Introduction to Geriatrics / Aging

Damage to cells, tissues, and organs

- Decrease in number of myocytes
- Hypertrophy of remaining myocytes
- Stiffening of atrial and ventricular walls + aorta
- Dilation and calcification of valves
- Reduction in pacemaker cells in SA node

Diastolic dysfunction due to elevated LV end-diastolic pressure

Catecholamines

Leads to isolated systolic hypertension

- Decrease in brain mass
- Decrease in cerebral autoregulation
- Decrease in cerebral blood flow

- Dopaminergic
- Serotonergic
- Muscarinic

Increased BBB permeability = Increased risk of CNS AEs from drugs

Crystalized Abilities
- Increase over lifetime and remain intact through aging

Fluid abilities
- Peak in mid-twenties, decline slowly through sixties, then rapidly after

- Efficiency declines
- Increased time spent in Stages I and II of sleep
- Less in Stages III and IV
- Increased nighttime awakenings
- Often complain that sleep is non-restorative

TRUE

Decline

- Increase in residual lung volume and dead space
- Collapse of small airways
- Reduced arterial oxygen tension

Decrease

- Impaired tubular reabsorption of sodium
- Loss of concentrating ability of medullary tissue

FALSE -- Does not

FALSE -- Not a normal part of aging. Seek medical attention

- Epi
- NE
- Atrial natriuretic peptide
- Insulin
- PTH

*Increased body fat*

- Estradiol
- Testosterone/DHEA
- Growth hormone
- Calcitonin
- Renin
- Aldosterone
- EPO

*Reduction in muscle mass + Fluid/electrolyte imbalance*

TRUE

Pathology

- Decrease muscle mass = Increase fat
- Bone loss

Posture and gait changes

- Thinning of skin
- Loss of elasticity

- Wrinkling
- Telangiectasias
- Leathery texture
- Actinic keratoses

- Decreased
- Increased

FALSE -- Not normal, often encountered

- Decreased erythropoietin production
- Decreased testosterone
- Decreased B12 levels
- Inflammation

- Thymic involution = Reduction in active thymus tissue
- Loss of T-cell and B-cell diversity
- Decreased IL-2 production = Less B-cell proliferation
- Decreased response to vaccination

Elderly patients may not show typical signs of infection

- Presbyopia (loss of near vision)
- Sluggish accommodation to light
- Decrease in color distinction between blues and greens
- Cataracts after age 70

- Drier cerumen (ear wax) easily impacts
- Presbycusis (loss of high frequency hearing)
- Hearing difficulty

Muscle mass is reduced and body fat increases leading to PK changes such as:
- Decreased VD for water-soluble drugs
- Increased VD for fat-soluble drugs

Oral passive absorption often delayed
- Longer time to peak effect
- Lower peak concentration

May be lower due to decreased blood flow

Decreases Vd for hydrophilic drugs = Increases peak concentrations
- Ethanol
- Lithium
- AMGs

*LD of hydrophilic drugs should be reduced*

- Increase Vd for lipophilic drugs = Increases half life and time to steady state
- LD may need to be larger
- Maintenance doses may need to be lower or longer intervals in between
- Amiodarone
- Verapamil
- Benzos
- Antipsychotics

Decreases Vd of drugs that bind to muscle
- Digoxin

Higher rate of toxicity from increased unbound drug
- Phenytoin
- Warfarin

Increased binding of verapamil and propranolol

Digoxin

Often reduced leading to:
- Increased oral bioavailability
- At the BBB can lead to increased CNS concentrations of certain medications (verapamil)

Decreases in hepatic blood flow affect clearance of high-extraction drugs
- Reduction of first pass metabolism and prodrug activation
- Examples: amitriptyline, imipramine, lidocaine, morphine, propranolol, verapamil

Decline in GFR leads to increased levels of renally-cleared drugs

Reduced creatinine production with reduced muscle mass

FALSE -- Overestimates

Decreased response to beta blockers

Increased risk of EPS

Declines in cognitive function

Weakness, confusion, syncope abdominal pain, SOB, diaphoresis

- Incontinence, stomach pain, and confusion
- NO dysuria, frequency or urgency

- Malaise, anorexia, confusion
- Decompensation of pre-existing condition

- Preoccupation with somatic and cognitive symptoms: Constipation and urinary frequency
- Subsyndromal depression more common than major depressive disorder