Polypharmacy Flashcards
Meanings of polypharmacy?
Multiple definitions :
▫ Too many tablets
▫ “Unnecessary drug use”
▫ “Medication use without indication”
Prevalence of polypharmacy?
Common – 20% of those >70 take 5 or more drugs
• Increasing – mean no of items prescribed to over 60’s
per year has doubled (21.2 to 40.8) since 2000
• Inappropriate – up to 40% are inappropriate prescriptions
• Associated with bad outcomes – readmissions, falls, adverse drug events, mortality, length of stay, cost
What can lead to polypharmacy?
- Multiple co-morbidities
- Guidelines/NICE
- Lack of evidence base
- Infrequent review
- Poor communication
- Undetected non-adherence
What is pharmacokinetics?
ADME
How does ageing affect Absorption?
- Decrease gut motility thus potentially longer intestinal transit time
- Decrease GI blood flow
- Increase gastric pH
How does ageing affect Distribution?
- Decrease body water
- Decrease lean body mass
- Increase fat stores
- Decrease plasma protein (albumin)
Hydrophillic drugs have decreased Vd.
How does ageing affect Metabolism?
- Decrease in hepatic mass and blood flow
- Decrease in first pass metabolism leading to increase in bioavailability
- Multi-drug therapy leading to interactions
How does ageing affect Excretion?
- Renal function is significantly reduced
- Decrease blood flow to the kidneys
- Decrease number of functional nephrons
- Decrease tubular secretion
- Decrease kidney size
What is pharmacodynamics?
- Study of the interaction between a pharmacological agent and its target tissue
- Study of the mechanism, intensity, peak and duration of a drug’s physiological actions
What changes in the old persons body affecting drug use?
- Changes in drug receptor sensitivity and receptor population
▫ affects sensitivity to pharmacological agents
▫ increased adverse effects - Homeostasis changes
▫ decreased capacity to respond to physiological challenges (e.g. orthostatic hypotension)
In what ways can meds be implicated in problems with the elderly?
- Medications and Falls
- Medications and Anti-cholinergic burden • Medications and Constipation
- Medications and Delirium
- Medications and Frailty
How do you go about categorising causes of falls?
What drug classes may increase falls?
• Syncopal
▫ Cardiac arrhythmia, neurological, orthostatic
hypotension
• Non- syncopal
▫ Environmental challenges
▫ Vision/Hearing Loss
▫ Delirium
• Iatrogenic falls risk increased by: – Sedatives – Antihypertensive medications – Drugs that prolong QT interval – Drugs that cause delirium – Drugs that reduce vision – Postural hypotension – Drugs causing Hypoglycaemia
What is an anticholinergic agent? How does it work? Categories?
- Blocks action of Acetylcholine at synapses in CNS + PNS
- Inhibits parasympathetic nerve impulses
• Divided into 3 categories:
▫ Antimuscarinic agents
▫ Ganglionic blockers
▫ Neuromuscular blockers
Anticholinergic effects?
- Dry mouth, constipation and urinary retention
- Linked to poor cognition and physical decline
- Associated with falls, and increased mortality and cardiovascular events.
Common meds that have anticholinergic effects?
- Antidepressants ( TCA)
- Antipsychotics
- Urinary antispasmodics
- Sedative medication
- Antihistamines
- H2 receptor antagonists
- Spasticity
- Others
Medications that cause constipation?
- Antacids
- Antimuscarinics
- Antidepressants
- Anti-epileptic medications
- Antipsychotics
- Calcium supplements
- Diuretics
- Iron supplements
- Opioids
Medications and delirium?
• Drugs are a common risk factor for delirium.
• Medications can account for 12–39% of delirium
cases.
• The most common medications to cause delirium are:
▫ Opiates
▫ Benzodiazipine medications
▫ Anti-cholinergic medications
Medications and frailty?
- Highest risk of medication side effects due to reduced physiological reserve
- Unlikely to derive any of the intended long term benefits
• Need to review treatment targets:
▫ BP–avoidBP<150/90if over 80
▫ Blood sugar control – avoid lowering HbA1c < 65 (T2DM)
▫ Avoid the use of combination blood thinners
▫ HR control – reduce/stop rate limiting medications if pulse < 60
How common are ADRs?
• ADRs are implicated in 6.5% of hospital
admissions
- Falls
- Bleeding
• ADRs are the 4th leading cause of death—ahead of pulmonary disease, diabetes, pneumonia, RTAs etc.
- NSAID – short course with PPI
- Diuretics – confirm indication
- Warfarin/DOACs – think about risk and benefit, in particular life expectancy
- Antibiotics – policy differs for older/frail patients!
Reasons for non-adherence?
- Affects up to 50% pts with chronic conditions
- Why is the patient non-adherent?
Unintentional:
- Cognitive impairment
- Sensory impairment
- Supervision/ administration
- Formulation/ swallowing
Intentional:
- Understanding/beliefs
- Self neglect
▫ What is keeping patients from using their meds?
▫ Set up reminders, organizational systems. …
▫ Identify cost-cutting strategies. …
▫ Address mental barriers and stigma. …
▫ Direct symptom, side effect management.
What resources can you uses for medications reconciliation?
• Solutions to these challenges :
▫ Beer’s Criteria
▫ STOPP/START
ID and reduction of inappropriate medication use, potential drug-drug interactions.
Medication class: ALPHA-ADRENERGIC ANTAGONISTS Example? Mechanism / Desired effect? Side effect / Adverse symptoms?
eg doxazosin
Has a direct effect on smooth muscles and also a level of spinal cord ganglia and nerve terminals
Can caused reduced bladder outlet resistance
Medication class: ALPHA-ADRENERGIC AGONISTS Example? Mechanism / Desired effect? Side effect / Adverse symptoms?
eg clonidine, methyldopa
Mimic action of norepinephrine at receptors
May contract bladder sphincter and cause retention
Medication class: ANTIPSYCHOTICS Example? Mechanism / Desired effect? Side effect / Adverse symptoms?
eg dopamine antagonists like haloperidol or serotonin receptors.
Gives alpha-adrenergic blockage, dopamine blockage, cholinergic action on the bladder.
Can lead to complex drug interactions.
Medication class: ANTIDEPRESSANTS Example? Mechanism / Desired effect? Side effect / Adverse symptoms?
Hard to generalise action; inhibitors of norepinephrine and or serotonin, some are antagonists at adrenergic, cholinergic or histaminergic receptors
Can lead to urinary retention / overflow incontinence.
Medication class:
DIURETICS
Mechanism / Desired effect?
Side effect / Adverse symptoms?
Formation of urine
Frequency, urgency, overwhelming bladder capacity.
Medication class: CCBs Example? Mechanism / Desired effect? Side effect / Adverse symptoms?
Decrease smooth muscle contractility in the bladder
Urinary retention / overflow
Medication class: SEDAtIVE/ HYPNOTICS Example? Mechanism / Desired effect? Side effect / Adverse symptoms?
Sedation, and relaxation of striated muscle (urethra).
Immobility / functional incontinence.
Weak flow / retention / overflow.
Medication class: MUSCLE RELAXANTS /SEDATIVE Example? Mechanism / Desired effect? Side effect / Adverse symptoms?
eg diazepam, chlordiazepoxide
Cause sedation or drowsiness; relax the urethra.
Frequency, stress incontinence, sedation.
Medication class:
ACEi, ARBs
Mechanism / Desired effect?
Side effect / Adverse symptoms?
Decrease both detrusor overactivity and urethral sphincter tone.
Reduced urge incontinence and increased stress incontinence.
Medication class: ANTIHISTAMINE Example? Mechanism / Desired effect? Side effect / Adverse symptoms?
eg chlorpheniramine
Relaxation of the bladder
Can lead to urinary retention.
