Prescribing in the Elderly Flashcards
What are some common side effects of anticholinergics?
Confusion, dry mouth, constipation, blurred vision, urinary retention and orthostatic hypotension
What are some common side effects with tricyclic antidepressants
Confusion and unsteady gates
What are some side effects of digoxin?
Toxicity at what would typical be normal concentrations
What are som side effects of long acting benzodiazpines?
CNS toxicity
What are some common side effects with narcotics?
Confusion
What is meant by a prescribing cascade in the elderly?
Drug 1—–> adverse side effect
Drug 2—-> prescribed to treat ADR—-> New ADR
Drug 3—> prescribed to treat ADR……..
According to studies what are the most common conditions that cause D2D interactions
Type 2 diabetes
Depression
Heart failure
What contributes to polypharmacy?
No reviews with patients on a regular basis
Presumes the patient expects medications
Prescribes without sufficient investigation
Provides unclear instructions of how to use medication
What drugs cause the most admissions to hospital
NSAIDS
Diuretics
Warfarin
(anticholinergics and sedatives not ideal)
What are some common antimuscarinic drugs
Gastrointestinal antispasmotics Drugs for overactive bladder Tricyclic antidepressants Sedating antihstamines Antiemetics Antipsyhcotics Ranitidine Phenytoin Citalopram Fluoxetine Lithium Digoxin Temazepan
How does the absorption of drugs change in older people
Effect the rate of absorption, this may lead to a delay of onset
e.g. less saliva in mouht= less uptake for GTN
How does the distribution of drugs change in an elderly person?
Reduced muscle mass
Increased adipose tissue (Increased duration of action)
Reduced body water (increased serum levels)
Protein binding changes (decreased albumin, decreased serum levels)
Increased permeability across the blood brain barrier
How is the metabolism of drugs altered in elderly people
Hepatic metabolism is altered due to decreased liver mass and decreased liver blood flow
This leads to an increase in toxicity due to a decrease of metabolism and excretion
How does the excretion of drugs change with age?
Renal function decreases with age
How are pharmacodynamics different in elderly people?
Change in receptor binding
Decreased number of receptors
Altered translation of a receptor initiated cellular response
What are the principles of prescribing for old people?
Where possible be clear about the diagnosis to avoid prescribing due to an ADR
Consider whether drug therapy is the best therapeutic action
Lower doses are generally needed (start small and work up)
Think about what drug does
Review drugs
What problems can you run into when prescribing psychiatric drugs?
Sedative problems (falls, confusion)
Anti-psychotics (postural hypotension, stroke, confusion, movement disorders)
Anti-depressants- less effective, more dangerous
What problems can you run into when prescribing analgesic drugs?
More sensitive to effects, lower doses needed
Pethidine and tramadol may be less useful
NSAIDs- increased adverse effects e.g. renal imparement, GI bleeding
What problems can you run into when prescribing cardiovascular drugs?
Digoxin- increased toxicity, lower doses required
Diuretics- decreased peak effect, reduced clearance, abnormal U&E’s
Other issues around continence and mobility
What problems can you run into when prescribing antihypertensive drugs?
May have exaggerated effect son BP and HR
More likely to be issues with postural hypotension
ACE inhibitors often pro-drugs which may not be metabolised to the active form
Renal adverse effects
What problems can you run into when prescribing antibiotics?
Diarrhoea and c.diff Blood dyscrasias (altered mixture of blood cells) Delirium (quinolones) Seizures Renal impairment
