Polypharmacy Flashcards
What is polypharmacy?
The use of 5 or more medications regardless of clinical appropriateness
What is appropriate polypharmacy?
The prescribing of multiple medications for managing complex or multiple medical conditions
What is problematic polypharmacy?
The prescription of 5 or more medications which have not been appropriately considered:
-medications not appropriate
-causing ADRs
-meds have harmful interactions
What are the 3 main causes reasons why patients have polypharmacy?
Multiple health conditions
Elderly
Acute hospital admission
Why are the elderly at increased risk of suffering Adverse drug reactions from polypharmacy?
Reduced drug absorption
Reduced renal function
Higher fat percentage
Reduced liver function
How is absorption of drugs in the elderly reduced?
Less gastric acid secretion and impaired intestine mobility
How does reduced renal function put elderly patients at a higher risk of suffering Adverse drug reactions due to polypharmacy?
Reduced renal function means impaired drug elimination in the urine
So levels of drug in the blood stay higher
Why is a higher fat percentage in the elderly a risk factor for making them more likely to suffer with adverse drug reactions due to polypharmacy?
The higher fat percentage means the fat soluble drugs accumulate more in the body and get to higher levels
Drugs that are fat soluble have a higher volume of distribution
Why does reduced liver function in the elderly put patients at an increased risk of suffering Adverse drug reactions due to polypharmacy?
Reduced functional reserve of the liver with age means the patients metabolism of drugs by the liver is reduced so they can accumulate higher
What are the main complications of polypharmacy?
ADRs
Deaths
Falls (Hip fractures)
Delirium
Lethargy
Depression
Increased risk of prescribing cascade
What is the prescribing cascade>
When an adverse drug reaction is misinterpreted as a new disease and a new drug is prescribed
Patient has hypertension, hypothyroidism and T2DM. Medications:
-amlodopine
-thyroxine
-metformin
Patient has a fall and has leg swelling so is also prescribed 40mg furosemide
Later presents to AE with fall and AKI:
What has happened here?
Prescribing cascade
Patients leg swelling likely to do with amlodopines common side effects
Loop diuretic given since Doctor must’ve thought patient was overloaded when she wasn’t
This vasodilator lead to fall and pre renal AKI
What 2 drugs commonly cause ankle oedema as a side effect?
Amlodopine
Doxazosin
What class of drug is doxazosin?
Alpha blocker
Why does amlodopine and doxazosin cause ankle odema?
They act as vasodilators
What medication that is an antipsychotic can cause Parkinsonism?
Haloperidol
What is the mechanism of action of haloperidol?
D2 receptor antagonist
What medications commonly precipitate gout?
Thiazide diuretics
Loop diuretics
Low dose aspirin
What is the management for gout?
NSAIDs for acute pain + Allopurinol to reduce levels of uric acid (long term)
Colchicine is used when NSAIDs are contraindicated
What are some anticholinergic effects of medications?
Dry eyes
Dry mouth
Fatigue/drowsiness
Constipation
Urinary retention
Palpitations
Feel hot (reduced sweat)
Blurred vision
Why do medications with an anticholinergic effects/burden lead to palpitations?
Increased heart rate happens since the regulation of heart rate is done by parasympathetics via the vagus nerve which signals to the heart via the neurotransmitter AcH
If theres an anticholinergic effects, the vagus nerve cant signal to the heart to keep its rate low, so heart rate increases
Why do drugs causing an anticholinergic effect cause blurred vision? (Not dry eyes)
Pupils dilated since sympathetics dilate the eye and the parasympathetic system cant communicate with the eye to constrict it
Ciliary muscles can’t contract meaning impaired accommodation reflex
What are some classes of drugs with a strong anticholinergic burden?
Antidepressants
Antiemetics
Antihistamines
Anti Muscarinics
Antiparkinsonian agents
Antipsychotics
Antispasmodics
Skeletal muscle relaxants
What are some antidepressants with a high anticholinergic burden?
Amitriptyline
Clomipramine
Imipramine
What are some antiemetics with a high anticholinergic burden?
Prochlorperazine
Promethazine
What are some antihistamines with a high anticholinergic burden?
Chlorpheniramine
Hydroxyzine
Promethazine
What are some anti Muscarinics with a high anticholinergic burden?
Oxybutynin
Solifenacin
Tolterodine
What are some antipsychotics with a high anticholinergic burden?
Chlorpromazine
Clozapine
Olanzapine
What are some antispasmodic with a high anticholinergic burden?
Atropine
What are the 2 criteria’s used to assess whether certain medications should be stopped or initiated?
Beers criteria
STOPP-START criteria
What is the STOPP-START criteria?
STOPP = Screening Tool of Older Persons Prescription criteria
START = Screening Tool to Alert doctors to Right Treatment
What is beers criteria?
Criteria of 5 groups of medications that should be avoided in older people and n the high risk drug to drug interactions
What is the general thought process when deciding whether a patients medications should change?
Discontinue unnecessary medications
Continue ADR as a cause for any new symtpoms
Consider a non pharmacological approach
Substitute drugs for safer drugs
Reduce doses
