Lecture 23: Drug Therapy in Geriatrics Flashcards
Why is geriatrics a unique specialty?
changes associated with primary aging
secondary aging
multimorbidity
geriatric syndromes
multiple medications
setting of care
policy decisions
psychosocial issues
ethics (and advocacy)
What is the definition of life span?
greatest age reached by any member of a species
What is the definition of life expectancy?
greatest age reached by members of a population
What are the age categories within older adults?
young-old (65-74)
middle-old (75-84)
old-old (85+)
What is a centenarian?
someone who has lived to be 100 years
What is a super centenarian?
someone who has lived to be 110 years
What is a semi-supercentenarian?
someone aged 105-109 years
What are the heath care considerations for geriatrics?
chronic conditions
76% of seniors have at least 1 chronic condition
What is multimorbidity?
associated with age
linear associated with number of medications
What is frailty?
a state of increased vulnerability from age-associated decline in reserve and function resulting in reduced ability to cope with everyday or acute stressors
no universally agreed upon definition
What is the pathophysiology of frailty?
a gradual decrease in physiological reserve occurs with aging
in frailty, this decrease is accelerated and homeostatic mechanisms start to fail
What is the definition of geriatric syndrome?
a multifactorial condition that involves the interaction between identifiable situation-specific stressors and underlying age-related risk factors, resulting in damage across multiple organ systems
What are key features of geriatric syndrome?
clinical and multifactorial conditions in older persons
associated with poor heath outcomes
do not fit into disease categories (comorbidities)
require a multidimensional treatment approach
What are the risks of geriatric syndromes?
clinical conditions that do not fit a disease category
multi-factorial, multi-system
What are potentially inappropriate medications?
also identified as “PIM”
a medication or medication class where harm outweighs the benefit, and there are safer alternatives available
the Beers Criteria are explicit
the Beers Criteria are used by CIHI to identify PIM
What is the goal of medication safety?
reduce severe, avoidable medication-related harm by 50% over 5 years
What are the priority actions of medication safety?
high risk situations; includes children, older adults
polypharmacy
transitions in care
Who is at risk for adverse drug reactions?
people with multiple chronic conditions
women
people over the age of 65
What is the definition of polypharmacy?
literal definition: 2 or more medications
most commonly accepted definition in practice: 5 or more medications (Rx or OTC)
the use of 2 or more drugs without indications or for the same purpose
the use of a drug to treat the adverse reactions of another drug
the use of 2 or more drugs from the same class to treat different indications
clinically meaningful: when a medication is not needed
What are prescribing cascades?
use of one drug to treat the adverse effects of another
What are potential prescribing omissions (PPO)?
undertreatment
not prescribing medications to patients who would benefit
often seen in patients with polypharmacy
What are examples of potential prescribing omissions?
statins for lipid management
anticoagulation for AF
LMWH for venous thromboprophylaxis
osteoporosis treatment
recent studies of hospitalized patients show 83% admitted had a PPO per START criteria
What are different forms of aging?
chronological aging
physiologic aging
social age
legal age
functional age
What is aging?
is NOT synonymous with disease
changes are experienced by all human beings
some changes may be due to lifestyle choices, social determinants of health, exposure to particular chemicals, etc.
What is physiological aging?
each organ system has changes associated with aging, which often start in the 5th decade
implications of these changes include:
reduced tissue/organ function
functional decline
increased susceptibility to disease
change in behavior
differences in PK and PD
What are physiological changes associated with aging?
body composition: increased fat
CV: decreased cardiac output, decreased beta sensitivity
Renal: decreased GFR, decreased nephrons
GI: decreased H+, increased gastric emptying time
Hepatic: decreased size, decreased blood flow
Nervous: decreased blood flow to CNS
Pulmonary: decreased cilia
Endocrine: decreased hormonal secretions
What are the effects on body composition that occur when aging?
loss of muscle mass: start ~age 40, accelerates in 6th decade (i.e. 50’s), by age 90, a person has half their muscle mass, some changes may be due to inactivity vs. physiologic aging
function and quality of muscle changes, along with neural stimulation, which slows
fat mass increases
What are the physiological changes to absorption in the GI tract?
increased gastric pH
decreased gastric acid secretion
decreased GI blood flow
decreased gastric surface area
decreased GI motility
What are the PK implications of the physiological changes to absorption in the GI tract?
potential for delay in absorption
minimal impact on extent of absorption of passively absorbed drugs
active transport (e.g. B12, iron, calcium) may be reduced
What are the physiological changes to absorption in the IM, topical?
decreased blood flow
decreased skin hydration
What are the PK implications of the physiological changes to absorption in the IM, topical?
slower, erratic, or lower absorption (e.g. antibiotics)
NB in immobile patients
higher absorption of topical steroids
NB if occlusive dressings
What is absorption of drugs in older adults?
most drugs are well absorbed in older adults
rate of absorption may be delayed in some patients
this is relevant for some treatments, e.g. immediate release levodopa, analgesia
drug absorption can also be affected by other conditions or medications
What is distribution of drugs in older adults?
distribution can be altered by aging or other disease states
lipid soluble drugs show an increase in Vd
protein changes with aging are insignificant and rarely have an impact on drug therapy
protein changes often occur with concurrent illness, not aging
What is metabolism of drugs in older adults?
drugs metabolized by Phase 2 are preferred in older adults
for medications oxidatively metabolized, reduce dose
multiple medications can have more dramatic drug interactions if impacting CYP P450
metabolism can be dramatically affected by illness, particularly acute illness
other factors affecting metabolism include chronic illness, genetics, diet, smoking, EtOH use
What is the elimination of drugs in older adults?
decreased renal elimination of drugs is the single most clinically significant change in PK due to aging
the majority of drug dosage adjustments in older adults are due to renal function
note: decreased muscle mass in frail older adults
CrCl is an estimate
What are changes to pharmacodynamics in older adults?
altered homeostatic balance manifested in a stress environment
change in homeostatic regulation
change in receptor responsiveness: change in receptor density, change in receptor affinity, post-receptor changes, change in negative feedback
implications: increased sensitivity to drugs
What are changes to the CNS in older adults?
higher cognitive function
mechanism: neuronal loss, receptor downregulation
examples: central anticholinergics, stimulants
What are changes to postural in older adults?
mechanism: fewer dopamine (D2) receptors in striatum
examples: antipsychotics, metaclopramide
What are changes to movement in older adults?
tardive dyskinesia
mechanism: impaired or decreased dopamine synthesizing neurons
examples: dopamine blockers, antipsychotics, anti-emetics (metoclopramide)
What are changes to blood pressure in older adults?
orthostasis
mechanism: blunting of beta response, receptor down-regulation, changes in vascular tree and autonomic nervous system
examples: BP meds, TCA, antipsychotics, diuretics
What are changes to CV in older adults?
arrhythmias
mechanism: cardiac hypersensitivity
examples: antiarrhythmic medication
What are changes to coagulation in older adults?
anticoagulation
mechanism: poor hepatic production of coagulation factors, dietary intake
examples: anticoagulants, thrombolytics
What are changes to visceral muscle in older adults?
mechanism: visual disturbances (pupillary autonomic responses)
bladder instability (detrusor contractions)
intestinal motility decreased
examples: anticholinergics
What are changes to temperature in older adults?
thermoregulation
mechanism: poor temperature regulating mechanisms
examples: meds affecting awareness, mobility, muscular activity, vasoconstrictor mechanisms; CNS meds
