, signed documentation
- Aimed for patients w/ cognitive impairment (eg dementia)
- In nursing homes
